7.7 Ensure SSL Compression is not Enabled

Information

The SSLCompression directive controls whether SSL compression is used by Apache when serving content over HTTPS. It is recommended that the SSLCompression directive be set to off.

Rationale:

If SSL compression is enabled, HTTPS communication between the client and the server may be at increased risk to the CRIME attack. The CRIME attack increases a malicious actor's ability to derive the value of a session cookie, which commonly contains an authenticator. If the authenticator in a session cookie is derived, it can be used to impersonate the account associated with the authenticator.

Solution

Perform the following to implement the recommended state:

Search the Apache configuration files for the SSLCompression directive.

If the directive is present, set it to off.

Default Value:

In Apache versions >= 2.4.3, the SSLCompression directive is available and SSL compression is implicitly disabled. In Apache 2.4 - 2.4.2, the SSLCompression directive is not available and SSL compression is implicitly disabled.

See Also

https://workbench.cisecurity.org/files/3021