CVE-2006-3204 in Ultimate PHP Board
Summary
by MITRE
Ultimate PHP Board (UPB) 1.9.6 and earlier uses a cryptographically weak block cipher with a large key collision space, which allows remote attackers to determine a suitable decryption key given the plaintext and ciphertext by obtaining the plaintext password, which is sent when logging in, and the ciphertext, which is set in the pass_env cookie.
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Analysis
by VulDB Data Team • 09/17/2017
The vulnerability described in CVE-2006-3204 affects Ultimate PHP Board version 1.9.6 and earlier, representing a critical cryptographic weakness that compromises user authentication security. This issue stems from the application's implementation of a cryptographically weak block cipher algorithm that suffers from significant mathematical flaws in its design. The weakness becomes particularly dangerous because it enables attackers to perform key recovery attacks when both plaintext and ciphertext are available, creating a scenario where authentication credentials can be directly compromised through cryptanalysis rather than traditional brute force methods.
The technical flaw manifests in the application's handling of user authentication tokens through the pass_env cookie mechanism. When users log in, the system sends the plaintext password over the network, while simultaneously storing the corresponding ciphertext in the pass_env cookie. This dual exposure creates an ideal environment for chosen plaintext attacks, where an attacker can capture both the original password and its encrypted form. The specific cipher implementation contains a large key collision space, meaning that multiple keys can produce identical ciphertext outputs for given plaintext inputs, making the decryption process susceptible to mathematical analysis and pattern recognition techniques.
From an operational impact perspective, this vulnerability allows remote attackers to completely bypass authentication mechanisms and gain unauthorized access to user accounts. The attack requires minimal resources and can be executed by anyone who can intercept network traffic or gain access to the pass_env cookie, making it particularly dangerous for web applications handling sensitive user data. The vulnerability affects the entire user base of affected UPB installations, potentially enabling attackers to access personal information, private communications, and other sensitive data stored within the board system. This weakness essentially transforms the authentication system from a security control into a vulnerability that directly exposes user credentials and session information.
Security professionals should note that this vulnerability aligns with several common attack patterns documented in the attack framework, particularly those involving cryptographic weaknesses and credential compromise. The issue relates to CWE-327, which addresses the use of weak cryptographic algorithms, and CWE-310, covering cryptographic issues in authentication mechanisms. Mitigation strategies should include immediate implementation of strong encryption algorithms such as AES or RSA with appropriate key lengths, proper session management protocols, and removal of any weak cryptographic implementations. Organizations should also implement network monitoring to detect suspicious traffic patterns and ensure that authentication tokens are not transmitted in predictable formats. The most effective long-term solution involves upgrading to a supported version of UPB that employs modern cryptographic standards and implementing proper security controls to prevent similar vulnerabilities in future development cycles.