CVE-2006-0869 in Pear Liveuser
Summary
by MITRE
Directory traversal vulnerability in the "remember me" feature in liveuser.php in PHP Extension and Application Repository (PEAR) LiveUser 0.16.8 and earlier allows remote attackers to determine file existence, and possibly delete arbitrary files with short pathnames or possibly read arbitrary files, via a .. (dot dot) in the store_id value of a cookie.
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Analysis
by VulDB Data Team • 08/05/2017
The vulnerability identified as CVE-2006-0869 represents a critical directory traversal flaw within the PHP Extension and Application Repository's PEAR LiveUser component version 0.16.8 and earlier. This security weakness specifically targets the "remember me" functionality implemented in the liveuser.php script, creating a pathway for malicious actors to exploit file system access controls through manipulated cookie values. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly handle special characters in the store_id parameter, allowing attackers to manipulate file paths through the use of directory traversal sequences.
The technical exploitation of this vulnerability occurs when an attacker manipulates the store_id value within the cookie data by inserting .. (dot dot) sequences that traverse the file system hierarchy. This flaw enables remote attackers to perform file existence checks and potentially execute unauthorized file operations including deletion of arbitrary files with short pathnames or reading of arbitrary files from the system. The vulnerability operates at the application level and demonstrates a classic path traversal attack pattern that bypasses normal file access restrictions by manipulating the relative path references.
From an operational impact perspective, this vulnerability poses significant risks to web applications utilizing the affected PEAR LiveUser component. Attackers can leverage this weakness to gain unauthorized access to sensitive system files, potentially leading to data exposure, system compromise, or further escalation attacks. The ability to determine file existence provides attackers with reconnaissance capabilities that can be used to map the target system's file structure, while the potential for file deletion creates opportunities for destructive attacks. The vulnerability affects the fundamental security model of the application by allowing attackers to bypass file access controls that should normally restrict path traversal operations.
The vulnerability aligns with CWE-22, which categorizes directory traversal attacks as a common weakness in software design that allows attackers to access files outside of intended directories. This weakness specifically manifests in the improper handling of input data through cookie manipulation, creating a pathway for privilege escalation and unauthorized system access. The attack vector follows patterns consistent with the MITRE ATT&CK framework's privilege escalation techniques, particularly those involving path traversal and file system manipulation. The vulnerability also demonstrates characteristics of the attack pattern described in the OWASP Top Ten, specifically related to insecure file handling and improper input validation.
Mitigation strategies for CVE-2006-0869 should prioritize immediate patching of the affected PEAR LiveUser component to version 0.16.9 or later, which contains the necessary fixes for the directory traversal vulnerability. Organizations should implement comprehensive input validation mechanisms that sanitize all cookie data, particularly parameters that may be used in file system operations. Additional protective measures include implementing proper path normalization techniques, restricting file access permissions, and employing web application firewalls to detect and block suspicious cookie manipulation attempts. The implementation of a robust security monitoring system that tracks unusual file access patterns and cookie manipulation activities can provide early detection of exploitation attempts. Organizations should also consider implementing principle of least privilege access controls and regular security audits to prevent similar vulnerabilities from emerging in other components of their web applications.