CVE-2007-0389 in ArsDigita Community System
Summary
by MITRE
Directory traversal vulnerability in ArsDigita Community System (ACS) 3.4.10 and earlier, and ArsDigita Community Education Solution (ACES) 1.1, allows remote attackers to read arbitrary files via .%252e/ (double-encoded dot dot slash) sequences in the URI.
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Analysis
by VulDB Data Team • 01/06/2025
The vulnerability described in CVE-2007-0389 represents a classic directory traversal flaw that affects the ArsDigita Community System (ACS) version 3.4.10 and earlier, as well as the ArsDigita Community Education Solution (ACES) version 1.1. This type of vulnerability falls under the category of CWE-22 - Improper Limitation of a Pathname to a Restricted Directory, which is a fundamental security weakness in web application input validation. The flaw specifically manifests when the application fails to properly sanitize user-supplied input that contains path traversal sequences, allowing attackers to manipulate file access requests through carefully crafted URI parameters.
The technical implementation of this vulnerability exploits the way web servers and applications process double-encoded sequences such as .%252e/ which represents a double-encoded dot dot slash pattern. When an application receives a URI containing such sequences, it processes the first level of encoding and then attempts to resolve the directory traversal path. The ACS and ACES systems do not adequately handle this double encoding scenario, allowing attackers to bypass directory restriction mechanisms that would normally prevent access to files outside of intended directories. This occurs because the application's input validation routines fail to properly decode and sanitize the URI components before processing them, creating an opening for malicious file access attempts.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to access sensitive files that may contain database credentials, configuration settings, application source code, or other confidential data. Attackers can leverage this vulnerability to read system files, potentially gaining access to authentication tokens, database connection strings, or application configuration files that could lead to further exploitation. The vulnerability affects the core file access mechanisms of these applications, making it particularly dangerous as it can be exploited without requiring authentication or specific privileges. This type of attack aligns with ATT&CK technique T1083 - File and Directory Discovery, where adversaries seek to identify file systems and locate sensitive information.
Security practitioners should implement multiple layers of mitigation to address this vulnerability, starting with immediate patching of affected systems to the latest available versions of ACS and ACES that contain proper input validation. Additionally, web application firewalls should be configured to detect and block double-encoded sequences in URI parameters, particularly those containing dot dot slash patterns. Input validation routines should be strengthened to properly decode and sanitize all user-supplied URI components before processing, ensuring that directory traversal sequences are identified and rejected. Network segmentation and principle of least privilege access controls should also be implemented to limit the potential damage from successful exploitation attempts. The vulnerability demonstrates the importance of proper input sanitization and the dangers of inadequate encoding handling in web applications, making it a critical issue for any organization using these or similar legacy systems that may be susceptible to similar encoding-related vulnerabilities.