CVE-2011-2483 in PHP
Summary
by MITRE
crypt_blowfish before 1.1, as used in PHP before 5.3.7 on certain platforms, PostgreSQL before 8.4.9, and other products, does not properly handle 8-bit characters, which makes it easier for context-dependent attackers to determine a cleartext password by leveraging knowledge of a password hash.
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Analysis
by VulDB Data Team • 11/18/2021
The vulnerability identified as CVE-2011-2483 represents a critical weakness in cryptographic hash functions that affects multiple software platforms including PHP, PostgreSQL, and various other applications utilizing the crypt_blowfish library. This flaw stems from improper handling of 8-bit characters during password hashing operations, creating a significant security risk that can be exploited by context-dependent attackers to reverse-engineer cleartext passwords from their hashed counterparts.
The technical root cause of this vulnerability lies in the crypt_blowfish implementation's failure to properly sanitize or process 8-bit character inputs during the hashing process. When 8-bit characters are present in passwords, the algorithm produces predictable hash outputs that can be systematically analyzed and reverse-engineered through statistical methods and pattern recognition. This weakness specifically impacts the bcrypt hashing algorithm's handling of character encoding, where the implementation does not adequately account for the full range of possible byte values that can occur in 8-bit character sets, leading to deterministic behavior that compromises password security.
The operational impact of this vulnerability extends across multiple software ecosystems where crypt_blowfish is implemented as the primary password hashing mechanism. Systems running affected versions of PHP prior to 5.3.7, PostgreSQL versions before 8.4.9, and other applications relying on this library face significant risk of credential compromise. Attackers with access to password hash databases can leverage this vulnerability to perform password recovery attacks, potentially gaining unauthorized access to user accounts, system resources, and sensitive data repositories. The context-dependent nature of this attack means that successful exploitation requires attackers to have access to both the hash values and knowledge of the target password structure, but the vulnerability significantly reduces the computational complexity required for password recovery.
Security professionals should implement immediate mitigation strategies including updating all affected software components to versions that properly handle 8-bit characters in password hashing operations. The recommended approach involves upgrading to PHP 5.3.7 or later, PostgreSQL 8.4.9 or later, and ensuring all applications utilizing crypt_blowfish have been patched to properly process character encoding. Additionally, organizations should consider implementing additional security controls such as account lockout mechanisms, multi-factor authentication, and regular security audits to reduce the attack surface. From a compliance perspective, this vulnerability aligns with CWE-120, which addresses buffer overflow conditions, and maps to ATT&CK technique T1110.003 for credential access through password recovery methods, highlighting the need for comprehensive security measures beyond simple patching. Organizations should also conduct thorough vulnerability assessments to identify all systems using affected versions of crypt_blowfish and implement monitoring solutions to detect potential exploitation attempts.