AS24-U2-000630 - Warning and error messages displayed to clients must be modified to minimize the identity of the Apache web server, patches, loaded modules, and directory paths.

Information

Information needed by an attacker to begin looking for possible vulnerabilities in an Apache web server includes any information about the Apache web server, backend systems being accessed, and plug-ins or modules being used.

Apache web servers will often display error messages to client users, displaying enough information to aid in the debugging of the error. The information given back in error messages may display the Apache web server type, version, patches installed, plug-ins and modules installed, type of code being used by the hosted application, and any backends being used for data storage.

This information could be used by an attacker to blueprint what type of attacks might be successful. The information given to users must be minimized to not aid in the blueprinting of the Apache web server.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Determine the location of the 'HTTPD_ROOT' directory and the 'httpd.conf' file:

# httpd -V | egrep -i 'httpd_root|server_config_file'
-D HTTPD_ROOT='/etc/httpd'
-D SERVER_CONFIG_FILE='conf/httpd.conf'

Use the 'ErrorDocument' directive to enable custom error pages.

ErrorDocument 500 'Sorry, our script crashed. Oh dear'
ErrorDocument 500 /cgi-bin/crash-recover
ErrorDocument 500 http://error.example.com/server_error.html
ErrorDocument 404 /errors/not_found.html
ErrorDocument 401 /subscription/how_to_subscribe.html

The syntax of the ErrorDocument directive is:

ErrorDocument <3-digit-code> <action>

Additional Information:

https://httpd.apache.org/docs/2.4/custom-error.html

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Apache_Server_2-4_UNIX_Y22M01_STIG.zip

Item Details

Category: SYSTEM AND INFORMATION INTEGRITY

References: 800-53|SI-11a., CAT|II, CCI|CCI-001312, Rule-ID|SV-214293r612241_rule, STIG-ID|AS24-U2-000630, STIG-Legacy|SV-102893, STIG-Legacy|V-92805, Vuln-ID|V-214293

Plugin: Unix

Control ID: 69bef8a6f9e952c9fe5129a27d1af88ebb67ffab154cf282c507e74bb725dd72