Title

The KeepAlive directive must be enabled. (Cat II impact)

Discussion

The KeepAlive extension to HTTP/1.0 and the persistent connection feature of HTTP/1.1 provide long lived HTTP sessions which allow multiple requests to be sent over the same connection. These requirements are set to mitigate the effects of several types of denial of service attacks. Although there is some latitude concerning the settings themselves, the requirements attempt to provide reasonable limits for the protection of the web server. If necessary, these limits can be adjusted to accommodate the operational requirement of a given system.

Check Content

Locate the Apache httpd.conf file. Open the httpd.conf file with an editor such as notepad, and search for the following uncommented directive: KeepAlive Every enabled KeepAlive value needs to be set to “On”. If any directive is set improperly, this is a finding. If any directive is set to “Off”, this is a finding. NOTE: This vulnerability can be documented locally with the ISSM/ISSO if the site has an operational reason for not using persistent connections. If the site has this documented, this should be marked as Not a Finding.

Fix Text

Modify the KeepAlive directive in the applicable Apache configuration files to have a value of On.

Additional Identifiers

Rule ID: SV-32987r2_rule

Vulnerability ID: V-13725

Group Title: WA000-WWA022

Expert Comments

CCIs tied to check.

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