CVE-2012-6113 in PHP
Summary
by MITRE
The openssl_encrypt function in ext/openssl/openssl.c in PHP 5.3.9 through 5.3.13 does not initialize a certain variable, which allows remote attackers to obtain sensitive information from process memory by providing zero bytes of input data.
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Analysis
by VulDB Data Team • 12/21/2021
The vulnerability identified as CVE-2012-6113 represents a critical information disclosure flaw within the PHP OpenSSL extension that affects versions 5.3.9 through 5.3.13. This vulnerability resides in the openssl_encrypt function located within the ext/openssl/openssl.c source file, where a variable fails to be properly initialized during the encryption process. The flaw stems from inadequate memory management practices that leave sensitive data remnants in memory locations, creating potential exposure pathways for attackers seeking to extract confidential information from system processes.
The technical nature of this vulnerability aligns with CWE-1288, which specifically addresses uninitialized variables in cryptographic functions, making it a direct descendant of improper initialization flaws that can lead to information leakage. When the openssl_encrypt function receives zero bytes of input data, the uninitialized variable retains its previous memory contents, which may contain sensitive information from prior operations or system processes. This behavior creates a scenario where remote attackers can exploit the function to perform memory probing attacks and extract potentially valuable data such as cryptographic keys, session tokens, or other confidential information that may have resided in the same memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to perform more sophisticated attacks including credential harvesting, session hijacking, and cryptographic key recovery. The vulnerability is particularly dangerous because it requires minimal input to exploit, making it accessible to attackers with basic knowledge of the PHP environment. The remote nature of the attack means that adversaries can leverage this flaw from outside the system boundary, potentially compromising web applications that utilize the affected PHP versions for encryption operations. This vulnerability directly maps to attack techniques described in the ATT&CK framework under T1552.001 for Unsecured Credentials and T1005 for Data from Local System, as it allows unauthorized access to sensitive data that should remain protected.
Mitigation strategies for CVE-2012-6113 primarily focus on immediate version upgrades to PHP 5.3.14 or later, which contain the necessary patches to properly initialize the affected variable. Organizations should also implement network segmentation and access controls to limit exposure of vulnerable systems, while monitoring for potential exploitation attempts through intrusion detection systems. Additionally, developers should avoid using the vulnerable openssl_encrypt function with untrusted input data and consider implementing additional input validation measures to prevent exploitation. The vulnerability demonstrates the critical importance of proper memory initialization in cryptographic operations, as highlighted in industry best practices for secure coding standards that emphasize the need for comprehensive variable initialization and memory management to prevent information leakage vulnerabilities.