CVE-2010-2225 in PHP
Summary
by MITRE
Use-after-free vulnerability in the SplObjectStorage unserializer in PHP 5.2.x and 5.3.x through 5.3.2 allows remote attackers to execute arbitrary code or obtain sensitive information via serialized data, related to the PHP unserialize function.
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Analysis
by VulDB Data Team • 09/18/2021
The CVE-2010-2225 vulnerability represents a critical use-after-free flaw within PHP's SplObjectStorage class serialization mechanism, affecting versions 5.2.x through 5.3.2. This vulnerability specifically targets the unserialize function's handling of serialized data containing SplObjectStorage objects, creating a scenario where freed memory locations can be accessed and manipulated by remote attackers. The flaw occurs during the deserialization process when PHP attempts to reconstruct objects from their serialized representations, particularly when dealing with complex object structures that involve SplObjectStorage containers.
The technical nature of this vulnerability stems from improper memory management within PHP's internal object unserialization code. When a serialized SplObjectStorage object is processed, the system allocates memory for the object structure and its associated data elements. However, during the unserialization process, certain conditions cause the memory to be freed prematurely while still maintaining references to it. Attackers can craft malicious serialized data that exploits this timing issue, allowing them to manipulate the freed memory locations and potentially execute arbitrary code or extract sensitive information from the application's memory space. This type of vulnerability falls under the CWE-416 category of Use After Free, which is classified as a serious memory safety issue in software development.
The operational impact of this vulnerability is severe and far-reaching across web applications that utilize PHP's serialization features. Remote attackers can leverage this flaw to gain unauthorized code execution privileges on vulnerable systems, potentially leading to complete system compromise. The vulnerability enables attackers to perform various malicious activities including privilege escalation, data exfiltration, and persistent backdoor installation. Applications using PHP frameworks, content management systems, or any web applications that serialize user-provided data are at risk, particularly those that deserialize data from untrusted sources without proper validation. The attack vector is particularly dangerous because it can be exploited through standard HTTP requests containing malicious serialized data, making it accessible to attackers with minimal technical expertise.
Mitigation strategies for CVE-2010-2225 require immediate action from system administrators and developers to address the underlying vulnerability. The primary and most effective mitigation is to upgrade to PHP versions 5.3.3 or later, where the vulnerability has been patched in the core serialization code. Organizations should also implement strict input validation and sanitization practices for all serialized data, particularly when it originates from external sources. Additional protective measures include disabling unnecessary serialization functions, implementing proper access controls, and conducting regular security audits of application code that handles serialized data. The vulnerability demonstrates the critical importance of proper memory management in interpreted languages and aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage, as attackers can leverage the vulnerability to execute arbitrary commands through the compromised system. Security teams should also consider implementing runtime monitoring and intrusion detection systems to identify potential exploitation attempts, as this vulnerability can be used in combination with other attack vectors to achieve more sophisticated compromise scenarios.