CVE-2005-2691 in RunCMS
Summary
by MITRE
includes/common.php in RunCMS 1.2 and earlier calls the extract function with EXTR_OVERWRITE on HTTP POST variables, which allows remote attackers to overwrite arbitrary variables, possibly allowing execution of arbitrary code.
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Analysis
by VulDB Data Team • 06/08/2019
The vulnerability described in CVE-2005-2691 represents a critical security flaw in RunCMS 1.2 and earlier versions that stems from improper input handling and variable manipulation. This issue occurs within the includes/common.php file where the PHP extract function is employed with the EXTR_OVERWRITE flag, creating a dangerous condition that can be exploited by remote attackers to manipulate the application's internal state. The vulnerability is classified under CWE-116 as "Improper Encoding or Escaping of Output" and aligns with ATT&CK technique T1190 "Exploit Public-Facing Application" as it targets a web application interface.
The technical implementation of this vulnerability involves the extract function processing HTTP POST variables without proper sanitization or validation, allowing attackers to inject malicious data that overwrites critical application variables. When EXTR_OVERWRITE is specified, any variable name present in the POST data can overwrite existing variables in the local scope, potentially compromising variables that control application flow, authentication status, or database connections. This creates a pathway for attackers to manipulate the application's execution environment and potentially achieve arbitrary code execution. The flaw directly relates to CWE-94 which describes "Improper Control of Generation of Code ('Code Injection')" and demonstrates how improper variable handling can lead to code execution vulnerabilities.
The operational impact of this vulnerability is severe as it provides remote attackers with the capability to manipulate application behavior and potentially gain unauthorized access to system resources. Attackers can leverage this vulnerability to overwrite variables that control user authentication, database connections, or file operations, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it can be exploited through standard web application interfaces without requiring special privileges or access to the server environment, making it a prime target for automated exploitation tools. This weakness enables attackers to bypass normal application security controls and execute malicious code within the application's context.
Mitigation strategies for this vulnerability involve multiple layers of security controls to prevent variable manipulation and code injection. The primary fix requires modifying the application code to eliminate the use of extract with EXTR_OVERWRITE flags, instead implementing proper input validation and explicit variable assignment. Organizations should implement proper parameter sanitization techniques and avoid dynamic variable creation from untrusted input sources. The remediation aligns with security best practices outlined in OWASP Top Ten and follows the principle of least privilege by ensuring that only expected variables are processed from user input. Additionally, regular security audits and code reviews should be conducted to identify similar patterns that could introduce similar vulnerabilities in other parts of the application. The fix should also include implementing proper input filtering mechanisms that validate and sanitize all HTTP POST variables before processing, ensuring that variable names match expected patterns and do not contain malicious content that could overwrite critical application variables.