CVE-2011-2507 in phpMyAdmin
Summary
by MITRE
libraries/server_synchronize.lib.php in the Synchronize implementation in phpMyAdmin 3.x before 3.3.10.2 and 3.4.x before 3.4.3.1 does not properly quote regular expressions, which allows remote authenticated users to inject a PCRE e (aka PREG_REPLACE_EVAL) modifier, and consequently execute arbitrary PHP code, by leveraging the ability to modify the SESSION superglobal array.
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Analysis
by VulDB Data Team • 11/14/2021
The vulnerability identified as CVE-2011-2507 represents a critical security flaw in phpMyAdmin's server synchronization functionality that enables authenticated remote attackers to execute arbitrary PHP code through improper handling of regular expressions. This issue affects phpMyAdmin versions 3.x prior to 3.3.10.2 and 3.4.x prior to 3.4.3.1, making it a significant concern for organizations relying on these older versions of the popular database management tool. The vulnerability stems from inadequate input sanitization within the server_synchronize.lib.php library file, specifically in how regular expressions are processed during the synchronization implementation.
The technical flaw manifests when the synchronize functionality processes user-supplied data through the SESSION superglobal array, which can be modified by authenticated users. The vulnerability occurs because the application fails to properly quote or escape regular expression patterns before using them in PCRE functions, particularly allowing the PREG_REPLACE_EVAL modifier to be injected. This modifier, when enabled through malicious input, causes the preg_replace function to execute the replacement string as PHP code, creating a classic code injection vulnerability. The flaw is categorized under CWE-94, which represents "Improper Control of Generation of Code ('Code Injection')" and specifically aligns with CWE-77, "Improper Neutralization of Special Elements used in a Regular Expression" in the context of PHP's PCRE implementation.
The operational impact of this vulnerability is severe as it allows authenticated attackers to execute arbitrary PHP code on the target system, potentially leading to complete system compromise. An attacker with valid login credentials can manipulate the SESSION array to inject malicious regular expressions that trigger the PREG_REPLACE_EVAL modifier, thereby gaining unauthorized access to the server's file system, database contents, and potentially escalating privileges. This vulnerability directly maps to the ATT&CK technique T1059.006, "Command and Scripting Interpreter: PowerShell", and more broadly to T1190, "Exploit Public-Facing Application", as it exploits a flaw in a widely-used web application. The attack vector requires only authenticated access, making it particularly dangerous as it can be exploited by insiders or compromised legitimate users.
The recommended mitigation strategy involves immediate upgrading to phpMyAdmin versions 3.3.10.2 or 3.4.3.1, which contain the necessary patches to properly quote regular expressions and prevent the injection of the PREG_REPLACE_EVAL modifier. Organizations should also implement additional security measures such as monitoring for unusual SESSION modifications, implementing strict input validation for all user-supplied data, and considering the principle of least privilege for phpMyAdmin accounts. Network segmentation and web application firewalls can provide additional defense-in-depth layers, while regular security audits should verify that no other similar vulnerabilities exist in the application's codebase. The vulnerability also highlights the importance of proper error handling and input sanitization in PHP applications, particularly when dealing with regular expressions and user-controllable data, aligning with security best practices outlined in the OWASP Top Ten and NIST Cybersecurity Framework.