CVE-2011-3268 in PHP
Summary
by MITRE
Buffer overflow in the crypt function in PHP before 5.3.7 allows context-dependent attackers to have an unspecified impact via a long salt argument, a different vulnerability than CVE-2011-2483.
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Analysis
by VulDB Data Team • 01/06/2025
The vulnerability identified as CVE-2011-3268 represents a critical buffer overflow flaw within PHP's crypt function implementation, affecting versions prior to 5.3.7. This vulnerability specifically manifests when processing excessively long salt arguments, creating a condition where memory boundaries are exceeded during cryptographic hash generation operations. The flaw operates at the core level of PHP's password hashing mechanism, making it particularly dangerous as it can be exploited by attackers who control input parameters passed to the crypt function. The vulnerability is classified as context-dependent, meaning its exploitation requires specific conditions or attacker-controlled inputs that trigger the problematic code path within the cryptographic library.
The technical implementation of this buffer overflow stems from inadequate input validation and boundary checking within the crypt function's internal handling of salt parameters. When a salt argument exceeds predetermined memory limits, the function fails to properly manage memory allocation and copying operations, leading to memory corruption that can result in arbitrary code execution or application crashes. This vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and specifically relates to improper input validation of cryptographic parameters. The flaw demonstrates a classic weakness in memory management where the system does not adequately check the length of user-supplied salt values before processing them through the cryptographic hashing algorithms.
From an operational perspective, this vulnerability poses significant risks to web applications that rely on PHP's crypt function for password hashing and authentication purposes. Attackers could potentially exploit this flaw by supplying maliciously crafted salt values that trigger the buffer overflow condition, leading to system compromise or denial of service attacks. The impact extends beyond simple application crashes to include potential privilege escalation and unauthorized access to sensitive systems. This vulnerability is particularly concerning in environments where PHP applications handle user authentication, as it could allow attackers to bypass authentication mechanisms or gain elevated system privileges. The exploitation requires minimal privileges and can be automated, making it a high-value target for malicious actors in both targeted and opportunistic attacks.
Mitigation strategies for CVE-2011-3268 primarily focus on immediate version upgrades to PHP 5.3.7 or later, which contain patches addressing the buffer overflow condition. Organizations should also implement input validation measures that enforce reasonable limits on salt parameter lengths before passing them to the crypt function. Additionally, security monitoring should be enhanced to detect unusual patterns in authentication attempts that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1110.003, which covers credential dumping through password hash recovery, and represents a critical weakness that should be prioritized for remediation in security assessment programs. Regular security audits and vulnerability scanning should include checks for outdated PHP installations to prevent exploitation of this and similar historical vulnerabilities.