1.2.1.11 Ensure 'Consistent Mime Handling' is set to Enabled - visio.exe

Information

Internet Explorer uses Multipurpose Internet Mail Extensions (MIME) data to determine file handling procedures for files received through a Web server. This policy setting determines whether Internet Explorer requires that all file-type information provided by Web servers be consistent. For example, if the MIME type of a file is text/plain but the MIME data indicates that the file is really an executable file, Internet Explorer changes its extension to reflect this executable status. This capability helps ensure that executable code cannot masquerade as other types of data that may be trusted. The recommended state for this setting is: Enabled.(Check: groove.exe, excel.exe, mspub.exe, powerpnt.exe, pptview.exe, visio.exe, winproj.exe, outlook.exe, spDesign.exe, exprwd.exe, msaccess.exe, onent.exe, mse7.exe) Users can use Internet Explorer to unknowingly download malicious content disguised with an incorrect filename extension or incorrectly marked in the MIME header. Once downloaded, an incorrect handler can run the file, enabling the malicious content to cause damage to the users system or network.

Solution

To implement the recommended configuration state, set the following Group Policy setting to Enabled. Computer Configuration\Administrative Templates\Microsoft Office 2016 (Machine)\Security Settings\IE Security\Consistent Mime Handling Impact: Internet Explorer use both the extension of the filename and the MIME information to decide how to handle a file. Enabling this setting requires that information in the MIME header matches the file extension provided. Since mismatched files will be blocked by enabling this setting, you should insure that any web server under your control is set up correctly.

See Also

https://workbench.cisecurity.org/files/571

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CSCv6|3.1

Plugin: Windows

Control ID: cb38f7f97806d2853aee1bda5862f923f0d5cc036e038738c17e7aaf585aba92