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IIS 8.5 Server Security Technical Implementation Guide

Version 1 Release 82
2019-07-262018-01-26
U_MS_IIS_8-5_Server_STIG_V1R82_Manual-xccdf.xml
This Security Technical Implementation Guide is published as a tool to improve the security of Department of Defense (DoD) information systems. The requirements are derived from the National Institute of Standards and Technology (NIST) 800-53 and related documents. Comments or proposed revisions to this document should be sent via email to the following address: disa.stig_spt@mail.mil.

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  • Updated 14
  • Added 4
  • Removed 1

Vulnerabilities (48)

Added

V-76691

The IIS 8.5 web server log files must only be accessible by privileged users.

Finding ID
IISW-SV-000113
Rule ID
SV-91387r2_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000118-WSR-000068
CCI
CCI-000162
Target Key
(None)
Documentable
No
Discussion

A major tool in exploring the website use, attempted use, unusual conditions, and problems are the access and error logs. In the event of a security incident, these logs can provide the SA and the web manager with valuable information. To verify the integrity of the log files and protect the SA and the web manager from a conflict of interest related to the maintenance of these files, only the members of the Auditors group will be granted permissions to move, copy, and delete these files in the course of their duties related to the archiving of these files.

Fix Text

Remove Write permissions from any users other than auditors. Remove Read permissions from any users other than auditors, System Administrators, or Web Administrators. Remove greater than Read permissions from any users other than auditors and SYSTEM.

Check Content

Query the SA to determine who has update access to the web server log files. The role of auditor and the role of SA should be distinctly separate. An individual functioning as an auditor should not also serve as an SA due to a conflict of interest. Only management authorized individuals with a privileged ID or group ID associated with an auditor role will have access permission to log files that are greater than read on web servers he or she has been authorized to audit. Only management authorized individuals with a privileged ID or group ID associated with either an SA or web administrator role may have read authority to log files for the web servers he or she has been authorized to administer. No other individuals may access log files. If IDs associated with roles other than auditors, SAs, or web administrators have any access to log files, this is a finding. If an SA or web administrator has greater than read authority to the log files, this is a finding. This check does not apply to service IDs utilized by automated services necessary to process, manage, and store log files.

Added

V-76693

The log information from the IIS 8.5 web server must be protected from unauthorized modification.

Finding ID
IISW-SV-000114
Rule ID
SV-91389r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000119-WSR-000069
CCI
CCI-000163
Target Key
(None)
Documentable
No
Discussion

A major tool in exploring the website use, attempted use, unusual conditions, and problems are the access and error logs. In the event of a security incident, these logs can provide the SA and the web manager with valuable information. Failure to protect log files could enable an attacker to modify the log file data or falsify events to mask an attacker's activity.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Click the "Browse" button and navigate to the directory where the log files are stored. Right-click the log file name to review and click “Properties”. Click the "Security" tab. Set the log file permissions for the appropriate group(s). Click "OK". Select "Apply" in the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Click the "Browse" button and navigate to the directory where the log files are stored. Right-click the log file name to review and click “Properties”. Click the "Security" tab. Verify only authorized groups are listed, if others are listed, this is a finding. If any auditors, SA or web administrators have greater than read authority to log files, this is a finding. This check does not apply to service IDs utilized by automated services necessary to process, manage, and store log files.

Added

V-76723

The IIS 8.5 web server Session State cookie settings must be configured to regenerate expired session IDs.

Finding ID
IISW-SV-000133
Rule ID
SV-91419r2_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000220-WSR-000201
CCI
CCI-001185
Target Key
(None)
Documentable
No
Discussion

Captured sessions can be reused in "replay" attacks. This requirement limits the ability of adversaries from capturing and continuing to employ previously valid session IDs. Session IDs are tokens generated by web applications to uniquely identify an application user's session. Unique session IDs help to reduce predictability of said identifiers. When a user logs out, or when any other session termination event occurs, the web server must terminate the user session to minimize the potential for an attacker to hijack that particular user session. Cookies associate session information with client information for the duration of a user’s connection to a website. Using cookies is a more efficient way to track session state than any of the methods that do not use cookies because cookies do not require any redirection.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.web/sessionState". Set "cookieless" to "UseCookies". Set "regenerateExpiredSessionID" to "True". Click "Apply" under the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.web/sessionState". Verify "cookieless" is set to "UseCookies". Verify the "regenerateExpiredSessionID" is set to "True". If "cookieless" is not set to "UseCookies" and/or the "regenerateExpiredSessionID" is not set to "true", this is a finding.

Added

V-76763

The IIS 8.5 web server must install security-relevant software updates within the configured time period directed by an authoritative source (e.g., IAVM, CTOs, DTMs, and STIGs).

Finding ID
IISW-SV-000155
Rule ID
SV-91459r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000456-WSR-000187
CCI
CCI-002605
Target Key
(None)
Documentable
No
Discussion

Several vulnerabilities are associated with older versions of web server software. As hot fixes and patches are issued, these solutions are included in the next version of the server software. Maintaining the web server at a current version makes the efforts of a malicious user more difficult.

Fix Text

Install the current version of the web server software and maintain appropriate service packs and patches.

Check Content

Determine the most recent patch level of the IIS 8.5 software, as posted on the Microsoft website. Open the IIS 8.5 Manager. Click "Help", and select "About Internet Information Services". If the version is less than one version behind the most recent patch level, this is a finding.

Removed

V-95633

The IIS 8.5 MaxConnections setting must be configured to limit the number of allowed simultaneous session requests.

Finding ID
IISW-SV-000200
Rule ID
SV-104771r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000001-WSR-000001
CCI
CCI-000054
Target Key
(None)
Documentable
No
Discussion

Resource exhaustion can occur when an unlimited number of concurrent requests are allowed on a website, facilitating a Denial of Service attack. Mitigating this kind of attack will include limiting the number of concurrent HTTP/HTTPS requests per IP address and may include, where feasible, limiting parameter values associated with keepalive (i.e., a parameter used to limit the amount of time a connection may be inactive).

Fix Text

Access the IIS 8.5 IIS Manager. Click the IIS 8.5 server. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.applicationHost/sites". Expand "siteDefaults". Expand "limits". Set the "maxconnections" parameter to a value greater than zero.

Check Content

Access the IIS 8.5 IIS Manager. Click the IIS 8.5 server. Select "Configuration Editor" under the "Management" section. From the "Section:" drop-down list at the top of the configuration editor, locate "system.applicationHost/sites". Expand "siteDefaults". Expand "limits". Review the results and verify the value is greater than zero for the "maxconnections" parameter. If the maxconnections parameter is set to zero, this is a finding.

An IIS 8.5 web server behind a load balancer or proxy server, must produce log records containing the source client IP and destination information.

Finding ID
IISW-SV-000109
Rule ID
SV-91381r2_rule91381r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000098-WSR-000060
CCI
CCI-000133
Target Key
(None)
Documentable
No
Discussion

Web server logging capability is critical for accurate forensic analysis. Without sufficient and accurate information, a correct replay of the events cannot be determined. Ascertaining the correct source, e.g. source IP, of the events is important during forensic analysis. Correctly determining the source of events will add information to the overall reconstruction of the logable event. By determining the source of the event correctly, analysis of the enterprise can be undertaken to determine if events tied to the source occurred in other areas within the enterprise. A web server behind a load balancer or proxy server, when not configured correctly, will record the load balancer or proxy server as the source of every logable event. When looking at the information forensically, this information is not helpful in the investigation of events. The web server must record with each event the client source of the event.

Fix Text

Access the proxy server through which inbound web traffic is passed and configure settings to pass web traffic to the IIS 8.5 web server transparently.

Check Content

Interview the System Administrator to review the configuration of the IIS 8.5 architecture and determine if inbound web traffic is passed through a proxy. If the IIS 8.5 web server is receiving inbound web traffic through a proxy, the audit logs must be reviewed to determine if correct source information is being passed through by the proxy server. Follow this procedure for web server and each website: Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Click on "View log files" under the "Actions" pane. When the log file is displayed, review source IP information in log entries and verify the entries do not reflect the IP address of the proxy server. If the website is not behind a load balancer or proxy server, this is Not Applicable. If the log entries in the log file(s) reflect the IP address of the proxy server as the source, this is a finding. If provisions have been made to log the client IP via another field (i.e., utilizing X-Forwarded-For), this is not a finding.

The IIS 8.5 web server must produce log records that contain sufficient information to establish the outcome (success or failure) of IIS 8.5 web server events.

Finding ID
IISW-SV-000110
Rule ID
SV-91383r3_rule91383r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000099-WSR-000061
CCI
CCI-000134
Target Key
(None)
Documentable
No
Discussion

Web server logging capability is critical for accurate forensic analysis. Without sufficient and accurate information, a correct replay of the events cannot be determined. Ascertaining the success or failure of an event is important during forensic analysis. Correctly determining the outcome will add information to the overall reconstruction of the logable event. By determining the success or failure of the event correctly, analysis of the enterprise can be undertaken to determine if events tied to the event occurred in other areas within the enterprise. Without sufficient information establishing the success or failure of the logged event, investigation into the cause of event is severely hindered. The success or failure also provides a means to measure the impact of an event and help authorized personnel to determine the appropriate response. Log record content that may be necessary to satisfy the requirement of this control includes, but is not limited to, time stamps, source and destination IP addresses, user/process identifiers, event descriptions, application-specific events, success/fail indications, file names involved, access control, or flow control rules invoked.

Fix Text

Access the IIS 8.5 web server IIS Manager. Click the IIS 8.5 web server name. Under "IIS", double-click the "Logging" icon. Verify the "Format:" under "Log File" is configured to "W3C". Select the "Fields" button. Under "Custom Fields", click the "Add Field..." button. For each field being added, give a name unique to what the field is capturing. Click on the "Source Type" drop-down list and select "Request Header". Click on the "Source" drop-down list and select "Connection". Click OK to add. Click on the "Source Type" drop-down list and select "Request Header". Click on the "Source" drop-down list and select "Warning". Click OK to add. Click on the "Source Type" drop-down list and select "Server Variable". Click on the "Source" drop-down list and select "HTTP_CONNECTION". Click OK to add. Click "OK". Click "Apply" under the "Actions" pane.

Check Content

Access the IIS 8.5 web server IIS Manager. Click the IIS 8.5 web server name. Under "IIS", double-click the "Logging" icon. Verify the "Format:" under "Log File" is configured to "W3C". Select the "Fields" button. Under "Custom Fields", verify the following fields have been configured: Request Header >> Connection Request Header >> Warning Server Variable >> HTTP_CONNECTION If any of the above fields are not selected, this is a finding.

The IIS 8.5 web server must produce log records containing sufficient information to establish the identity of any user/subject or process associated with an event.

Finding ID
IISW-SV-000111
Rule ID
SV-91385r3_rule91385r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000100-WSR-000064
CCI
CCI-001487
Target Key
(None)
Documentable
No
Discussion

Web server logging capability is critical for accurate forensic analysis. Without sufficient and accurate information, a correct replay of the events cannot be determined. Determining user accounts, processes running on behalf of the user, and running process identifiers also enable a better understanding of the overall event. User tool identification is also helpful to determine if events are related to overall user access or specific client tools. Log record content that may be necessary to satisfy the requirement of this control includes: time stamps, source and destination addresses, user/process identifiers, event descriptions, success/fail indications, file names involved, and access control or flow control rules invoked.

Fix Text

Access the IIS 8.5 web server IIS Manager. Click the IIS 8.5 web server name. Under "IIS", double-click the "Logging" icon. Verify the "Format:" under "Log File" is configured to "W3C". Select the "Fields" button. Under "Standard Fields", select "User Agent", "User Name" and "Referrer". Under "Custom Fields", select the following fields: Click on the "Source Type" drop-down list and select "Request Header". Click on the "Source" drop-down list and select "User-Agent". Click OK to add. Click on the "Source Type" drop-down list and select "Request Header". Click on the "Source" drop-down list and select "Authorization". Click OK to add. Click on the "Source Type" drop-down list and select "Request Header". Click on the "Source" drop-down list and select "Content-Type". Click OK to add. Click on the "Source Type" drop-down list and select "Server Variable". Click on the "Source" drop-down list and select "HTTP_USER_AGENT". Click OK to add. Click "OK". Click "Apply" under the "Actions" pane.

Check Content

Note: If SSL is installed on load balancer through which traffic is routed to the IIS 8.5 server, and the IIS 8.5 server ONLY receives traffic from the load balancer, the SSL requirement must be met on the load balancer. Access the IIS 8.5 web server IIS Manager. Click the IIS 8.5 web server name. Under "IIS", double-click the "Logging" icon. Verify the "Format:" under "Log File" is configured to "W3C". Select the "Fields" button. Under "Standard Fields", verify "User Agent", "User Name" and "Referrer" are selected. Under "Custom Fields", verify the following field have been configured: Server Variable >> HTTP_USER_AGENT Request Header >> User-Agent Request Header >> Authorization Response Header >> Content-Type If any of the above fields are not selected, this is a finding.

The log information from the IIS 8.5 web server must be protected from unauthorized modification or deletion.

Finding ID
IISW-SV-000115
Rule ID
SV-91391r4_rule91391r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000120-WSR-000070
CCI
CCI-000164
Target Key
(None)
Documentable
No
Discussion

A major tool in exploring the website use, attempted use, unusual conditions, and problems are the access and error logs. In the event of a security incident, these logs can provide the SA and the web manager with valuable information. Failure to protect log files could enable an attacker to modify the log file data or falsify events to mask an attacker's activity.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Click the "Browse" button and navigate to the directory where the log files are stored. Right-click the log file name to review and click “Properties”. Click the "Security" tab. Set the log file permissions for the appropriate group(s). Click "OK". Select "Apply" in the "Actions" pane.

Check Content

This check does not apply to service account IDs utilized by automated services necessary to process, manage, and store log files. Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Click the "Browse" button and navigate to the directory where the log files are stored. Right-click the log file name to review. Clickand click Properties”.. Click the "Security" tab. Verify logonly fileauthorized accessgroups isare restrictedlisted, asif follows.others Otherwiseare listed, this is a finding. EventlogNote: -The Fulllog Controlfile SYSTEMshould -be Fullrestricted Controlas follows: Administrators, -SYSTEM, FullTrustedInstaller, ControlAuditors Webgroup: Managers - ReadFull

The log data and records from the IIS 8.5 web server must be backed up onto a different system or media.

Finding ID
IISW-SV-000116
Rule ID
SV-91393r2_rule91393r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000125-WSR-000071
CCI
CCI-001348
Target Key
(None)
Documentable
No
Discussion

Protection of log data includes assuring log data is not accidentally lost or deleted. Backing up log records to an unrelated system or onto separate media than the system the web server is actually running on helps to assure that, in the event of a catastrophic system failure, the log records will be retained.

Fix Text

Configure system backups to include the directory paths of all IIS 8.5 web server and website log files.

Check Content

The IIS 8.5 web server and website log files should be backed up by the system backup. To determine if log files are backed up by the system backup, determine the location of the web server log files and each website's log files. Open the IIS 8.5 Manager. Click the IIS 8.5 server name. Click the "Logging" icon. Under "Log File" >> "Directory" obtain the path of the log file. Once all locations are known, consult with the System Administrator to review the server's backup procedure and policy. Verify the paths of all log files are part of the system backup. Verify log files are backed up to an unrelated system or onto separate media than the system the web server is running on. If the paths of all log files are not part of the system backup and/or not backed up to a separate media, this is a finding.

The IIS 8.5 web server must perform RFC 5280-compliant certification path validation.

Finding ID
IISW-SV-000129
Rule ID
SV-91411r3_rule91411r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000175-WSR-000095
CCI
CCI-000185
Target Key
(None)
Documentable
No
Discussion

This check verifies the server certificate is actually a DoD-issued certificate used by the organization being reviewed. This is used to verify the authenticity of the website to the user. If the certificate is not issued by the DoD or if the certificate has expired, then there is no assurance the use of the certificate is valid. The entire purpose of using a certificate is, therefore, compromised.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Server Certificate" icon. Import a valid DoD certificate and remove any non-DoD certificates.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Server Certificate" icon. Double-click each certificate and verify the certificate path is to a DoD root CA. If the “Issued By” field of the PKI certificate being used by the IIS 8.5 server/site does not indicate the issuing Certificate Authority (CA) is part of the DoD PKI or an approved ECA, this is a finding.

The IIS 8.5 web server must use cookies to track session state.

Finding ID
IISW-SV-000134
Rule ID
SV-91421r4_rule91421r2_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000223-WSR-000011
CCI
CCI-001664
Target Key
(None)
Documentable
No
Discussion

Cookies are used to exchange data between the web server and the client. Cookies, such as a session cookie, may contain session information and user credentials used to maintain a persistent connection between the user and the hosted application since HTTP/HTTPS is a stateless protocol. Cookies associate session information with client information for the duration of a user’s connection to a website. Using cookies is a more efficient way to track session state than any of the methods that do not use cookies because cookies do not require any redirection.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "ASP.Net", double-click on the "Session State" icon. Under "Cookie Settings", select "Use Cookies” from the "Mode" drop-down list. Select the "Regenerate expired session ID" check box. Click "Apply" in the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "ASP.Net", double-click on the "Session State" icon. Under "Cookie Settings", verify the "Mode" has "Use Cookies" selected from the drop-down list. Verify the "Regenerate expired session ID" check box is selected. If the "Cookie Settings" "Mode" is not set to "Use Cookies", thisand isthe a"Regenerate finding.expired Note:session IfID" IIScheck 8.5box server/site is used only for system-to-system maintenance, does not allow users to connect to interfaceselected, and is restricted to specific system IPs, this is Nota Applicablefinding.

The IIS 8.5 web server must limit the amount of time a cookie persists.

Finding ID
IISW-SV-000135
Rule ID
SV-91423r3_rule91423r2_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000223-WSR-000145
CCI
CCI-001664
Target Key
(None)
Documentable
No
Discussion

ASP.NET provides a session state, which is available as the HttpSessionState class, as a method of storing session-specific information that is visible only within the session. ASP.NET session state identifies requests from the same browser during a limited time window as a session, and provides the ability to persist variable values for the duration of that session. Cookies associate session information with client information for the duration of a user’s connection to a website. Using cookies is a more efficient way to track session state than any of the methods that do not use cookies because cookies do not require any redirection.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under the "ASP.NET" section, select "Session State". Under "Cookie Settings", select the "Use Cookies" mode from the "Mode:" drop-down list. Under “Time-out (in minutes), enter a value of “20 or less”.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under the "ASP.NET" section, select "Session State". Under "Cookie Settings", verify the "Use Cookies" mode is selected from the "Mode:" drop-down list. Under Time-out (in minutes), verify “20 minutes or less” is selected. If the "Use Cookies” mode is selected and Time-out (in minutes) is configured for “20 minutes or less”, this is not a finding. Note: If IIS 8.5 server/site is used only for system-to-system maintenance, does not allow users to connect to interface, and is restricted to specific system IPs, this is Not Applicable.

The production IIS 8.5 web server must utilize SHA2 encryption for the Machine Key.

Finding ID
IISW-SV-000137
Rule ID
SV-91427r2_rule91427r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000231-WSR-000144
CCI
CCI-001199
Target Key
(None)
Documentable
No
Discussion

The Machine Key element of the ASP.NET web.config specifies the algorithm and keys that ASP.NET will use for encryption. The Machine Key feature can be managed to specify hashing and encryption settings for application services such as view state, forms authentication, membership and roles, and anonymous identification. Ensuring a strong encryption method can mitigate the risk of data tampering in crucial functional areas such as forms authentication cookies, or view state.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Machine Key" icon in the web server Home Pane. Set the Validation method to "HMACSHA256" or stronger. Set the Encryption method to "Auto". Click "Apply" in the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Machine Key" icon in the website Home Pane. Verify "HMACSHA256" or stronger encryption is selected for the Validation method and "Auto" is selected for the Encryption method. If "HMACSHA256" or stronger encryption is not selected for the Validation method and/or "Auto" is not selected for the Encryption method, this is a finding.

The IIS 8.5 web server Indexing must only index web content.

Finding ID
IISW-SV-000139
Rule ID
SV-91431r2_rule91431r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000266-WSR-000142
CCI
CCI-001312
Target Key
(None)
Documentable
No
Discussion

The indexing service can be used to facilitate a search function for websites. Enabling indexing may facilitate a directory traversal exploit and reveal unwanted information to a malicious user. Indexing must be limited to web document directories only.

Fix Text

Run MMC. Add the Indexing Service snap-in. Edit the indexed directories to only include web document directories.

Check Content

Access the IIS 8.5 Web Server. Access an administrator command prompt and type "regedit <enter>" to access the server's registry. Navigate to HKEY_LOCAL_MACHINEKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ContentIndex\Catalogs\. If this key exists, then indexing is enabled.; Ifif the key does not exist, then this check is Not Applicable. Review the CatalogCatalogs keys to determine if directories other than web document directories are being indexed. If so, this is a finding.

Warning and error messages displayed to clients must be modified to minimize the identity of the IIS 8.5 web server, patches, loaded modules, and directory paths.

Finding ID
IISW-SV-000140
Rule ID
SV-91433r2_rule91433r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000266-WSR-000159
CCI
CCI-001312
Target Key
(None)
Documentable
No
Discussion

HTTP error pages contain information that could enable an attacker to gain access to an information system. Failure to prevent the sending of HTTP error pages with full information to remote requesters exposes internal configuration information to potential attackers.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Error Pages" icon. Click oneach any error message and click "Edit Feature Setting" from the "Actions" Pane. ThisSet willeach apply to all error messages.message Set Feature Setting to “Detailed errors for local requests and custom error pages for remote requests”.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Error Pages" icon. Click oneach any error message and click "Edit Feature Setting" from the "Actions" Pane. ThisIf willany apply to all error messages.message If the feature setting is not set to “Detailed errors for local requests and custom error pages for remote requests”, this is a finding.

The IIS 8.5 web server must restrict inbound connections from nonsecure zones.

Finding ID
IISW-SV-000142
Rule ID
SV-91437r2_rule91437r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000315-WSR-000004
CCI
CCI-002314
Target Key
(None)
Documentable
No
Discussion

Remote access to the web server is any access that communicates through an external, non-organization-controlled network. Remote access can be used to access hosted applications or to perform management functions. A web server can be accessed remotely and must be capable of restricting access from what the DoD defines as nonsecure zones. Nonsecure zones are defined as any IP, subnet, or region that is defined as a threat to the organization. The nonsecure zones must be defined for public web servers logically located in a DMZ, as well as private web servers with perimeter protection devices. By restricting access from nonsecure zones, through internal web server access list, the web server can stop or slow denial of service (DoS) attacks on the web server.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "Management", double-click "Management Service". Stop the Web Management Service under the "Actions" pane. Configure only known, secure IP ranges are configured as "Allow". Select "Apply" in "Actions" pane. Restart the Web Management Service under the "Actions" pane.

Check Content

Note: ThisThe requirement applies to the Web Management Service.Tools Ifmust thebe Webinstalled Managementin Serviceorder isto notvalidate installed, this is Not Applicablerequirement. Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "Management", double-click "Management Service". If "Enable remote connections" is not selected, this is Not Applicable. If "Enable remote connections" is selected, review the entries under "IP Address Restrictions". Verify only known, secure IP ranges are configured as "Allow". If "IP Address Restrictions" are not configured or IP ranges configured to be "Allow" are not restrictive enough to prevent connections from nonsecure zones, this is a finding.

An IIS 8.5 web server must maintain the confidentiality of controlled information during transmission through the use of an approved TLS version.

Finding ID
IISW-SV-000153
Rule ID
SV-91455r2_rule91455r1_rule
Severity
Cat I
CCE
(None)
Group Title
SRG-APP-000439-WSR-000156
CCI
CCI-002418
Target Key
(None)
Documentable
No
Discussion

Transport Layer Security (TLS) encryption is a required security setting for a private web server. Encryption of private information is essential to ensuring data confidentiality. If private information is not encrypted, it can be intercepted and easily read by an unauthorized party. A private web server must use a FIPS 140-2-approved TLS version, and all non-FIPS-approved SSL versions must be disabled. FIPS 140-2-approved TLS versions include TLS V1.1 or greater. NIST SP 800-52 specifies the preferred configurations for government systems.

Fix Text

Access the IIS 8.5 Web Server. Access an administrator command prompt and type "regedit <enter>" to access the server's registry. Navigate to the following registry paths and configure the "DisabledByDefault" REG_DWORD with the appropriate values: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server With a REG_DWORD value of "0" for "DisabledByDefault" HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server With a REG_DWORD value of "1" for "DisabledByDefault" With a REG_DWORD value of "0" for "Enabled"

Check Content

Access the IIS 8.5 Web Server. Access an administrator command prompt and type "regedit <enter>" to access the server's registry. Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.2\Server Verify a REG_DWORD value of "0" for "DisabledByDefault" Navigate to: HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 2.0\Server HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\SSL 3.0\Server Verify a REG_DWORD value of "1" for "DisabledByDefault" Verify a REG_DWORD value of "0" for "Enabled" If any of the respective registry paths doare not existexistent or are configured with the wrong value, this is a finding.

The IIS 8.5 web server must have a global authorization rule configured to restrict access.

Finding ID
IISW-SV-000159
Rule ID
SV-91467r2_rule91467r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000516-WSR-000174
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

Authorization rules can be configured at the server, website, folder (including Virtual Directories), or file level. It is recommended that URL Authorization be configured to only grant access to the necessary security principals. Configuring a global Authorization rule that restricts access ensures inheritance of the settings down through the hierarchy of web directories. This will ensure access to current and future content is only granted to the appropriate principals, mitigating risk of unauthorized access.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the ".NET Authorization Rules" icon under the "ASP.NET" section. Remove all users other than Administrator”. .

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the ".NET Authorization Rules" icon under the "ASP.NET" section. If any user other than Administrator is listed, this is a finding.

The IIS 8.5 web server remote authors or content providers must only use secure encrypted logons and connections to upload web server content.

Finding ID
IISW-SV-000100
Rule ID
SV-91375r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000015-WSR-000014
CCI
CCI-001453
Target Key
(None)
Documentable
No
Discussion

Logging onto a web server remotely using an unencrypted protocol or service when performing updates and maintenance is a major risk. Data, such as user account, is transmitted in plaintext and can easily be compromised. When performing remote administrative tasks, a protocol or service that encrypts the communication channel must be used. An alternative to remote administration of the web server is to perform web server administration locally at the console. Local administration at the console implies physical access to the server.

Fix Text

Ensure the web server administration is only performed over a secure path.

Check Content

If web administration is performed at the console, this check is NA. If web administration is performed remotely the following checks will apply: If administration of the server is performed remotely, it will only be performed securely by system administrators. If website administration or web application administration has been delegated, those users will be documented and approved by the ISSO. Remote administration must be in compliance with any requirements contained within the Windows Server STIGs, and any applicable Network STIGs. Remote administration of any kind will be restricted to documented and authorized personnel. All users performing remote administration must be authenticated. All remote sessions will be encrypted and they will utilize FIPS 140-2-approved protocols. FIPS 140-2-approved TLS versions include TLS V1.1 or greater. Review with site management how remote administration, if applicable, is configured on the website. If remote management meets the criteria listed above, this is not a finding. If remote management is utilized and does not meet the criteria listed above, this is a finding.

The enhanced logging for the IIS 8.5 web server must be enabled and capture all user and web server events.

Finding ID
IISW-SV-000102
Rule ID
SV-91377r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000092-WSR-000055
CCI
CCI-001464
Target Key
(None)
Documentable
No
Discussion

Log files are a critical component to the successful management of an IS used within the DoD. By generating log files with useful information web administrators can leverage them in the event of a disaster, malicious attack, or other site specific needs. Ascertaining the correct order of the events that occurred is important during forensic analysis. Events that appear harmless by themselves might be flagged as a potential threat when properly viewed in sequence. By also establishing the event date and time, an event can be properly viewed with an enterprise tool to fully see a possible threat in its entirety. Without sufficient information establishing when the log event occurred, investigation into the cause of event is severely hindered. Log record content that may be necessary to satisfy the requirement of this control includes, but is not limited to, time stamps, source and destination IP addresses, user/process identifiers, event descriptions, application-specific events, success/fail indications, file names involved, access control, or flow control rules invoked. Satisfies: SRG-APP-000092-WSR-000055, SRG-APP-000093-WSR-000053, SRG-APP-000095-WSR-000056, SRG-APP-000096-WSR-000057, SRG-APP-000097-WSR-000058, SRG-APP-000097-WSR-000059

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Under Format select "W3C". Select the following fields: Date, Time, Client IP Address, User Name, Method, URI Query, Protocol Status, and Referrer. Under the "Actions" pane, click "Apply".

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Click the "Logging" icon. Under Format select "W3C". Click "Select Fields", verify at a minimum the following fields are checked: Date, Time, Client IP Address, User Name, Method, URI Query, Protocol Status, and Referrer. If not, this is a finding.

Both the log file and Event Tracing for Windows (ETW) for the IIS 8.5 web server must be enabled.

Finding ID
IISW-SV-000103
Rule ID
SV-91379r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000092-WSR-000055
CCI
CCI-001851
Target Key
(None)
Documentable
No
Discussion

Internet Information Services (IIS) on Windows Server 2012 provides basic logging capabilities. However, because IIS takes some time to flush logs to disk, administrators do not have access to logging information in real-time. In addition, text-based log files can be difficult and time-consuming to process. In IIS 8.5, the administrator has the option of sending logging information to Event Tracing for Windows (ETW). This option gives the administrator the ability to use standard query tools, or create custom tools, for viewing real-time logging information in ETW. This provides a significant advantage over parsing text-based log files that are not updated in real time. Satisfies: SRG-APP-000092-WSR-000055, SRG-APP-000108-WSR-000166, SRG-APP-000358-WSR-000063

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 server name. Click the "Logging" icon. Under Log Event Destination, select the "Both log file and ETW event" radio button. Under the "Actions" pane, click "Apply".

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 server name. Click the "Logging" icon. Under Log Event Destination, verify the "Both log file and ETW event" radio button is selected. If the "Both log file and ETW event" radio button is not selected, this is a finding.

The IIS 8.5 web server must not perform user management for hosted applications.

Finding ID
IISW-SV-000117
Rule ID
SV-91395r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000015
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

User management and authentication can be an essential part of any application hosted by the web server. Along with authenticating users, the user management function must perform several other tasks like password complexity, locking users after a configurable number of failed logons, and management of temporary and emergency accounts; and all of this must be done enterprise-wide. The web server contains a minimal user management function, but the web server user management function does not offer enterprise-wide user management, and user management is not the primary function of the web server. User management for the hosted applications should be done through a facility that is built for enterprise-wide user management, like LDAP and Active Directory.

Fix Text

Reconfigure any hosted applications on the IIS 8.5 web server to perform user management outside the IIS 8.5 web server. Document how the hosted application user management is accomplished.

Check Content

Interview the System Administrator about the role of the IIS 8.5 web server. If the IIS 8.5 web server is hosting an application, have the SA provide supporting documentation on how the application's user management is accomplished outside of the IIS 8.5 web server. If the IIS 8.5 web server is not hosting an application, this is Not Applicable. If the IIS web server is performing user management for hosted applications, this is a finding. If the IIS 8.5 web server is hosting an application and the SA cannot provide supporting documentation on how the application's user management is accomplished outside of the IIS 8.5 web server, this is a finding.

The IIS 8.5 web server must only contain functions necessary for operation.

Finding ID
IISW-SV-000118
Rule ID
SV-91397r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000075
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

A web server can provide many features, services, and processes. Some of these may be deemed unnecessary or too unsecure to run on a production DoD system. The web server must provide the capability to disable, uninstall, or deactivate functionality and services that are deemed to be non-essential to the web server mission or can adversely impact server performance.

Fix Text

Remove all unapproved programs and roles from the production IIS 8.5 web server.

Check Content

Click on “Start”. Open Control Panel. Click on “Programs”. Click on “Programs and Features”. Review the installed programs, if any programs are installed other than those required for the IIS 8.5 web services, this is a finding. Note: If additional software is needed supporting documentation must be signed by the ISSO.

The IIS 8.5 web server must not be both a website server and a proxy server.

Finding ID
IISW-SV-000119
Rule ID
SV-91399r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000076
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

A web server should be primarily a web server or a proxy server but not both, for the same reasons that other multi-use servers are not recommended. Scanning for web servers that will also proxy requests into an otherwise protected network is a very common attack making the attack anonymous.

Fix Text

Open the IIS 8.5 Manager. Under the "Connections" pane on the left side of the management console, select the IIS 8.5 web server. Under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature. From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...". In the "Application Request Routing" settings window, remove the check from the "Enable proxy" check box. Click "Apply" in the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Under the "Connections" pane on the left side of the management console, select the IIS 8.5 web server. If, under the IIS installed features, "Application Request Routing Cache" is not present, this is not a finding. If, under the IIS installed features, "Application Request Routing Cache" is present, double-click the icon to open the feature. From the right "Actions" pane, under "Proxy", select "Server Proxy Settings...". In the "Application Request Routing" settings window, verify whether "Enable proxy" is selected. If “Enable proxy" is selected under the "Application Request Routing" settings, this is a finding.

All IIS 8.5 web server sample code, example applications, and tutorials must be removed from a production IIS 8.5 server.

Finding ID
IISW-SV-000120
Rule ID
SV-91401r1_rule
Severity
Cat I
CCE
(None)
Group Title
SRG-APP-000141-WSR-000077
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

Web server documentation, sample code, example applications, and tutorials may be an exploitable threat to a web server. A production web server may only contain components that are operationally necessary (i.e., compiled code, scripts, web content, etc.). Delete all directories containing samples and any scripts used to execute the samples.

Fix Text

Remove any executable sample code, example applications, or tutorials which are not explicitly used by a production website.

Check Content

Navigate to the following folders: inetpub\ Program Files\Common Files\System\msadc Program Files (x86)\Common Files\System\msadc If the folder or sub-folders contain any executable sample code, example applications, or tutorials which are not explicitly used by a production website, this is a finding.

The accounts created by uninstalled features (i.e., tools, utilities, specific, etc.) must be deleted from the IIS 8.5 server.

Finding ID
IISW-SV-000121
Rule ID
SV-91403r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000078
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

When accounts used for web server features such as documentation, sample code, example applications, tutorials, utilities, and services are created even though the feature is not installed, they become an exploitable threat to a web server. These accounts become inactive, are not monitored through regular use, and passwords for the accounts are not created or updated. An attacker, through very little effort, can use these accounts to gain access to the web server and begin investigating ways to elevate the account privileges. The accounts used for web server features not installed must not be created and must be deleted when these features are uninstalled.

Fix Text

Access the IIS 8.5 web server. Access “Apps” menu. Under “Administrative Tools”, select “Computer Management”. In left pane, expand "Local Users and Groups" and click on "Users". Delete any local accounts which were created by features which have been uninstalled or are not used.

Check Content

Access the IIS 8.5 web server. Access “Apps” menu. Under “Administrative Tools”, select “Computer Management”. In left pane, expand "Local Users and Groups" and click on "Users". Review the local users listed in the middle pane. If any local accounts are present and were created by features which have been uninstalled or are not used, this is a finding.

The IIS 8.5 web server must be reviewed on a regular basis to remove any Operating System features, utility programs, plug-ins, and modules not necessary for operation.

Finding ID
IISW-SV-000123
Rule ID
SV-91405r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000080
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

Just as running unneeded services and protocols is a danger to the web server at the lower levels of the OSI model, running unneeded utilities and programs is also a danger at the application layer of the OSI model. Office suites, development tools, and graphical editors are examples of such programs that are troublesome. Individual productivity tools have no legitimate place or use on an enterprise, production web server and they are also prone to their own security risks. The web server installation process must provide options allowing the installer to choose which utility programs, services, and modules are to be installed or removed. By having a process for installation and removal, the web server is guaranteed to be in a more stable and secure state than if these services and programs were installed and removed manually.

Fix Text

Remove all utility programs, Operating System features or modules which are installed but are not necessary for web server operation.

Check Content

Consult with the System Administrator and review all of the IIS 8.5 and Operating System features installed. Determine if any are installed which are no longer necessary for operation. If any utility programs, features or modules are installed which are not necessary for operation, this is a finding. If any unnecessary Operating System features are installed, this is a finding.

The IIS 8.5 web server must have Multipurpose Internet Mail Extensions (MIME) that invoke OS shell programs disabled.

Finding ID
IISW-SV-000124
Rule ID
SV-91407r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000081
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

Controlling what a user of a hosted application can access is part of the security posture of the web server. Any time a user can access more functionality than is needed for the operation of the hosted application poses a security issue. A user with too much access can view information that is not needed for the user's job role, or the user could use the function in an unintentional manner. A MIME tells the web server what type of program, various file types, and extensions are and what external utilities or programs are needed to execute the file type. A shell is a program that serves as the basic interface between the user and the operating system, so hosted application users must not have access to these programs. Shell programs may execute shell escapes and can then perform unauthorized activities that could damage the security posture of the web server.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under IIS, double-click the “MIME Types” icon. From the "Group by:" drop-down list, select "Content Type". From the list of extensions under "Application", remove MIME types for OS shell program extensions, to include at a minimum, the following extensions: .exe .dll .com .bat .csh Under the "Actions" pane, click "Apply".

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under IIS, double-click the “MIME Types” icon. From the "Group by:" drop-down list, select "Content Type". From the list of extensions under "Application", verify MIME types for OS shell program extensions have been removed, to include at a minimum, the following extensions: .exe .dll .com .bat .csh If any OS shell MIME types are configured, this is a finding.

The IIS 8.5 web server must have Web Distributed Authoring and Versioning (WebDAV) disabled.

Finding ID
IISW-SV-000125
Rule ID
SV-91409r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000141-WSR-000085
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

A web server can be installed with functionality that, just by its nature, is not secure. Web Distributed Authoring (WebDAV) is an extension to the HTTP protocol that, when developed, was meant to allow users to create, change, and move documents on a server, typically a web server or web share. Allowing this functionality, development, and deployment is much easier for web authors. WebDAV is not widely used and has serious security concerns because it may allow clients to modify unauthorized files on the web server.

Fix Text

Access Server Manager on the IIS 8.5 web server. Click the IIS 8.5 web server name. Click on "Manage". Select "Add Roles and Features". Click "Next" on the "Before you begin" dialog box. Select "Role-based or feature-based installation" on the "Installation Type" dialog box and click on "Next". Select the IIS 8.5 web server on the "Server Selection" dialog box. From the "Windows Features" dialog box, navigate to "World Wide Web Services" >> "Common HTTP Features". De-select "WebDAV Publishing" and click "Next" to complete removing the WebDAV Publishing feature from the IIS 8.5 web server.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Review the features listed under the “IIS" section. If the "WebDAV Authoring Rules" icon exists, this is a finding.

Java software installed on a production IIS 8.5 web server must be limited to .class files and the Java Virtual Machine.

Finding ID
IISW-SV-000130
Rule ID
SV-91413r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000206-WSR-000128
CCI
CCI-001166
Target Key
(None)
Documentable
No
Discussion

Mobile code in hosted applications allows the developer to add functionality and displays to hosted applications that are fluid, as opposed to a static web page. The data presentation becomes more appealing to the user, is easier to analyze, and navigation through the hosted application and data is much less complicated. Some mobile code technologies in use in today's applications are: Java, JavaScript, ActiveX, PDF, Postscript, Shockwave movies, Flash animations, and VBScript. The DoD has created policies that define the usage of mobile code on DoD systems. The usage restrictions and implementation guidance apply to both the selection and use of mobile code installed on organizational servers and mobile code downloaded and executed on individual workstations. Source code for a Java program is, many times, stored in files with either .java or .jpp file extensions. From the .java and .jpp files the Java compiler produces a binary file with an extension of .class. The .java or .jpp file could therefore reveal sensitive information regarding an application's logic and permissions to resources on the server.

Fix Text

Remove all files from the web server with both .java and .jpp extensions.

Check Content

Search the system for files with either .java or .jpp extensions. If files with .java or .jpp extensions are found, this is a finding.

IIS 8.5 Web server accounts accessing the directory tree, the shell, or other operating system functions and utilities must only be administrative accounts.

Finding ID
IISW-SV-000131
Rule ID
SV-91415r1_rule
Severity
Cat I
CCE
(None)
Group Title
SRG-APP-000211-WSR-000030
CCI
CCI-001082
Target Key
(None)
Documentable
No
Discussion

As a rule, accounts on a web server are to be kept to a minimum. Only administrators, web managers, developers, auditors, and web authors require accounts on the machine hosting the web server. This is in addition to the anonymous web user account. The resources to which these accounts have access must also be closely monitored and controlled. Only the SA needs access to all the system’s capabilities, while the web administrator and associated staff require access and control of the web content and web server configuration files. The anonymous web user account must not have access to system resources as that account could then control the server.

Fix Text

Ensure non-administrators are not allowed access to the directory tree, the shell, or other operating system functions and utilities. All non-administrator access to shell scripts and operating system functions must be mission essential and documented.

Check Content

Obtain a list of the user accounts with access to the system, including all local and domain accounts. Review the privileges to the web server for each account. Verify with the system administrator or the ISSO that all privileged accounts are mission essential and documented. Verify with the system administrator or the ISSO that all non-administrator access to shell scripts and operating system functions are mission essential and documented. If undocumented privileged accounts are found, this is a finding. If undocumented non-administrator access to shell scripts and operating system functions are found, this is a finding.

The IIS 8.5 web server must separate the hosted applications from hosted web server management functionality.

Finding ID
IISW-SV-000132
Rule ID
SV-91417r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000211-WSR-000129
CCI
CCI-001082
Target Key
(None)
Documentable
No
Discussion

The separation of user functionality from web server management can be accomplished by moving management functions to a separate IP address or port. To further separate the management functions, separate authentication methods and certificates should be used. By moving the management functionality, the possibility of accidental discovery of the management functions by non-privileged users during hosted application use is minimized.

Fix Text

Develop a method to manage the hosted applications, either by moving its management functions off of the IIS 8.5 web server or by accessing the application's management via a uniquely assigned IP address.

Check Content

Review the IIS 8.5 web server configuration with the System Administrator. Determine if the IIS 8.5 web server hosts any applications. If the IIS 8.5 web server does not host any applications, this is Not Applicable. If the IIS 8.5 web server hosts applications, review the application's management functionality and authentication methods with the System Administrator to determine if the management of the application is accomplished with the same functions and authentication methods as the web server management. If the IIS 8.5 web server management and the application's management functionality is not separated, this is a finding.

The IIS 8.5 web server must augment re-creation to a stable and known baseline.

Finding ID
IISW-SV-000136
Rule ID
SV-91425r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000225-WSR-000074
CCI
CCI-001190
Target Key
(None)
Documentable
No
Discussion

Making certain that the web server has not been updated by an unauthorized user is always a concern. Adding patches, functions, and modules that are untested and not part of the baseline opens the possibility for security risks. The web server must offer, and not hinder, a method that allows for the quick and easy reinstallation of a verified and patched baseline to guarantee the production web server is up-to-date and has not been modified to add functionality or expose security risks. When the web server does not offer a method to roll back to a clean baseline, external methods, such as a baseline snapshot or virtualizing the web server, can be used.

Fix Text

Prepare documentation for disaster recovery methods for the IIS 8.5 web server in the event of the necessity for rollback. Document and test the disaster recovery methods designed.

Check Content

Interview the System Administrator for the IIS 8.5 web server. Ask for documentation on the disaster recovery methods tested and planned for the IIS 8.5 web server in the event of the necessity for rollback. If documentation for a disaster recovery has not been established, this is a finding.

Directory Browsing on the IIS 8.5 web server must be disabled.

Finding ID
IISW-SV-000138
Rule ID
SV-91429r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000251-WSR-000157
CCI
CCI-001310
Target Key
(None)
Documentable
No
Discussion

Directory browsing allows the contents of a directory to be displayed upon request from a web client. If directory browsing is enabled for a directory in IIS, users could receive a web page listing the contents of the directory. If directory browsing is enabled the risk of inadvertently disclosing sensitive content is increased.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Directory Browsing" icon. Under the "Actions" pane click "Disabled". Under the "Actions" pane, click "Apply".

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "Directory Browsing" icon. Under the “Actions” pane verify "Directory Browsing" is disabled. If “Directory Browsing” is not disabled, this is a finding.

Remote access to the IIS 8.5 web server must follow access policy or work in conjunction with enterprise tools designed to enforce policy requirements.

Finding ID
IISW-SV-000141
Rule ID
SV-91435r1_rule
Severity
Cat I
CCE
(None)
Group Title
SRG-APP-000315-WSR-000003
CCI
CCI-002314
Target Key
(None)
Documentable
No
Discussion

Logging into a web server remotely using an unencrypted protocol or service when performing updates and maintenance is a major risk. Data, such as user account, is transmitted in plaintext and can easily be compromised. When performing remote administrative tasks, a protocol or service that encrypts the communication channel must be used.

Fix Text

Ensure the web server administration is only performed over a secure path.

Check Content

If web administration is performed at the console, this check is Not Applicable. If web administration is performed remotely the following checks will apply. If administration of the server is performed remotely, it will only be performed securely by system administrators. If website administration or web application administration has been delegated, those users will be documented and approved by the ISSO. Remote administration must be in compliance with any requirements contained within the Windows Server STIGs, and any applicable network STIGs. Remote administration of any kind will be restricted to documented and authorized personnel. All users performing remote administration must be authenticated. All remote sessions will be encrypted and they will utilize FIPS 140-2-approved protocols. FIPS 140-2-approved TLS versions include TLS V1.1 or greater. Review with site management how remote administration, if applicable, is configured on the website. If remote management meets the criteria listed above, this is not a finding. If remote management is utilized and does not meet the criteria listed above, this is a finding.

The IIS 8.5 web server must provide the capability to immediately disconnect or disable remote access to the hosted applications.

Finding ID
IISW-SV-000143
Rule ID
SV-91439r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000316-WSR-000170
CCI
CCI-002322
Target Key
(None)
Documentable
No
Discussion

During an attack on the web server or any of the hosted applications, the system administrator may need to disconnect or disable access by users to stop the attack. The web server must provide a capability to disconnect users to a hosted application without compromising other hosted applications unless deemed necessary to stop the attack. Methods to disconnect or disable connections are to stop the application service for a specified hosted application, stop the web server, or block all connections through web server access list. The web server capabilities used to disconnect or disable users from connecting to hosted applications and the web server must be documented to make certain that, during an attack, the proper action is taken to conserve connectivity to any other hosted application if possible and to make certain log data is conserved for later forensic analysis.

Fix Text

Prepare documented procedures for shutting down an IIS 8.5 website in the event of an attack. The procedure should, at a minimum, provide the following steps: Determine the respective website for the application at risk of an attack. Access the IIS 8.5 web server IIS Manager. Select the respective website. In the "Actions" pane, under "Manage Website", click on "Stop". If necessary, stop all websites. If necessary, stop the IIS 8.5 web server by selecting the web server in the IIS Manager. In the "Actions" pane, under "Manage Server", click on "Stop".

Check Content

Interview the System Administrator and Web Manager. Ask for documentation for the IIS 8.5 web server administration. Verify there are documented procedures for shutting down an IIS 8.5 website in the event of an attack. The procedure should, at a minimum, provide the following steps: Determine the respective website for the application at risk of an attack. Access the IIS 8.5 web server IIS Manager. Select the respective website. In the "Actions" pane, under "Manage Website", click on "Stop". If necessary, stop all websites. If necessary, stop the IIS 8.5 web server by selecting the web server in the IIS Manager. In the "Actions" pane, under "Manage Server", click on "Stop". If the web server is not capable of or cannot be configured to disconnect or disable remote access to the hosted applications when necessary, this is a finding.

IIS 8.5 web server system files must conform to minimum file permission requirements.

Finding ID
IISW-SV-000144
Rule ID
SV-91441r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000340-WSR-000029
CCI
CCI-002235
Target Key
(None)
Documentable
No
Discussion

This check verifies the key web server system configuration files are owned by the SA or the web administrator controlled account. These same files that control the configuration of the web server, and thus its behavior, must also be accessible by the account running the web service. If these files are altered by a malicious user, the web server would no longer be under the control of its managers and owners; properties in the web server configuration could be altered to compromise the entire server platform.

Fix Text

Open Explorer and navigate to the inetpub directory. Right-click inetpub and select “Properties”. Click the "Security" tab. Set the following permissions: SYSTEM: Full control Administrators: Full control TrustedInstaller: Full control ALL APPLICATION PACKAGES (built-in security group): Read and execute Users: Read and execute, list folder contents Creator/Owner: special permissions to subkeys

Check Content

Open Explorer and navigate to the inetpub directory. Right-click inetpub and select “Properties”. Click the "Security" tab. Verify the permissions for the following users; if the permissions are less restrictive, this is a finding. System: Full control Administrators: Full control TrustedInstaller: Full control ALL APPLICATION PACKAGES (built-in security group): Read and execute Users: Read and execute, list folder contents Creator/Owner: Special permissions to subkeys

The IIS 8.5 web server must use a logging mechanism that is configured to allocate log record storage capacity large enough to accommodate the logging requirements of the IIS 8.5 web server.

Finding ID
IISW-SV-000145
Rule ID
SV-91443r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000357-WSR-000150
CCI
CCI-001849
Target Key
(None)
Documentable
No
Discussion

In order to make certain that the logging mechanism used by the web server has sufficient storage capacity in which to write the logs, the logging mechanism needs to be able to allocate log record storage capacity. The task of allocating log record storage capacity is usually performed during initial installation of the logging mechanism. The system administrator will usually coordinate the allocation of physical drive space with the web server administrator along with the physical location of the partition and disk. Refer to NIST SP 800-92 for specific requirements on log rotation and storage dependent on the impact of the web server.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "IIS" double-click on the "Logging" icon. If necessary, in the "Logging" configuration box, re-designate a log path to a location able to house the logs. Under "Log File Rollover", de-select the "Do not create new log files" setting. Configure a schedule to rollover log files on a regular basis.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "IIS" double-click on the "Logging" icon. In the "Logging" configuration box, determine the "Directory:" to which the "W3C" logging is being written. Confirm with the System Administrator that the designated log path is of sufficient size to maintain the logging. Under "Log File Rollover", verify the "Do not create new log files" is not selected. Verify a schedule is configured to rollover log files on a regular basis. Consult with the System Administrator to determine if there is a documented process for moving the log files off of the IIS 8.5 web server to another logging device. If the designated logging path device is not of sufficient space to maintain all log files and there is not a schedule to rollover files on a regular basis, this is a finding.

Access to web administration tools must be restricted to the web manager and the web managers designees.

Finding ID
IISW-SV-000147
Rule ID
SV-91445r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000380-WSR-000072
CCI
CCI-002385
Target Key
(None)
Documentable
No
Discussion

A web server can be modified through parameter modification, patch installation, upgrades to the web server or modules, and security parameter changes. With each of these changes, there is the potential for an adverse effect such as a DoS, web server instability, or hosted application instability. To limit changes to the web server and limit exposure to any adverse effects from the changes, files such as the web server application files, libraries, and configuration files must have permissions and ownership set properly to only allow privileged users access. The key web service administrative and configuration tools must only be accessible by the web server staff. All users granted this authority will be documented and approved by the ISSO. Access to the IIS Manager will be limited to authorized users and administrators. Satisfies: SRG-APP-000380-WSR-000072, SRG-APP-000435-WSR-000147, SRG-APP-000033-WSR-000169

Fix Text

Restrict access to the web administration tool to only the web manager and the web manager’s designees.

Check Content

Right-click InetMgr.exe, then click “Properties” from the “Context” menu. Select the "Security" tab. Review the groups and user names. The following account may have Full control privileges: TrustedInstaller Web Managers Web Manager designees The following accounts may have read and execute, or read permissions: Non Web Manager Administrators ALL APPLICATION PACKAGES (built-in security group) SYSTEM Users Specific users may be granted read and execute and read permissions. Compare the local documentation authorizing specific users, against the users observed when reviewing the groups and users. If any other access is observed, this is a finding.

The IIS 8.5 web server must not be running on a system providing any other role.

Finding ID
IISW-SV-000148
Rule ID
SV-91447r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000383-WSR-000175
CCI
CCI-001762
Target Key
(None)
Documentable
No
Discussion

Web servers provide numerous processes, features, and functionalities that utilize TCP/IP ports. Some of these processes may be deemed unnecessary or too unsecure to run on a production system. The web server must provide the capability to disable or deactivate network-related services that are deemed to be non-essential to the server mission, are too unsecure, or are prohibited by the PPSM CAL and vulnerability assessments.

Fix Text

Remove all unapproved programs and roles from the production web server.

Check Content

Review programs installed on the OS. Open Control Panel. Open Programs and Features. The following programs may be installed without any additional documentation: Administration Pack for IIS IIS Search Engine Optimization Toolkit Microsoft .NET Framework version 3.5 SP1 or greater Microsoft Web Platform Installer version 3.x or greater Virtual Machine Additions Review the installed programs, if any programs are installed other than those listed above, this is a finding. Note: If additional software is needed and has supporting documentation signed by the ISSO, this is not a finding.

The Internet Printing Protocol (IPP) must be disabled on the IIS 8.5 web server.

Finding ID
IISW-SV-000149
Rule ID
SV-91449r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000383-WSR-000175
CCI
CCI-001762
Target Key
(None)
Documentable
No
Discussion

The use of Internet Printing Protocol (IPP) on an IIS web server allows client’s access to shared printers. This privileged access could allow remote code execution by increasing the web servers attack surface. Additionally, since IPP does not support SSL, it is considered a risk and will not be deployed.

Fix Text

Click “Start”, then click “Administrative Tools”, and then click “Server Manager”. Expand the roles node, then right-click “Print Services”, and then select “Remove Roles Services”. If the Internet Printing option is checked, clear the check box, click “Next”, and then click “Remove” to complete the wizard.

Check Content

If the Print Services role and the Internet Printing role are not installed, this check is Not Applicable. Navigate to the following directory: %windir%\web\printers If this folder exists, this is a finding. Determine whether Internet Printing is enabled: Click “Start”, then click “Administrative Tools”, and then click “Server Manager”. Expand the roles node, then right-click “Print Services”, and then select “Remove Roles Services”. If the Internet Printing option is enabled, this is a finding.

The IIS 8.5 web server must be tuned to handle the operational requirements of the hosted application.

Finding ID
IISW-SV-000151
Rule ID
SV-91451r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000435-WSR-000148
CCI
CCI-002385
Target Key
(None)
Documentable
No
Discussion

A Denial of Service (DoS) can occur when the web server is so overwhelmed that it can no longer respond to additional requests. A web server not properly tuned may become overwhelmed and cause a DoS condition even with expected traffic from users. To avoid a DoS, the web server must be tuned to handle the expected traffic for the hosted applications.

Fix Text

Access the IIS 8.5 web server registry. Verify the following keys are present and configured. The required setting depends upon the requirements of the application. These settings have to be explicitly configured to show a conscientious tuning has been made. Navigate to HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters\ Configure the following registry keys to levels to accommodate the hosted applications. "URIEnableCache" "UriMaxUriBytes" "UriScavengerPeriod"

Check Content

If the IIS 8.5 web server is not hosting any applications, this is Not Applicable. If the IIS 8.5 web server is hosting applications, consult with the System Administrator to determine risk analysis performed when application was written and deployed to the IIS 8.5 web server. Obtain documentation on the configuration. Verify, at a minimum, the following tuning settings in the registry. Access the IIS 8.5 web server registry. Verify the following keys are present and configured. The required setting depends upon the requirements of the application. Recommended settings are not provided as these settings have to be explicitly configured to show a conscientious tuning has been made. Navigate to HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters\ "URIEnableCache" "UriMaxUriBytes" "UriScavengerPeriod" If explicit settings are not configured for "URIEnableCache", "UriMaxUriBytes" and "UriScavengerPeriod", this is a finding.

IIS 8.5 web server session IDs must be sent to the client using TLS.

Finding ID
IISW-SV-000152
Rule ID
SV-91453r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000439-WSR-000152
CCI
CCI-002418
Target Key
(None)
Documentable
No
Discussion

The HTTP protocol is a stateless protocol. To maintain a session, a session identifier is used. The session identifier is a piece of data that is used to identify a session and a user. If the session identifier is compromised by an attacker, the session can be hijacked. By encrypting the session identifier, the identifier becomes more difficult for an attacker to hijack, decrypt, and use before the session has expired.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "Management" section, double-click the "Configuration Editor" icon. From the "Section:" drop-down list, select 'system.webServer/asp". Expand the "session" section. Select "True" for the "keepSessionIdSecure" setting. Select "Apply" from the "Actions" pane.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Under "Management" section, double-click the "Configuration Editor" icon. From the "Section:" drop-down list, select “system.webServer/asp". Expand the "session" section. Verify the "keepSessionIdSecure" is set to "True". If the "keepSessionIdSecure" is not set to "True", this is a finding.

A web server must maintain the confidentiality of controlled information during transmission through the use of an approved TLS version.

Finding ID
IISW-SV-000154
Rule ID
SV-91457r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000439-WSR-000156
CCI
CCI-002418
Target Key
(None)
Documentable
No
Discussion

Transport Layer Security (TLS) is a required transmission protocol for a web server hosting controlled information. The use of TLS provides confidentiality of data in transit between the web server and client. FIPS 140-2-approved TLS versions must be enabled and non-FIPS-approved SSL versions must be disabled. NIST SP 800-52 defines the approved TLS versions for government applications.

Fix Text

Configure the web server to use an approved TLS version according to NIST SP 800-52 and to disable all non-approved versions.

Check Content

Review the web server documentation and deployed configuration to determine which version of TLS is being used. If the TLS version is not TLS 1.1 or higher, according to NIST SP 800-52, or if non-FIPS-approved algorithms are enabled, this is a finding.

All accounts installed with the IIS 8.5 web server software and tools must have passwords assigned and default passwords changed.

Finding ID
IISW-SV-000156
Rule ID
SV-91461r1_rule
Severity
Cat I
CCE
(None)
Group Title
SRG-APP-000516-WSR-000079
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

During installation of the web server software, accounts are created for the web server to operate properly. The accounts installed can have either no password installed or a default password, which will be known and documented by the vendor and the user community. The first things an attacker will try when presented with a logon screen are the default user identifiers with default passwords. Installed applications may also install accounts with no password, making the logon even easier. Once the web server is installed, the passwords for any created accounts should be changed and documented. The new passwords must meet the requirements for all passwords, i.e., upper/lower characters, numbers, special characters, time until change, reuse policy, etc. Service accounts or system accounts that have no logon capability do not need to have passwords set or changed.

Fix Text

Access the IIS 8.5 web server. Access Apps menu. Under Administrative Tools, select Computer Management. In left pane, expand "Local Users and Groups" and click on "Users". Change passwords for any local accounts are present and are used by IIS 8.5 verify with System Administrator that default passwords have been changed. Develop an internal process for changing passwords on a regular basis.

Check Content

Access the IIS 8.5 web server. Access Apps menu. Under Administrative Tools, select Computer Management. In left pane, expand "Local Users and Groups" and click on "Users". Review the local users listed in the middle pane. If any local accounts are present and are used by IIS 8.5 verify with System Administrator that default passwords have been changed. If passwords have not been changed from the default, this is a finding.

The File System Object component must be disabled on the IIS 8.5 web server.

Finding ID
IISW-SV-000157
Rule ID
SV-91463r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000516-WSR-000174
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

Some Component Object Model (COM) components are not required for most applications and should be removed if possible. Most notably, consider disabling the File System Object component; however, this will also remove the Dictionary object. Be aware some programs may require this component (e.g., Commerce Server), so it is highly recommended this be tested completely before implementing on the production web server.

Fix Text

Run the following command, with administrator privileges, to unregister the File System Object: regsvr32 scrrun.dll /u.

Check Content

Locate the HKEY_CLASSES_ROOT\CLSID\{0D43FE01-F093-11CF-8940-00A0C9054228} registry key. If the key exist, the File System Object component is enabled. If the File System Object component is enabled and is not required for operations, this is a finding. Note: If the File System Object component is required for operations and has supporting documentation signed by the ISSO, this is not a finding.

Unspecified file extensions on a production IIS 8.5 web server must be removed.

Finding ID
IISW-SV-000158
Rule ID
SV-91465r1_rule
Severity
Cat II
CCE
(None)
Group Title
SRG-APP-000516-WSR-000174
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

By allowing unspecified file extensions to execute, the web servers attack surface is significantly increased. This increased risk can be reduced by only allowing specific ISAPI extensions or CGI extensions to run on the web server.

Fix Text

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "ISAPI and CGI restrictions" icon. Click "Edit Feature Settings". Remove the check from the "Allow unspecified CGI modules" and the "Allow unspecified ISAPI modules" check boxes. Click OK.

Check Content

Open the IIS 8.5 Manager. Click the IIS 8.5 web server name. Double-click the "ISAPI and CGI restrictions" icon. Click “Edit Feature Settings". Verify the "Allow unspecified CGI modules" and the "Allow unspecified ISAPI modules" check boxes are NOT checked. If either or both of the "Allow unspecified CGI modules" and the "Allow unspecified ISAPI modules" check boxes are checked, this is a finding.