Non-ASCII characters in URLs must be prohibited by any IIS 10.0 website.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-218756 | SRG-APP-000246-WSR-000149 | IIST-SI-000228 | SV-218756r1210388_rule | 2026-05-23 | 2 |
Description
Setting limits on web requests ensures availability of web services and mitigates the risk of buffer overflow type attacks. The allow high-bit characters Request Filter enables rejection of requests containing non-ASCII characters.
ℹ️ Check
Note: If either of the following is true, this requirement is Not Applicable:
- The server being reviewed is hosting SharePoint.
- This IIS 10.0 installation is supporting Microsoft Exchange and not otherwise hosting any content.
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.
Double-click the "Request Filtering" icon.
Click "Edit Feature Settings" in the "Actions" pane.
If the "Allow high-bit characters" check box is checked, this is a finding.
✔️ Fix
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 under review.
Double-click the "Request Filtering" icon.
Click "Edit Feature Settings" in the "Actions" pane.
Uncheck the "Allow high-bit characters" check box.