The web server must generate a session ID using as much of the character set as possible to reduce the risk of brute force.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-41809	SRG-APP-000224-WSR-000138	SV-54386r3_rule		Medium

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. By generating session IDs that contain as much of the character set as possible, i.e., A-Z, a-z, and 0-9, the session ID becomes exponentially harder to guess.

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. By generating session IDs that contain as much of the character set as possible, i.e., A-Z, a-z, and 0-9, the session ID becomes exponentially harder to guess.

STIG	Date
Web Server Security Requirements Guide	2019-03-20

Details

Check Text ( C-48197r2_chk )
Review the web server documentation and deployed configuration to determine what characters are used in generating session IDs. If the web server is not configured to use at least A-Z, a-z, and 0-9 to generate session identifiers, this is a finding.

Fix Text (F-47268r2_fix)
Configure the web server to use at least A-Z, a-z, and 0-9 to generate session IDs.