CVE-2012-2335 in PHP
Summary
by MITRE
php-wrapper.fcgi does not properly handle command-line arguments, which allows remote attackers to bypass a protection mechanism in PHP 5.3.12 and 5.4.2 and execute arbitrary code by leveraging improper interaction between the PHP sapi/cgi/cgi_main.c component and a query string beginning with a +- sequence.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability identified as CVE-2012-2335 represents a critical command-line argument handling flaw in PHP's FastCGI interface implementation. This security issue affects PHP versions 5.3.12 and 5.4.2, where the php-wrapper.fcgi component fails to properly validate or sanitize command-line arguments passed to the PHP CGI interface. The flaw stems from improper interaction between the PHP Server API (SAPI) CGI module and query string parsing mechanisms, creating a pathway for malicious input to bypass intended security protections. The vulnerability specifically exploits the way the CGI main component processes input parameters, allowing attackers to manipulate the argument parsing logic through carefully crafted query strings that begin with a plus sign sequence.
The technical exploitation of this vulnerability occurs through the manipulation of query string parameters in FastCGI requests where the initial characters of the query string begin with a plus (+) symbol. This specific character sequence triggers a parsing inconsistency in the cgi_main.c component where the argument handling logic fails to properly distinguish between legitimate command-line parameters and malicious input. The flaw essentially allows attackers to inject arbitrary command-line arguments that can be interpreted by the PHP interpreter, bypassing the normal security mechanisms designed to prevent such code execution. This type of vulnerability falls under the CWE-134 category of Uncontrolled Format String, specifically related to improper input validation in CGI environments.
The operational impact of CVE-2012-2335 is severe as it enables remote code execution on vulnerable systems without requiring authentication or privileged access. Attackers can leverage this vulnerability to execute arbitrary commands on the web server hosting vulnerable PHP applications, potentially leading to complete system compromise. The vulnerability is particularly dangerous in shared hosting environments or when PHP is configured in CGI mode, as it allows attackers to bypass typical security restrictions that would normally prevent command execution. This type of remote code execution capability places the vulnerability in the ATT&CK framework under the T1059.007 technique for Command and Scripting Interpreter, specifically focusing on CGI-based execution methods. The vulnerability also aligns with T1190 for Exploit Public-Facing Application, as it represents an exploitable weakness in a widely deployed web application interface.
Mitigation strategies for CVE-2012-2335 primarily involve upgrading to patched versions of PHP where the argument handling logic has been corrected. System administrators should immediately update their PHP installations to versions 5.3.13 or 5.4.3, which contain the necessary fixes for this vulnerability. Additionally, implementing proper input validation at the web server level can provide additional defense-in-depth measures, though this approach should not be considered a complete solution. Organizations should also consider configuring their FastCGI interfaces to properly sanitize input parameters and implement network-level restrictions to limit access to PHP CGI interfaces. The vulnerability highlights the importance of proper input validation in CGI environments and serves as a reminder of the critical security implications of improper argument handling in server-side scripting interfaces.