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


Finding ID Version Rule ID IA Controls Severity
V-92687 AS24-U1-000510 SV-102775r1_rule Medium
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.
Apache Server 2.4 UNIX Server Security Technical Implementation Guide 2020-06-17


Check Text ( C-91991r1_chk )
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:

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

Review the "httpd.conf" file.

If the "SessionCryptoCipher" is not used or "SessionCryptoCipher" is not set to "aes256", this is a finding.
Fix Text (F-98929r1_fix)
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