CVE-2006-1963 in PCPIN Chat
Summary
by MITRE
Directory traversal vulnerability in main.php in PCPIN Chat 5.0.4 and earlier allows remote authenticated users to include and execute arbitrary PHP code via a ".." (dot dot) in a language cookie, as demonstrated by uploading then accessing a smiliefile image that actually contains PHP code.
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Analysis
by VulDB Data Team • 09/09/2017
The vulnerability identified as CVE-2006-1963 represents a critical directory traversal flaw within PCPIN Chat version 5.0.4 and earlier implementations. This security weakness specifically affects the main.php script which processes language cookie parameters without adequate input validation or sanitization. The vulnerability arises from the application's failure to properly validate user-supplied cookie data, creating an opportunity for attackers to manipulate file inclusion paths through crafted directory traversal sequences.
The technical exploitation of this vulnerability relies on the manipulation of the language cookie parameter to include directory traversal sequences using double dots "..". When an authenticated user accesses the application with a specially crafted cookie value containing these traversal sequences, the application processes the input and attempts to include files from unexpected locations within the filesystem. This flaw allows attackers to bypass normal file access controls and potentially execute arbitrary PHP code on the server, as demonstrated through the upload and execution of malicious smiliefile images that contain embedded PHP code.
From an operational impact perspective, this vulnerability enables authenticated attackers to escalate their privileges and gain unauthorized access to the server's file system. The attack vector requires authentication, which limits the scope of exploitation compared to unauthenticated vulnerabilities, but still represents a significant security risk within the application's access control model. The ability to execute arbitrary PHP code opens doors for data theft, system compromise, and potential lateral movement within the network infrastructure where the vulnerable application resides.
The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. This weakness falls under the broader category of input validation failures that can lead to arbitrary code execution and unauthorized file access. From an attacker's perspective, this vulnerability maps to multiple ATT&CK techniques including T1059 for execution through PHP code injection and T1083 for directory traversal operations. The attack chain typically begins with authentication, followed by cookie manipulation, and concludes with code execution through the vulnerable file inclusion mechanism.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and sanitization for all user-supplied data, particularly cookie parameters. The application should enforce strict path validation to prevent directory traversal sequences from being processed, and implement proper access controls to limit file inclusion to predefined safe directories. Additionally, the application should validate and sanitize all cookie values before processing, ensuring that any traversal sequences are removed or neutralized. Regular security updates and patch management procedures should be implemented to address similar vulnerabilities in third-party components and ensure that the application remains protected against known exploitation techniques.