CVE-2006-0632 in phpBB
Summary
by MITRE
The gen_rand_string function in phpBB 2.0.19 uses insufficiently random data (small value space) to create the activation key ("validation ID") that is sent by e-mail when establishing a password, which makes it easier for remote attackers to obtain the key and modify passwords for existing accounts or create new accounts.
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Analysis
by VulDB Data Team • 07/18/2018
The vulnerability described in CVE-2006-0632 represents a critical weakness in the phpBB 2.0.19 forum software's password reset mechanism. This issue specifically targets the gen_rand_string function which is responsible for generating activation keys or validation IDs used during the password recovery process. The flaw lies in the insufficient randomness of the generated values, creating a predictable and exploitable pattern that compromises the security of user account management. The vulnerability directly impacts the authentication and authorization mechanisms of the forum system, making it susceptible to unauthorized account access and manipulation.
The technical implementation of this vulnerability stems from the inadequate entropy in the random number generation process within the gen_rand_string function. When phpBB generates activation keys for password recovery, it utilizes a limited value space that significantly reduces the cryptographic strength of these identifiers. This weakness creates a mathematical vulnerability where attackers can potentially enumerate or guess valid activation keys through brute force or statistical analysis techniques. The small value space essentially transforms what should be cryptographically secure random values into predictable sequences that can be exploited by remote attackers. This flaw aligns with CWE-330, which addresses the use of insufficiently random values in security-critical contexts, and represents a clear violation of proper cryptographic practices in web application security.
The operational impact of this vulnerability extends beyond simple password compromise, as it enables attackers to perform account takeover operations and potentially create new user accounts within the forum system. Remote attackers can exploit this weakness to gain unauthorized access to existing user accounts, modify account settings, or even establish new accounts with elevated privileges. The vulnerability specifically affects the password reset functionality, which is a critical component of user account management and security. This creates a significant risk for forum administrators and users alike, as compromised accounts can lead to data breaches, content manipulation, and potential further exploitation of the compromised system. The attack vector is particularly dangerous because it requires no local access or specialized tools beyond basic network reconnaissance and attack capabilities.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and patches provided by the phpBB development team. Organizations should prioritize upgrading to phpBB versions that address this specific random number generation flaw and implement proper cryptographic random number generation libraries. The solution involves replacing the existing gen_rand_string function with a cryptographically secure random number generator that provides sufficient entropy and prevents predictable value sequences. Security practices should also include monitoring for suspicious account activity and implementing additional authentication layers such as CAPTCHA mechanisms or rate limiting for password reset requests. This vulnerability demonstrates the critical importance of proper random number generation in security-sensitive applications and reinforces the need for adherence to established security standards and best practices in web application development. Organizations should also consider implementing additional security controls such as account lockout mechanisms and enhanced logging to detect and respond to potential exploitation attempts.