Details

IIS 10.0 will either allow or deny script execution based on file extension. The ability to control script execution is controlled through two features with IIS 10.0, Request Filtering and Handler Mappings.

For Request Filtering, the ISSO must document and approve all allowable file extensions the website allows (white list) and denies (black list) by the website. The white list and black list will be compared to the Request Filtering in IIS 10.0. Request Filtering at the site level take precedence over Request Filtering at the server level.

NOTE: Nessus has not performed this check. Please review the benchmark to ensure target compliance.

Solution

Follow the procedures below for each site hosted on the IIS 10.0 web server:

Open the IIS 10.0 Manager.

Click the site name to review.

Double-click Request Filtering->File Name Extensions Tab->Deny File Name Extension.

Add any script file extensions listed on the black list that are not listed.

Select ‘Apply’ from the ‘Actions’ pane.

Supportive Information

The following resource is also helpful.

• https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_MS_IIS_10-0_Y20M10_STIG.zip

This security hardening control applies to the following category of controls within NIST 800-53: Configuration Management.This control applies to the following type of system Windows.

References

• 800-53|CM-7a.
• CAT|II
• CCI|CCI-000381
• Rule-ID|SV-218745r558649_rule
• STIG-ID|IIST-SI-000216
• STIG-Legacy|SV-109315
• STIG-Legacy|V-100211
• Vuln-ID|V-218745

Source

• Tenable.com/audits