CVE-2008-6792 in Linux
Summary
by MITRE
system-tools-backends before 2.6.0-1ubuntu1.1 in Ubuntu 8.10, as used by "Users and Groups" in GNOME System Tools, hashes account passwords with 3DES and consequently limits effective password lengths to eight characters, which makes it easier for context-dependent attackers to successfully conduct brute-force password attacks.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/21/2019
The vulnerability identified as CVE-2008-6792 affects the system-tools-backends package version prior to 2.6.0-1ubuntu1.1 in Ubuntu 8.10, specifically within the GNOME System Tools "Users and Groups" component. This flaw stems from the implementation of password hashing mechanisms that utilize the 3DES encryption algorithm, creating a fundamental security weakness that directly impacts password strength and authentication security. The vulnerability resides in how the system processes and stores user account passwords through an outdated cryptographic approach that fails to properly handle password lengths exceeding eight characters.
The technical implementation of this vulnerability demonstrates a classic cryptographic weakness where the 3DES hashing algorithm truncates passwords to eight characters before processing, effectively limiting the entropy of password hashes. This truncation occurs during the password hashing process, where the system takes the original password input and applies the 3DES algorithm to only the first eight characters, completely ignoring any additional characters beyond that limit. This design flaw creates a significant reduction in the search space for potential password cracking attempts, as attackers only need to brute-force the first eight characters of the password rather than the full password length.
From an operational perspective, this vulnerability creates an exploitable condition that significantly weakens password security for user accounts managed through the GNOME System Tools interface. The impact extends beyond simple password cracking as it fundamentally undermines the security model of the authentication system, making it considerably easier for context-dependent attackers to successfully compromise user accounts. Attackers can leverage this weakness to conduct more efficient brute-force attacks, as the effective password length is reduced from potentially many characters to just eight characters, dramatically decreasing the computational effort required to discover valid passwords.
The vulnerability aligns with CWE-326, which addresses the weakness of using weak encryption algorithms for password storage, and demonstrates characteristics consistent with CWE-327, relating to the use of insecure cryptographic algorithms. From an attacker's perspective, this vulnerability maps to ATT&CK technique T1110.001, which involves the use of brute force methods for password guessing, and T1110.003, which covers password cracking techniques. The reduced password entropy makes the system more susceptible to dictionary attacks and rainbow table generation, as the limited character set significantly decreases the complexity of potential password combinations that need to be tested.
The mitigation strategy for this vulnerability requires immediate patching of the system-tools-backends package to version 2.6.0-1ubuntu1.1 or later, which implements proper password hashing mechanisms that do not truncate passwords to eight characters. System administrators should also consider implementing additional security controls such as account lockout policies, multi-factor authentication, and regular password audits to compensate for the reduced security posture. Organizations should conduct vulnerability assessments to identify all systems running affected versions and ensure comprehensive patch management procedures are in place to prevent similar cryptographic weaknesses in other system components.