CVE-2010-2191 in PHP
Summary
by MITRE
The (1) parse_str, (2) preg_match, (3) unpack, and (4) pack functions; the (5) ZEND_FETCH_RW, (6) ZEND_CONCAT, and (7) ZEND_ASSIGN_CONCAT opcodes; and the (8) ArrayObject::uasort method in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allow context-dependent attackers to obtain sensitive information (memory contents) or trigger memory corruption by causing a userspace interruption of an internal function or handler. NOTE: vectors 2 through 4 are related to the call time pass by reference feature.
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Analysis
by VulDB Data Team • 02/01/2025
The vulnerability described in CVE-2010-2191 represents a critical security flaw affecting multiple core PHP functions and opcodes that enable context-dependent attackers to extract sensitive memory contents or cause memory corruption. This vulnerability impacts PHP versions 5.2 through 5.2.13 and 5.3 through 5.3.2, making it a widespread concern for web applications built on these platforms. The issue stems from improper handling of internal function interruptions during userspace operations, creating potential attack vectors that can be exploited to compromise system security.
The technical flaw manifests through several PHP internal mechanisms including parse_str, preg_match, unpack, and pack functions which are commonly used for data processing and manipulation. Additionally, the ZEND_FETCH_RW, ZEND_CONCAT, and ZEND_ASSIGN_CONCAT opcodes, which are fundamental to PHP's bytecode execution, are also affected. The ArrayObject::uasort method further compounds the vulnerability by allowing attackers to manipulate array sorting operations in ways that can trigger memory access issues. These functions and opcodes all share a common weakness in their handling of userspace interruptions during internal function execution, creating opportunities for memory disclosure and corruption.
The operational impact of this vulnerability is significant as it allows attackers to potentially access sensitive information stored in memory, including passwords, session tokens, and other confidential data that may be present in the application's memory space. The memory corruption aspect presents even more severe risks, as it can lead to application crashes, denial of service conditions, or potentially enable more sophisticated attacks such as code execution. The vulnerability's context-dependent nature means that exploitation requires specific conditions to be met, but once achieved, the consequences can be devastating for affected systems. This vulnerability directly relates to CWE-125, which describes out-of-bounds read conditions, and CWE-122, which covers buffer overflow conditions, both of which are fundamental memory safety issues.
Attackers can leverage this vulnerability through the call time pass by reference feature, which was a deprecated but still functional aspect of PHP's design. The exploitation process typically involves manipulating input data to cause specific internal function interruptions that result in memory access patterns revealing sensitive information. This vulnerability aligns with ATT&CK technique T1059, which involves execution through command and scripting interpreters, as attackers may use PHP's vulnerable functions to gain unauthorized access to system memory. The memory disclosure aspect can also map to ATT&CK technique T1005, which involves data from local system, as attackers can extract sensitive information from memory locations where such data is stored.
Mitigation strategies for CVE-2010-2191 primarily involve upgrading to patched versions of PHP where the vulnerability has been addressed through proper handling of internal function interruptions. System administrators should also implement input validation measures to prevent malicious data from reaching vulnerable functions, though this approach provides only partial protection. Additionally, monitoring for unusual memory access patterns and implementing proper error handling can help detect potential exploitation attempts. The vulnerability underscores the importance of keeping PHP installations updated and highlights the critical need for proper memory management in interpreted languages. Organizations should also consider implementing application firewalls and intrusion detection systems to monitor for exploitation attempts targeting these specific functions and opcodes.