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

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-214252	SRG-APP-000224-WSR-000137	AS24-U1-000510	SV-214252r1043181_rule	2024-12-04	3

Description
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.

Description

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.

ℹ️ Check
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.

ℹ️ Check

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.

✔️ 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