CVE-2011-1468 in PHP
Summary
by MITRE
Multiple memory leaks in the OpenSSL extension in PHP before 5.3.6 might allow remote attackers to cause a denial of service (memory consumption) via (1) plaintext data to the openssl_encrypt function or (2) ciphertext data to the openssl_decrypt function.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2011-1468 represents a critical memory management flaw within the OpenSSL extension of PHP versions prior to 5.3.6. This issue manifests as multiple memory leaks that occur during cryptographic operations, specifically when handling encryption and decryption functions. The flaw enables remote attackers to exploit the memory allocation mechanisms within PHP's OpenSSL implementation, leading to progressive memory consumption that can ultimately result in system resource exhaustion and denial of service conditions.
The technical implementation of this vulnerability stems from insufficient memory deallocation within the openssl_encrypt and openssl_decrypt functions. When plaintext data is passed to openssl_encrypt or ciphertext data is processed through openssl_decrypt, the underlying OpenSSL library fails to properly release allocated memory blocks. This occurs due to improper error handling and memory management routines within the PHP extension code, where allocated buffers for cryptographic operations are not consistently freed even when operations complete or fail. The memory leaks compound over time as repeated cryptographic operations continue to accumulate unreleased memory segments, creating a gradual degradation of system performance.
From an operational perspective, this vulnerability poses significant risks to web applications and services that rely heavily on PHP's OpenSSL functionality for secure communications, data encryption, and authentication processes. Attackers can exploit this weakness by repeatedly invoking the affected functions with malicious data inputs, causing progressive memory consumption that can lead to service interruption, application crashes, or complete system instability. The remote nature of the attack means that any web application using vulnerable PHP versions is at risk, particularly those handling high volumes of encrypted data or those exposed to untrusted input streams. This vulnerability directly maps to CWE-401 Memory Leak, which is categorized under the weakness identification system for memory management issues.
The impact of this vulnerability extends beyond simple resource exhaustion, as it can be leveraged as part of broader attack strategies within the adversary lifecycle. According to ATT&CK framework, this weakness could be categorized under privilege escalation and denial of service tactics, potentially serving as a stepping stone for more sophisticated attacks. The vulnerability affects the availability aspect of the CIA triad by compromising system stability and resource integrity. Organizations running vulnerable PHP versions may experience cascading failures, as memory exhaustion can affect not only the specific web application but also underlying system processes and other services running on the same infrastructure.
Mitigation strategies for CVE-2011-1468 primarily focus on immediate PHP version upgrades to 5.3.6 or later, which contain the necessary patches to address the memory leak conditions. System administrators should also implement monitoring solutions to detect abnormal memory consumption patterns that could indicate exploitation attempts. Additionally, input validation and sanitization measures should be enhanced to limit the volume and complexity of data processed through cryptographic functions. The vulnerability demonstrates the importance of regular security updates and the potential for seemingly minor memory management issues to create significant operational risks in web application environments. Organizations should also consider implementing rate limiting and resource quotas for cryptographic operations to prevent exploitation even if the underlying vulnerability remains unpatched temporarily.