Title

The IIS 10.0 website must have resource mappings set to disable the serving of certain file types. (Cat II impact)

Discussion

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.

Check Content

Note: If the server being reviewed is hosting SharePoint, this is Not Applicable. For Request Filtering, the ISSO must document and approve all allowable scripts the website allows (white list) and denies (black list). 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. 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. If any script file extensions from the black list are not denied, this is a finding.

Fix Text

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.

Additional Identifiers

Rule ID: SV-218745r960963_rule

Vulnerability ID: V-218745

Group Title: SRG-APP-000141-WSR-000083

Expert Comments

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