Microsoft DotNet Framework 4.0 STIG Version Comparison

There are 3 differences between versions v2 r4 (April 24, 2024) (the "left" version) and v2 r6 (April 2, 2025) (the "right" version).

Check APPNET0064 was changed between these two versions. Green, underlined text was added, red, struck-out text was removed.

The regular view of the left check and right check may be easier to read.

Title

.Net applications that invoke NetFx40_LegacySecurityPolicy must apply previous versions of .NET STIG guidance.

Check Content

Open The infrastructure to enable Code Access Security (CAS) exists only in .NET Framework 2.x - 4.x. The requirement is Not Applicable (NA) for .NET Framework > 4.x. (Note: The infrastructure is deprecated and is not receiving servicing or security fixes.) Open Windows explorer and search for all *.exe.config files. This requirement does not apply to the caspol.exe assembly or other assemblies provided with the Windows OS or the Windows Secure Host Baseline (SHB). To find relevant files, you can run the FINDSTR command from an elevated (admin) command prompt: FINDSTR /i /s "NetFx40_LegacySecurityPolicy" c:\*.exe.config This c:\*.exe.config This command will search all ."exe.config" files on the c: drive partition for the "LegacySecurityPolicy" setting. Repeat the command for each drive partition on the system. If system. If the .NET application configuration file utilizes uses the legacy policy element element, and .NET STIG guidance that covers these legacy versions has not been applied, this is a finding.

Discussion

CAS policy is .NET runtime version-specific. In .NET Framework version 4, CAS policy is disabled by default however; it can be re-enabled by using the NetFx40_LegacySecurityPolicy setting on a per application basis. Caspol.exe is provided by Microsoft to set security policy on .Net applications prior to version 4.0. This requirement does not apply to the caspol.exe assembly or other assemblies provided with the Windows OS or the Windows Secure Host Baseline (SHB). When invoking the NetFx40_LegacySecurityPolicy setting in .NET 4, earlier versions of the .NET Framework CAS policy will become active therefore previous .NET STIG guidance that applies to the reactivated versions must also be applied. Failure to apply applicable versions of STIG guidance can result in the loss of system confidentiality, integrity or availability.

Fix

Apply The infrastructure to enable CAS exists only in .NET Framework 2.x - 4.x. The requirement is Not Applicable (NA) for .NET Framework > 4.x. (Note: The infrastructure is deprecated and is not receiving servicing or security fixes.) Apply the .NET Framework Security Checklist for .Net versions 1 through 3.5 when utilizing using the NetFx40_LegacySecurityPolicy setting.