Unspecified file extensions on a production IIS 10.0 web server must be removed.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-218824 | IIST-SV-000158 | SV-218824r961863_rule | CCI-000366 | medium |
| Description | ||||
| 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. | ||||
| STIG | Date | |||
| Microsoft IIS 10.0 Server Security Technical Implementation Guide | 2025-06-11 | |||
Related Frameworks
4 paths across 3 frameworks
Related Frameworks
NIST 800-531 mapping
CM-6
1.00
- DISA · 3 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
NIST 800-1712 mappings
3.4.1
1.00
- DISA · 3 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
- NIST · Rev 2 (Feb 2020, errata Jan 2021) · nist_800_171_app_d · equivalent
3.4.2
1.00
- DISA · 3 · disa_xccdf · related
- DISA · 2025-01-23 · disa_cci_list · equivalent
- NIST · Rev 2 (Feb 2020, errata Jan 2021) · nist_800_171_app_d · equivalent
CCI1 mapping
CCI-000366
1.00
- DISA · 3 · disa_xccdf · related
Details
Check Text (C-218824r961863_chk)
Open the IIS 10.0 Manager.
Click the IIS 10.0 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.
Fix Text (F-20294r310948_fix)
Open the IIS 10.0 Manager.
Click the IIS 10.0 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".