WA000-WI6092 IIS6 - The PercentUAllowed registry entry must be set properly.

Information

Http.sys is the kernel mode driver that handles HTTP requests. There are several registry keys associated with http.sys. The PercentUAllowed key allows the web server to accept Unicode character syntax via ASCII (i.e., through the URL). Allowing this type of notation, opens the web server to encoding attacks.

Solution

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 PercentUAllowed key to REG_DWORD 0 or add the key and set it to REG_DWORD 0.

See Also

http://iasecontent.disa.mil/stigs/zip/July2015/U_IIS_6-0_V6R16_STIG.zip

Item Details

Category: SYSTEM AND INFORMATION INTEGRITY

References: 800-53|SI-10, CAT|II, Rule-ID|SV-38166r1_rule, STIG-ID|WA000-WI6092_IIS6, Vuln-ID|V-13720

Plugin: Windows

Control ID: b7c0d4cf39ff44fe5d85b0daef687160e461c3f323f2bade8460139a2c9717f8