CVE-2008-4102 in Joomla
Summary
by MITRE
Joomla! 1.5 before 1.5.7 initializes PHP s PRNG with a weak seed, which makes it easier for attackers to guess the pseudo-random values produced by PHP s mt_rand function, as demonstrated by guessing password reset tokens, a different vulnerability than CVE-2008-3681.
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Analysis
by VulDB Data Team • 04/21/2019
The vulnerability described in CVE-2008-4102 represents a critical weakness in the Joomla framework, creating a pathway for attackers to exploit predictable sequences.
The technical implementation of this vulnerability occurs at the PHP level where the mt_rand function is seeded with insufficient entropy, typically using predictable values such as the current timestamp or process ID. This weak seeding process results in a predictable sequence of random numbers that can be reverse-engineered by attackers with sufficient computational resources and knowledge of the system's timing characteristics. The vulnerability specifically impacts password reset token generation, which relies on the mt_rand function to produce unpredictable values that should prevent unauthorized access to user accounts. Attackers can leverage this predictability to guess valid reset tokens and gain unauthorized access to user accounts, making this a direct threat to authentication security.
From an operational perspective, this vulnerability creates a significant risk for Joomla! installations running version 1.5.6 or earlier, as it allows attackers to bypass authentication mechanisms and potentially compromise user accounts across the entire platform. The impact extends beyond simple account takeover scenarios since the predictable random number generation affects various security features that depend on cryptographic randomness, including session management, CSRF tokens, and other security mechanisms. This vulnerability operates under the broader category of weak random number generation, which is classified as CWE-330, and represents a specific instance of the more general problem of insufficient entropy in cryptographic implementations. The vulnerability's exploitation is facilitated by the fact that attackers can observe or predict the timing of token generation, making the attack surface more accessible than would be the case with properly seeded random number generators.
The security implications of this vulnerability align with ATT&CK technique T1110.003, which describes credential stuffing and password spraying attacks that can be enhanced by predictable token generation. Organizations using affected Joomla 1.5.7 or later versions where the random number generation has been properly addressed, implementing additional security measures such as rate limiting on password reset requests, and ensuring that all cryptographic functions utilize proper entropy sources. Additionally, system administrators should consider implementing monitoring for unusual authentication patterns and regularly review security configurations to prevent exploitation of similar weaknesses in other components of their web infrastructure.