Non-ASCII characters in URLs must be prohibited by any IIS 8.5 website.

From IIS 8.5 Site Security Technical Implementation Guide

Associated with: CCI-001094

SV-91519r1_rule Non-ASCII characters in URLs must be prohibited by any IIS 8.5 website.

Vulnerability discussion

By setting limits on web requests, it 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.

Check content

Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 Manager. Click on 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 text

Follow the procedures below for each site hosted on the IIS 8.5 web server: Open the IIS 8.5 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.

Pro Tips

Lavender hyperlinks in small type off to the right (of CSS class id, if you view the page source) point to globally unique URIs for each document and item. Copy the link location and paste anywhere you need to talk unambiguously about these things.

You can obtain data about documents and items in other formats. Simply provide an HTTP header Accept: text/turtle or Accept: application/rdf+xml.