Title

The UrlSegmentMaxLength registry entry must be set properly. (Cat II impact)

Discussion

Http.sys is the kernel mode driver that handles HTTP requests. There are several registry keys associated with http.sys. The UrlSegmentMaxLength key sets the maximum number of characters in a URL path segment (the area between the slashes in the URL). Setting this value too large may cause performance or a Denial of Service condition on the web server.

Check Content

1. Open the registry editor. 2. Navigate to the following location in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters. 3. Ensure the value for the UrlSegmentMaxLength key is set to REG_DWORD 260 (or less). If the registry key is not set to 260 (or less) or is missing, this is a finding.

Fix Text

1. Open the registry editor. 2. Navigate to the following location in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters. 3. Set the value for the UrlSegmentMaxLength key to REG_DWORD 260 (or less) or add the key and set it to REG_DWORD 260.

Additional Identifiers

Rule ID: SV-38165r1_rule

Vulnerability ID: V-13719

Group Title:

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.