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Microsoft Excel 2013 STIG

Version 1 Release 75
2018-04-272016-10-28
U_MS_icrosoftExcel_2013_STIG_V1R75_Manual-xccdf.xml
The Microsoft Excel 2013 Security Technical Implementation Guide (STIG) is published as a tool to improve the security of Department of Defense (DoD) information systems. Comments or proposed revisions to this document should be sent via e-mail to the following address: disa.stig_spt@mail.mil.

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  • Updated 46
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  • Removed 1

Vulnerabilities (47)

Removed

V-72831

Macros must be blocked from running in Office 2013 files from the Internet.

Finding ID
DTOO600
Rule ID
SV-87483r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO600 - Macros must be blocked from running in Office 2013 files from the Internet.
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

This policy setting allows you to block macros from running in Office files that come from the Internet. If you enable this policy setting, macros are blocked from running, even if "Enable all macros" is selected in the Macro Settings section of the Trust Center. Also, instead of having the choice to "Enable Content", users will receive a notification that macros are blocked from running. If the Office file is saved to a trusted location or was previously trusted by the user, macros will be allowed to run. If you disable or don't configure this policy setting, the settings configured in the Macro Settings section of the Trust Center determine whether macros run in Office files that come from the Internet.

Fix Text

Set the policy value for User Configuration >> Administrative Templates >> Microsoft Excel 2013 >> Excel Options >> Security >> Trust Center "Block macros from running in Office files from the Internet" to "Enabled".

Check Content

Verify the policy value for User Configuration >> Administrative Templates >> Microsoft Excel 2013 >> Excel Options >> Security >> Trust Center "Block macros from running in Office files from the Internet" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value blockcontentexecutionfrominternet is REG_DWORD = 1, this is not a finding.

Disabling of user name and password syntax from being used in URLs must be enforced.

Finding ID
DTOO104
Rule ID
SV-53609r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO104 - Disable user name and password
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

The Uniform Resource Locator (URL) standard allows user authentication to be included in URL strings in the form http://username:password@example.com. A malicious user might use this URL syntax to create a hyperlink that appears to open a legitimate website but actually opens a deceptive (spoofed) website. For example, the URL http://www.wingtiptoys.com@example.com appears to open http://www.wingtiptoys.com but actually opens http://example.com. To protect users from such attacks, Internet Explorer usually blocks any URLs using this syntax. This functionality can be controlled separately for instances of Internet Explorer spawned by Office applications (for example, if a user clicks a link in an Office document or selects a menu option that loads a web page). If user names and passwords in URLs are allowed, users could be diverted to dangerous web pages, which could pose a security risk.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Disable user name and password" to "Enabled" and place a check in the 'excel.exe' check box.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Disable user name and password" is set to "Enabled" and a check in the 'excel.exe' check box is set to present. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_HTTP_USERNAME_PASSWORD_DISABLE Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Internet Explorer Bind to Object functionality must be enabled.

Finding ID
DTOO111
Rule ID
SV-53618r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO111 - Enable IE Bind to Object
CCI
CCI-001695
Target Key
(None)
Documentable
No
Discussion

Internet Explorer performs a number of safety checks before initializing an ActiveX control. It will not initialize a control if the kill bit for the control is set in the registry, or if the security settings for the zone in which the control is located do not allow it to be initialized. This functionality can be controlled separately for instances of Internet Explorer spawned by Office applications (for example, if a user clicks a link in an Office document or selects a menu option that loads a Web page). A security risk could occur if potentially dangerous controls are allowed to load.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Bind to Object" to "Enabled" and place a check in the 'excel.exe' check box.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Bind to Object" is set to "Enabled" and a check in the 'excel.exe' check box is set to present. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_SAFE_BINDTOOBJECT Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

The Saved from URL mark must be selected to enforce Internet zone processing.

Finding ID
DTOO117
Rule ID
SV-53629r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO117 - Saved from URL
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

Typically, when Internet Explorer loads a web page from a Universal Naming Convention (UNC) share that contains a Mark of the Web (MOTW) comment, indicating the page was saved from a site on the Internet, Internet Explorer runs the page in the Internet security zone instead of the less restrictive Local Intranet security zone. This functionality can be controlled separately for instances of Internet Explorer spawned by Office applications (for example, if a user clicks a link in an Office document or selects a menu option that loads a web page). If Internet Explorer does not evaluate the page for a MOTW, potentially dangerous code could be allowed to run.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Saved from URL" to "Enabled" and place a check in the 'excel.exe' check box.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Saved from URL" is set to "Enabled" and a check in the 'excel.exe' check box is set to present. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_UNC_SAVEDFILECHECK Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Navigation to URLs embedded in Office products must be blocked.

Finding ID
DTOO123
Rule ID
SV-53679r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO123-Block Navigation to URL from Office
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

To protect users from attacks, Internet Explorer usually does not attempt to load malformed URLs. This functionality can be controlled separately for instances of Internet Explorer spawned by Office applications (for example, if a user clicks a link in an Office document or selects a menu option that loads a Web page). If Internet Explorer attempts to load a malformed URL, a security risk could occur.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Navigate URL" to "Enabled" and place a check in the 'excel.exe' check box.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Navigate URL" is set to "Enabled" and a check in the 'excel.exe' check box is set to present. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_VALIDATE_NAVIGATE_URL Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding

Responsibility

System Administrator

Links that invoke instances of Internet Explorer from within an Office product must be blocked.

Finding ID
DTOO129
Rule ID
SV-53683r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO129 - Block Pop-Ups
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

The "Pop-up Blocker" feature in Internet Explorer can be used to block most unwanted pop-up and pop-under windows from appearing. This functionality can be controlled separately for instances of Internet Explorer spawned by Office applications (for example, if a user clicks a link in an Office document or selects a menu option that loads a web page). If the Pop-up Blocker is disabled, disruptive and potentially dangerous pop-up windows could load and present a security risk.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Block popups" to "Enabled" and select 'excel.exe'.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Block popups" is set to "Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_WEBOC_POPUPMANAGEMENT Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Trust Bar Notifications for unsigned application add-ins must be blocked.

Finding ID
DTOO131
Rule ID
SV-53711r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO131 - Trust Bar Notifications
CCI
CCI-001749
Target Key
(None)
Documentable
No
Discussion

If an application is configured to require all add-ins to be signed by a trusted publisher, any unsigned add-ins the application loads will be disabled and the application will display the Trust Bar at the top of the active window. The Trust Bar contains a message informing users about the unsigned add-in. If a user is allowed to make the determination to allow an unsigned add-in, it increases the risk of malicious code being introduced onto the user's computer or the network.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Disable Trust Bar Notification for unsigned application add-ins and block them" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Disable Trust Bar Notification for unsigned application add-ins and block them" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value NoTBPromptUnsignedAddin is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

The opening of pre-release versions of file formats new to Excel 2013 through the Compatibility Pack for Office 2013 and Excel 2013 Converter must be blocked.

Finding ID
DTOO210
Rule ID
SV-53824r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO210 - Block opening of pre-release versions
CCI
CCI-001764
Target Key
(None)
Documentable
No
Discussion

By default, users are prompted to update automatic links.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Office 2013 -> Office 2013 Converters -> "Block opening of pre-release versions of file formats new to Excel 2013 through the Compatibility Pack for Office 2013 and Excel 2013 Converter" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Office 2013 -> Office 2013 Converters -> "Block opening of pre-release versions of file formats new to Excel 2013 through the Compatibility Pack for Office 2013 and Excel 2013 Converter" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\Microsoft\office\15.0\excel\security\fileblock Criteria: If the value excel12betafilesfromconverters is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

All automatic loading from trusted locations must be disabled.

Finding ID
DTOO133
Rule ID
SV-53723r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO133-Disable all trusted locations
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

Trusted locations specified in the Trust Center are used to define file locations assumed to be safe. Content, code, and add-ins are allowed to load from trusted locations with a minimal amount of security, without prompting the users for permission. If a dangerous file is opened from a trusted location, it will not be subject to standard security measures and could harm users' computers or data. By default, files located in trusted locations (those specified in the Trust Center) are assumed to be safe.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Trusted Locations "Disable all trusted locations" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Trusted Locations "Disable all trusted locations" is set to Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\trusted locations Criteria: If the value AllLocationsDisabled is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

The scanning of encrypted macros in open XML documents must be enforced.

Finding ID
DTOO142
Rule ID
SV-53810r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO142 - Force Scan Encr. Macros in open XML
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

When an Office Open XML document (Word, Excel, and PowerPoint) is rights-managed, or password-protected, any macros embedded in the document are encrypted along with the rest of the contents. By default, these encrypted macros will be disabled unless they are scanned by antivirus software immediately before being loaded. If this default configuration is modified, Office products will not require encrypted macros to be scanned before loading. They will be handled as specified by the Office System macro security settings, which can cause macro viruses to load undetected and lead to data loss or reduced application functionality.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Scan encrypted macros in Excel Open XML workbooks" to "Enabled: Scan encrypted macros (default)".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Scan encrypted macros in Excel Open XML workbooks" is set to "Enabled: Scan encrypted macros (default)". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value ExcelBypassEncryptedMacroScan is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Disallowance of trusted locations on the network must be enforced.

Finding ID
DTOO134
Rule ID
SV-53724r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO134 - Trusted locations on computer
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

Files located in trusted locations and specified in the Trust Center are typically assumed to be safe. Content, code, and add-ins are allowed to load from trusted locations with minimal security and without prompting the user for permission. By default, users can specify "Trusted Locations" on network shares, or in other remote locations not under their direct control, by selecting the "Allow Trusted Locations on my network" (not recommended) check box in the "Trusted Locations" section of the Trust Center. If a dangerous file is opened from a trusted location, it will not be subject to typical security measures and could affect users' computers or data.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Trusted Locations "Allow Trusted Locations on the network" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Trusted Locations "Allow Trusted Locations on the network" is set to Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\trusted locations Criteria: If the value AllowNetworkLocations is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

The Save commands default file format must be configured.

Finding ID
DTOO139
Rule ID
SV-53726r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO139 - Save files default format
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

When users create new Excel files, Excel 2013 saves them in the new *.xlsx format. Ensure this setting is enabled to specify all new files are created in Excel 2013. If a new file is created in an earlier format, some users may not be able to open or use the file, or they may choose a format that is less secure than the Excel 2013 format. Users can still select a specific format when they save files, but they cannot change the default of this setting from the "Excel Options" dialog box. This enforced user behavior ensures any change to the file format requires additional deliberate user interaction.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "default file format" to "Enabled (Excel Workbook *.xlsx)".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "default file format" is set to "Enabled (Excel Workbook *.xlsx)". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\options Criteria: If the value DefaultFormat is REG_DWORD = 0x00000033(hex) or 51 (Decimal), this is not a finding.

Responsibility

System Administrator

Trust access for VBA must be disallowed.

Finding ID
DTOO146
Rule ID
SV-53813r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO146-Disable Trust access to VB Project Macros
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

VSTO projects require access to the Visual Basic for Applications project system in Excel, PowerPoint, and Word, even though the projects do not use Visual Basic for Applications. Design-time support of controls in both Visual Basic and C# projects depends on the Visual Basic for Applications project system in Word and Excel. By default, Excel, Word, and PowerPoint do not allow automation clients to have programmatic access to VBA projects. Users can enable this by selecting the Trust access to the VBA project object model in the Macro Settings section of the Trust Center. However, doing so allows macros in any documents the user opens to access the core Visual Basic objects, methods, and properties, which represents a potential security hazard.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Trust access to Visual Basic Project" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Trust access to Visual Basic Project" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value AccessVBOM is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Warning Bar settings for VBA macros must be configured.

Finding ID
DTOO304
Rule ID
SV-53838r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO304 - VBA Macro Warning settings
CCI
CCI-000381
Target Key
(None)
Documentable
No
Discussion

When users open files containing VBA macros, applications open the files with the macros disabled and displays the Trust Bar with a warning that macros are present and have been disabled. Users may then enable these macros by clicking "Options" on the Trust Bar and selecting the option to enable them. Disabling or not configuring this setting may allow dangerous macros to become active on user computers or the network.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "VBA Macro Notification Settings" to "Enabled: Disable all with notification".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "VBA Macro Notification Settings" is set to "Enabled: Disable all with notification". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value VBAWarnings is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

File types must be configured to provide mismatch warnings

Finding ID
DTOO143
Rule ID
SV-53811r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO143 - Force File Extension to match type
CCI
CCI-001243
Target Key
(None)
Documentable
No
Discussion

Excel can load files with extensions that do not match the files' type. For example, if a comma-separated values (CSV) file named example.csv is renamed example.xls, Excel can properly load it as a CSV file. Some attacks target specific file formats. If Excel is allowed to load files with extensions that do not match their file types, a malicious individual can deceive users into loading dangerous files that have incorrect extensions. By default, if users attempt to open files with the wrong extension, Excel opens the file and displays a warning that the file type is not what Excel expected.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Force file extension to match file type" to "Enabled (Allow different, but warn)".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Force file extension to match file type" is set to "Enabled (Allow different, but warn)". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value ExtensionHardening is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Internet links and Network UNCs created as embedded hyperlinks must be prevented.

Finding ID
DTOO138
Rule ID
SV-53725r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO138 - Internet and Network Path hyperlinks
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

When users type a string of characters, Excel recognizes as a Uniform Resource Locator (URL) or Uniform Naming Convention (UNC) path to a resource on the Internet or a local network, Excel will transform it into a hyperlink. Clicking the hyperlink opens it in the configured default web browser or the appropriate application. This functionality can enable users to accidentally create links to dangerous or restricted resources, which could create a security risk.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Proofing -> Autocorrect Options "Internet and network paths as hyperlinks" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Proofing -> Autocorrect Options "Internet and network paths as hyperlinks" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\options If the value AutoHyperlink is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Automatic republish to web pages must be disallowed.

Finding ID
DTOO140
Rule ID
SV-53731r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO140 - Disable AutoRepublish
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

If users choose to publish Excel data to a static web page and enable the AutoRepublish feature, Excel saves a copy of the data to the web page every time the user saves the workbook. If the page is on a web server, anyone who has access to the page will be able to see the updated data after every save, which can lead to the undesired disclosure of sensitive or incorrect information. By default, a message dialog box displays every time the user saves a published workbook when AutoRepublish is enabled. From this dialog box, the user can disable AutoRepublish temporarily or permanently, or select "Do not show this message again" to prevent the dialog box from appearing after every save. If the user selects "Do not show this message again", Excel will continue to automatically republish the data after every save without informing the user.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "Disable AutoRepublish" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "Disable AutoRepublish" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\options Criteria: If the value DisableAutoRepublish is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

The Update of automatic links setting must be configured to prompt user before allowing links to be updated.

Finding ID
DTOO150
Rule ID
SV-53815r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO150 - Automatic Link Updates
CCI
CCI-001243
Target Key
(None)
Documentable
No
Discussion

If an Excel workbook contains links to other documents and users are not prompted to approve them, the contents of the workbook might change without the users' knowledge because the linked files have changed. This has the risk of introducing corrupt or malicious content into the document. Prompting the user to update links will allow the content to be updated only with the user's knowledge.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel options -> Advanced -> "Ask to update automatic links" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel options -> Advanced -> "Ask to update automatic links" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\Microsoft\office\15.0\excel\options\binaryoptions Criteria: If the value fupdateext_78_1 is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

The AutoRepublish warning alert must be provided.

Finding ID
DTOO141
Rule ID
SV-53803r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO141 - AutoRepublish Warning Alert
CCI
CCI-000366
Target Key
(None)
Documentable
No
Discussion

AutoRepublish is a feature in Excel allowing workbooks to be automatically republished to the World Wide Web each time the workbook is saved. A number of changes might need to be made to allow the workbook to be successfully published, including the following: * External references are converted to values. * Hidden formulas become visible. * The "Set precision as displayed" option, which appears beneath the "When calculating this workbook" heading in the "Advanced" section of the "Excel Options" dialog box, is no longer available. These types of changes can mean the version on the web page might not be the same as the Excel file. By default, a message dialog box appears every time the user saves a published workbook when AutoRepublish is enabled. From this dialog box, the user can disable AutoRepublish temporarily or permanently, or select "Do not show this message again" to prevent the dialog box from appearing after every save. If the user selects "Do not show this message again", Excel will continue to automatically republish the data after every save without informing the user.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "Do not show AutoRepublish warning alert" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Save "Do not show AutoRepublish warning alert" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\options Criteria: If the value DisableAutoRepublishWarning is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

The loading of images from web pages must not be allowed.

Finding ID
DTOO152
Rule ID
SV-53820r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO152 - Load pics from Web not in Excel
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

When users open web pages in Excel, Excel loads any graphics included in the pages, regardless of whether or not they were originally created in Excel. Allowing Excel to load graphics created in other programs can make Excel vulnerable to possible future zero-day attacks using graphic files as an attack vector. If such an event occurs, this setting can be used to mitigate the vulnerability.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Advanced -> Web Options -> General "Load pictures from Web pages not created in Excel" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Advanced -> Web Options -> General "Load pictures from Web pages not created in Excel" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\internet Criteria: If the value "DoNotLoadPictures" is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Macro storage must be in personal macro workbooks.

Finding ID
DTOO145
Rule ID
SV-53812r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO145 - Store macro in workbook
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

The Record Macro dialog box includes a drop-down menu allowing users to choose whether to store the new macro in the current workbook, a new workbook, or their personal macro workbook (Personal.xlsb), a hidden workbook that opens every time Excel starts. By default, Excel displays the Record Macro dialog box with "This Workbook already selected" in the drop-down menu. If a user saves a macro in the active workbook and then distributes the workbook to others, the macro is distributed along with the workbook, which could put workbook data at risk if the macro is triggered accidentally or intentionally.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Store macro in Personal Macro Workbook by default" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Store macro in Personal Macro Workbook by default" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\options\binaryoptions Criteria: If the value fGlobalSheet_37_1 is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Add-on Management functionality must be allowed.

Finding ID
DTOO126
Rule ID
SV-53681r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO126 - Add-on Management
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

Internet Explorer add-ons are pieces of code, run in Internet Explorer, to provide additional functionality. Rogue add-ons may contain viruses or other malicious code. Disabling or not configuring this setting could allow malicious code or users to become active on user computers or the network. For example, a malicious user can monitor and then use keystrokes users type into Internet Explorer. Even legitimate add-ons may demand resources, compromising the performance of Internet Explorer, and the operating systems for user computers.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Add-on Management" to "Enabled" and 'excel.exe' is checked.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Add-on Management" is set to Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_ADDON_MANAGEMENT Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Protection from zone elevation must be enforced.

Finding ID
DTOO209
Rule ID
SV-53822r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO209 - Zone Elevation Protection
CCI
CCI-001695
Target Key
(None)
Documentable
No
Discussion

Internet Explorer places restrictions on each web page users can use the browser to open. Web pages on a user's local computer have the fewest security restrictions and reside in the Local Machine zone, making this security zone a prime target for malicious users and code. Disabling or not configuring this setting could allow pages in the Internet zone to navigate to pages in the Local Machine zone to then run code to elevate privileges. This could allow malicious code or users to become active on user computers or the network.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Protection From Zone Elevation" to "Enabled" and 'excel.exe' is checked.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Protection From Zone Elevation" is set to Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_ZONE_ELEVATION Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

ActiveX Installs must be configured for proper restriction.

Finding ID
DTOO211
Rule ID
SV-53827r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO211 - Restrict ActiveX Install
CCI
CCI-002460
Target Key
(None)
Documentable
No
Discussion

Microsoft ActiveX controls allow unmanaged, unprotected code to run on the user computers. ActiveX controls do not run within a protected container in the browser like the other types of HTML or Microsoft Silverlight-based controls. Disabling or not configuring this setting does not block prompts for ActiveX control installations and these prompts display to users. This could allow malicious code to become active on user computers or the network.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Restrict ActiveX Install" to "Enabled" and 'excel.exe' is checked.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Restrict ActiveX Install" is set to Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_RESTRICT_ACTIVEXINSTALL Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

File downloads must be configured for proper restrictions.

Finding ID
DTOO132
Rule ID
SV-53713r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO132 - Restrict File Download
CCI
CCI-001169
Target Key
(None)
Documentable
No
Discussion

Disabling this setting allows websites to present file download prompts via code without the user specifically initiating the download. User preferences may also allow the download to occur without prompting or interaction with the user. Even if Internet Explorer prompts the user to accept the download, some websites abuse this functionality. Malicious websites may continually prompt users to download a file or present confusing dialog boxes to trick users into downloading or running a file. If the download occurs and it contains malicious code, the code could become active on user computers or the network.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Restrict File Download" to "Enabled" and 'excel.exe' is checked.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Restrict File Download" is set to "Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_RESTRICT_FILEDOWNLOAD Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Scripted Window Security must be enforced.

Finding ID
DTOO124
Rule ID
SV-53680r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO124 - Scripted Window Security
CCI
CCI-001695
Target Key
(None)
Documentable
No
Discussion

Malicious websites often try to confuse or trick users into giving a site permission to perform an action allowing the site to take control of the users' computers in some manner. Disabling or not configuring this setting allows unknown websites to: -Create browser windows appearing to be from the local operating system. -Draw active windows displaying outside of the viewable areas of the screen capturing keyboard input. -Overlay parent windows with their own browser windows to hide important system information, choices or prompts.

Fix Text

Set the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Scripted Window Security Restrictions" to "Enabled" and 'excel.exe' is checked.

Check Content

Verify the policy value for Computer Configuration -> Administrative Templates -> Microsoft Office 2013 (Machine) -> Security Settings -> IE Security "Scripted Window Security Restrictions" is set to "Enabled" and 'excel.exe' is checked. Procedure: Use the Windows Registry Editor to navigate to the following key: HKLM\Software\Microsoft\Internet Explorer\Main\FeatureControl\FEATURE_WINDOW_RESTRICTIONS Criteria: If the value excel.exe is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Add-ins to Office applications must be signed by a Trusted Publisher.

Finding ID
DTOO127
Rule ID
SV-53682r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO127 - Add-ins are signed by Trusted Publisher
CCI
CCI-001749
Target Key
(None)
Documentable
No
Discussion

Office 2013 applications do not, by default, check the digital signature on application add-ins before opening them. Disabling or not configuring this setting may allow an application to load a dangerous add-in. As a result, malicious code could become active on user computers or the network.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Require that application add-ins are signed by Trusted Publisher" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center "Require that application add-ins are signed by Trusted Publisher" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security Criteria: If the value RequireAddinSig is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Configuration for file validation must be enforced.

Finding ID
DTOO119
Rule ID
SV-53632r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO119 - Turn off file validation
CCI
CCI-001695
Target Key
(None)
Documentable
No
Discussion

Office File Validation helps detect and prevent a kind of exploit known as a file format attack or file fuzzing attack. File format attacks exploit the integrity of a file. They occur when someone modifies the structure of a file with the intent of adding malicious code. Usually the malicious code is run remotely and is used to elevate the privilege of restricted accounts on the computer. As a result, an attacker could gain access to a computer that they did not previously have access to. This could enable an attacker to read sensitive information from the computer's hard disk drive or install malware, such as a worm or a key logging program. The Office File Validation feature helps prevent file format attacks by scanning and validating files before they are opened. To validate files, Office File Validation compares a file's structure to a predefined file schema, which is a set of rules that determine what a readable file looks like. If Office File Validation detects that a file's structure does not follow all rules that are described in the schema, the file does not pass validation.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Turn off file validation" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security "Turn off file validation" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\filevalidation Criteria: If the value EnableOnLoad is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Open/Save actions for dBase III / IV files must be blocked.

Finding ID
DTOO122
Rule ID
SV-53678r2_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO122 - dBase III / IV files
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur during between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "dBase III / IV files" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "dBase III / IV files" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value DBaseFiles is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Dif and Sylk files must be blocked.

Finding ID
DTOO112
Rule ID
SV-53620r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO112 - Dif and Sylk files
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Dif and Sylk files" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Dif and Sylk files" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value DifandSylkFiles is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 2 macrosheets and add-in files must be blocked.

Finding ID
DTOO113
Rule ID
SV-53622r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO113 - Macrosheets and add-in files
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 2 macrosheets and add-in files" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 2 macrosheets and add-in files" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL2Macros is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 2 worksheets must be blocked.

Finding ID
DTOO114
Rule ID
SV-53624r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO114 - Excel 2 worksheets
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 2 worksheets" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 2 worksheets" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL2Worksheets is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 3 macrosheets and add-in files must be blocked.

Finding ID
DTOO115
Rule ID
SV-53626r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO115 - Excel 3 macrosheets and add-in files
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 3 macrosheets and add-in files" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 3 macrosheets and add-in files" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL3Macros is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 3 worksheets must be blocked.

Finding ID
DTOO116
Rule ID
SV-53628r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO116 - Excel 3 worksheets
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 3 worksheets" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 3 worksheets" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL3Worksheets is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 4 macrosheets and add-in files must be blocked.

Finding ID
DTOO105
Rule ID
SV-53610r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO105 - Excel 4 macrosheets and add-in files
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 macrosheets and add-in files" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 macrosheets and add-in files" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL4Macros is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 4 workbooks must be blocked.

Finding ID
DTOO106
Rule ID
SV-53611r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO106 - Excel 4 workbooks
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 workbooks" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 workbooks" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL4Workbooks is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Open/Save actions for Excel 4 worksheets must be blocked.

Finding ID
DTOO107
Rule ID
SV-53612r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO107 - Excel 4 worksheets
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 worksheets" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 4 worksheets" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL4Worksheets is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Actions for Excel 95 workbooks must be configured to edit in Protected View.

Finding ID
DTOO108
Rule ID
SV-53614r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO108 - Excel 95 workbooks
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 95 workbooks" to "Enabled: Allow editing and open in Protected View".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 95 workbooks" is set to "Enabled: Allow editing and open in Protected View". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value XL95Workbooks is REG_DWORD = 5, this is not a finding.

Responsibility

System Administrator

Actions for Excel 95-97 workbooks and templates must be configured to edit in Protected View.

Finding ID
DTOO109
Rule ID
SV-53615r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO109 - Excel 95-97 workbooks and templates
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting specifies whether users can open, view, edit, or save files saved in the specified format. Enabling block of the specified format mitigates zero-day security attacks (which are attacks that occur between the time that a vulnerability becomes publicly known and a software update or service pack is available) by temporarily preventing users from opening specific types of files and to prevent a user from opening files that have been saved in earlier and pre-release (beta) Microsoft Office formats.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 95-97 workbooks and templates" to "Enabled: Allow editing and open in Protected View".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Excel 95-97 workbooks and templates" is set to "Enabled: Allow editing and open in Protected View". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\office\15.0\excel\security\fileblock Criteria: If the value XL9597WorkbooksandTemplates is REG_DWORD = 5, this is not a finding.

Responsibility

System Administrator

Blocking as default file block opening behavior must be enforced.

Finding ID
DTOO110
Rule ID
SV-53617r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO110 - Set default file block behavior
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

Users can open, view, or edit a large number of file types in Office 2013. Some file types are safer than others, as some could allow malicious code to become active on user computers or the network. For this reason, disabling or not configuring this setting could allow malicious code to become active on user computers or the network.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Set default file block behavior" to "Enabled: Blocked files are not opened".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Set default file block behavior" is set to "Enabled: Blocked files are not opened". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value OpenInProtectedView is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Open/Save actions for web pages and Excel 2003 XML spreadsheets must be blocked.

Finding ID
DTOO120
Rule ID
SV-53638r2_rule
Severity
Cat III
CCE
(None)
Group Title
DTOO120 -Web pages and Excel 2003 XML spreadsheets
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This policy setting allows for determining whether users can open, view, edit, or save Excel files with the format specified by the title

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Web pages and Excel 2003 XML spreadsheets" to "Enabled: Open/Save blocked, use open policy".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> File Block Settings "Web pages and Excel 2003 XML spreadsheets" is set to "Enabled: Open/Save blocked, use open policy". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\fileblock Criteria: If the value HtmlandXmlssFiles is REG_DWORD = 2, this is not a finding.

Responsibility

System Administrator

Files from the Internet zone must be opened in Protected View.

Finding ID
DTOO121
Rule ID
SV-53676r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO121 - Files from the Internet zone
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This policy setting allows for determining if files downloaded from the Internet zone open in Protected View. If enabling this policy setting, files downloaded from the Internet zone do not open in Protected View. If disabling or not configuring this policy setting, files downloaded from the Internet zone open in Protected View.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Do not open files from the Internet zone in Protected View" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Do not open files from the Internet zone in Protected View" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\protectedview Criteria: If the value DisableInternetFilesInPV is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Files in unsafe locations must be opened in Protected View.

Finding ID
DTOO288
Rule ID
SV-53831r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO288 - Files in unsafe locations
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

This policy setting determines whether files located in unsafe locations will open in Protected View. If unsafe locations have not been specified, only the "Downloaded Program Files" and "Temporary Internet Files" folders are considered unsafe locations. If enabling this policy setting, files located in unsafe locations do not open in Protected View. If disabling or not configuring this policy setting, files located in unsafe locations open in Protected View.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Do not open files in unsafe locations in Protected View" to "Disabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Do not open files in unsafe locations in Protected View" is set to "Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\protectedview Criteria: If the value DisableUnsafeLocationsInPV is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

Document behavior if file validation fails must be set.

Finding ID
DTOO292
Rule ID
SV-53834r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO292 - Set document behavior
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

This policy key controls how Office documents should be handled when failing file validation. By requiring such documents to be opened in Protected View, any potentially malicious code would be disabled, allowing the user to edit the document and resave correctly.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Set document behavior if file validation fails" to "Enabled: Open in Protected View" and Unchecked for "Do not allow edit".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Set document behavior if file validation fails" is set to "Enabled: Open in Protected View" and Unchecked for "Do not allow edit". Procedure: Use the Windows Registry Editor to navigate to the following keys: If both HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\filevalidation\OpenInProtectedView is set to REG_DWORD = 1 and HKCU\Software\Policies\Microsoft\Office\15.0\excel\security\filevalidation\DisableEditFromPV is set to REG_DWORD = 1, this is not a finding. If either, or both keys, is not set to REG_DWORD = 1, this is a finding.

Responsibility

System Administrator

Excel attachments opened from Outlook must be in Protected View.

Finding ID
DTOO293
Rule ID
SV-53837r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO293 - Turn off Protected View for attachments
CCI
CCI-001170
Target Key
(None)
Documentable
No
Discussion

This policy setting allows for determining whether Excel files in Outlook attachments open in Protected View. If enabling this policy setting, Outlook attachments do not open in Protected View. If disabling or not configuring this policy setting, Outlook attachments open in Protected View.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View "Turn off Protected View for attachments opened from Outlook" to "Disabled".

Check Content

The policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> Trust Center -> Protected View Turn off Protected View for attachments opened from Outlook" must be set to Disabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\Software\Policies\Microsoft\Office\15.0\Excel\security\protectedview Criteria: If the value DisableAttachmentsInPV is REG_DWORD = 0, this is not a finding.

Responsibility

System Administrator

WEBSERVICE functions must be disabled.

Finding ID
DTOO418
Rule ID
SV-53841r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO418 - Disable WEBSERVICE functions
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

The WEBSERVICE function option, when used in an Excel spreadsheet, returns data from a web service on the Internet or Intranet. If allowed to be used, security is significantly reduced by allowing information disclosure to third party web services and could potentially introduce malicious content to the local network. The WEBSERVICE function must be disabled in Excel and configured to notify user if a WEBSERVICE function is present in an Excel spreadsheet.

Fix Text

Set policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> " WEBSERVICE Function Notification Settings" is set to "Enabled: Disable all with notifications".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Excel Options -> Security -> " WEBSERVICE Function Notification Settings" is set to "Enabled: Disable all with notifications". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\Microsoft\office\15.0\excel\security Criteria: If the value webservicefunctionwarnings is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator

Corrupt workbook options must be disallowed.

Finding ID
DTOO419
Rule ID
SV-53843r1_rule
Severity
Cat II
CCE
(None)
Group Title
DTOO419 - Disallow corrupt workbook options
CCI
CCI-001662
Target Key
(None)
Documentable
No
Discussion

This setting controls whether Excel presents users with a list of data extraction options before beginning an Open and Repair operation when users choose to open a corrupt workbook in repair or extract mode. A corrupt Excel file may be indicative of malicious tampering. By allowing the automatic handling of corrupt spreadsheets, malicious code may be introduced to the user's computer and the network.

Fix Text

Set the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Data Recovery -> "Do not show data extraction options when opening corrupt workbooks" to "Enabled".

Check Content

Verify the policy value for User Configuration -> Administrative Templates -> Microsoft Excel 2013 -> Data Recovery -> "Do not show data extraction options when opening corrupt workbooks" is set to "Enabled". Procedure: Use the Windows Registry Editor to navigate to the following key: HKCU\software\policies\microsoft\office\15.0\excel\options Criteria: If the value extractdatadisableui is REG_DWORD = 1, this is not a finding.

Responsibility

System Administrator