The Apache web server must generate a session ID long enough that it cannot be guessed through brute force.

Generating a session identifier (ID) that is not easily guessed through brute force is essential to deter several types of session attacks. By knowing the session ID, an attacker can hijack a user session that has already been user authenticated by the hosted application. The attacker does not need to guess user identifiers and passwords or have a secure token since the user session has already been authenticated.

Generating session IDs that are at least 128 bits (16 bytes) in length will cause an attacker to take a large amount of time and resources to guess, reducing the likelihood of an attacker guessing a session ID.

Review the web server documentation and deployed configuration to determine the length of the generated session identifiers.

First ensure that "session_crypto" is enabled:

httpd -M |grep session_crypto

If the above command returns "session_crypto_module", the module is enabled in the running server.

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

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

Note: The apachectl front end is the preferred method for locating the Apache httpd file. For some Linux distributions, "apache2ctl -V" or "httpd -V" can also be used.

Review the "httpd.conf" file.

If the "SessionCryptoCipher" is not used or "SessionCryptoCipher" is not set to "aes256", this is a finding.

Configure the web server to generate session identifiers that are at least 128 bits in length.

Ensure that "session_crypto_module" is enabled.

Determine the location of the "httpd.conf" file by running the following command:

httpd -V

Review the "HTTPD_ROOT" path.

Navigate to the "HTTPD_ROOT"/conf directory.

Edit the "httpd.conf" file.

SessionCryptoCipher aes256

Restart Apache: apachectl restart