CVE-2006-6581 in Php Debug
Summary
by MITRE
PHP remote file inclusion vulnerability in tests/debug_test.php in Vernet Loic PHP_Debug 1.1.0 allows remote attackers to execute arbitrary PHP code via a URL in the debugClassLocation parameter.
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Analysis
by VulDB Data Team • 09/28/2017
The vulnerability identified as CVE-2006-6581 represents a critical remote file inclusion flaw within the PHP_Debug 1.1.0 library developed by Vernet Loic. This vulnerability exists in the tests/debug_test.php file and demonstrates a classic security weakness that has been documented in numerous security frameworks including CWE-88 and CWE-94. The flaw allows remote attackers to inject malicious URLs into the debugClassLocation parameter, which then gets processed by the application without proper validation or sanitization, creating an avenue for arbitrary code execution.
The technical implementation of this vulnerability stems from improper input validation within the PHP_Debug library's debugging functionality. When the debug_test.php script processes the debugClassLocation parameter, it fails to sanitize user-supplied input before using it in file inclusion operations. This creates a condition where an attacker can manipulate the parameter to point to external malicious PHP scripts hosted on remote servers. The vulnerability is particularly dangerous because it allows attackers to execute arbitrary PHP code on the target server, potentially leading to complete system compromise. This type of vulnerability falls under the ATT&CK technique T1190 - Exploit Public-Facing Application, as it targets a publicly accessible web application component.
The operational impact of this vulnerability is severe and multifaceted. An attacker exploiting this flaw can gain unauthorized access to the affected system, potentially leading to data theft, system modification, or complete server compromise. The vulnerability affects any system running PHP_Debug 1.1.0 and has been widely exploited in the wild since its disclosure. The remote nature of the attack means that exploitation can occur from anywhere on the internet without requiring physical access to the target system. This vulnerability also represents a significant risk to web application security posture, as it demonstrates how seemingly innocuous debugging features can become attack vectors when not properly secured. Organizations using this library face potential exposure to credential theft, service disruption, and unauthorized data access, making this a critical security concern that requires immediate remediation.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected PHP_Debug library to version 1.1.1 or later, which contains the necessary security fixes. Additionally, administrators should implement input validation measures to sanitize all user-supplied parameters before processing, particularly those used in file inclusion operations. The implementation of web application firewalls and security monitoring systems can help detect and prevent exploitation attempts. Security best practices recommend avoiding the use of user-controllable variables in file inclusion operations and implementing proper access controls to limit the exposure of debugging components in production environments. Organizations should also conduct regular security assessments to identify similar vulnerabilities in their application code and dependencies, as this type of flaw is commonly found in legacy applications and libraries that have not been properly maintained or updated.