CVE-2010-4697 in PHP
Summary
by MITRE
Use-after-free vulnerability in the Zend engine in PHP before 5.2.15 and 5.3.x before 5.3.4 might allow context-dependent attackers to cause a denial of service (heap memory corruption) or have unspecified other impact via vectors related to use of __set, __get, __isset, and __unset methods on objects accessed by a reference.
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Analysis
by VulDB Data Team • 10/12/2021
The CVE-2010-4697 vulnerability represents a critical use-after-free flaw within the Zend engine of PHP, affecting versions prior to 5.2.15 and 5.3.4. This vulnerability stems from improper memory management during object reference handling, specifically when utilizing magic methods such as __set, __get, __isset, and __unset. The flaw occurs when PHP objects are accessed through references and subsequently manipulated using these special methods, creating conditions where freed memory locations may be accessed or reused, leading to unpredictable behavior and potential system compromise.
The technical implementation of this vulnerability exploits the interaction between PHP's object reference system and its garbage collection mechanisms within the Zend engine. When an object is referenced and then modified through magic methods, the engine fails to properly track the object's lifecycle, creating scenarios where memory allocated to an object can be freed while references to it still exist. This improper memory management allows attackers to manipulate the heap memory structure, potentially leading to heap corruption that can be exploited for more severe consequences beyond simple denial of service.
The operational impact of CVE-2010-4697 extends beyond simple denial of service to include potential heap memory corruption that could enable arbitrary code execution or privilege escalation. Attackers can leverage this vulnerability to corrupt heap memory structures, potentially causing application crashes or more dangerous outcomes such as remote code execution. The context-dependent nature of the vulnerability means that exploitation requires specific conditions involving object references and magic method usage, making it particularly challenging to detect and prevent without comprehensive code analysis and proper input validation.
This vulnerability aligns with CWE-416, which addresses use-after-free conditions, and demonstrates characteristics consistent with the attack patterns documented in the MITRE ATT&CK framework under software exploitation techniques. The flaw particularly affects web applications running PHP versions vulnerable to this issue, making it a significant concern for organizations maintaining legacy PHP applications. The vulnerability's exploitation potential is heightened in environments where PHP applications handle untrusted input or where objects are manipulated through user-controlled data flows, creating multiple attack vectors for malicious actors to leverage.
Organizations should prioritize immediate patching of affected PHP installations to address this vulnerability, as the use-after-free condition creates opportunities for both denial of service attacks and potential remote code execution. Additionally, implementing proper input validation and sanitization measures, along with regular security assessments of PHP applications, can help mitigate the risk of exploitation. The vulnerability underscores the importance of maintaining up-to-date software versions and following secure coding practices when working with PHP object-oriented features and reference handling mechanisms.