CVE-2013-4900 in Twilight
Summary
by MITRE
Directory traversal vulnerability in DeWeS web server 0.4.2 and possibly earlier, as used in Twilight CMS, allows remote attackers to read arbitrary files via a ..%5c (dot dot encoded backslash) in a GET request.
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Analysis
by VulDB Data Team • 02/22/2025
The CVE-2013-4900 vulnerability represents a critical directory traversal flaw in the DeWeS web server version 0.4.2 and potentially earlier iterations that was integrated into the Twilight CMS platform. This vulnerability stems from inadequate input validation within the web server's file handling mechanisms, specifically failing to properly sanitize or normalize path traversal sequences in HTTP GET requests. The flaw manifests when attackers exploit the server's inability to correctly interpret encoded directory traversal sequences, particularly the ..%5c pattern where %5c represents the backslash character in URL encoding. This vulnerability operates at the application layer and affects the web server's core file access functionality, making it a significant concern for any system utilizing the affected software components.
The technical exploitation of this vulnerability occurs through carefully crafted HTTP GET requests that include the ..%5c sequence, which when processed by the vulnerable DeWeS web server, allows attackers to traverse directory structures and access files outside the intended web root directory. The vulnerability's impact extends beyond simple information disclosure as it provides attackers with unrestricted access to the underlying file system, potentially enabling them to retrieve sensitive configuration files, database credentials, application source code, or other confidential data stored on the server. This type of vulnerability is categorized as a CWE-22 directory traversal weakness, which falls under the broader category of path traversal attacks that have been consistently identified as one of the most prevalent and dangerous web application security flaws by organizations such as OWASP and the SANS Institute. The vulnerability's exploitation aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing) as attackers can use this access to gather intelligence for further attacks.
The operational impact of CVE-2013-4900 is severe and multifaceted, as it provides remote attackers with unauthorized access to the entire file system of the affected server. This access can be leveraged to extract sensitive information, modify or delete critical files, and potentially establish persistent access through the deployment of backdoors or web shells. The vulnerability's remote nature means that attackers do not require physical access or prior authentication to exploit it, making it particularly dangerous for publicly accessible web servers. Organizations using Twilight CMS with the vulnerable DeWeS web server face significant risk of data breaches, system compromise, and potential regulatory violations depending on the nature of the data accessed. The vulnerability's presence in a widely used CMS platform amplifies its impact, as it affects numerous websites and applications that may not have proper security monitoring in place to detect such attacks, making it a prime target for automated exploitation tools and malicious actors seeking to compromise web infrastructure.
Mitigation strategies for CVE-2013-4900 should focus on immediate remediation through software updates and patches provided by the DeWeS web server developers or Twilight CMS maintainers. Organizations should implement comprehensive input validation at multiple layers of their application architecture, including web server configuration, application code, and network security controls. Network-based mitigations can include implementing web application firewalls that can detect and block malicious path traversal patterns, while application-level protections should enforce strict file access controls and normalize all file paths before processing. Security configurations should disable unnecessary file access capabilities and implement proper access control lists that prevent traversal beyond designated directories. Additionally, organizations should conduct thorough security assessments of their web applications to identify similar vulnerabilities in other components and establish monitoring procedures to detect potential exploitation attempts. The remediation process should also include updating to supported versions of Twilight CMS and DeWeS web server, as older versions may contain additional unpatched vulnerabilities that could be exploited in conjunction with CVE-2013-4900. Regular security audits and penetration testing should be implemented to ensure that similar vulnerabilities are not present in other web server components or application logic that could provide attackers with alternative paths to compromise the system.