CVE-2011-4350 in Yaws
Summary
by MITRE
Yaws 1.91 has a directory traversal vulnerability in the way certain URLs are processed. A remote authenticated user could use this flaw to obtain content of arbitrary local files via specially-crafted URL request.
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Analysis
by VulDB Data Team • 09/01/2024
The vulnerability identified as CVE-2011-4350 affects Yaws version 1.91 and represents a critical directory traversal flaw in the web server's URL processing mechanism. This vulnerability stems from insufficient input validation and sanitization of URL requests, allowing authenticated remote attackers to exploit the system's file handling capabilities. The flaw specifically manifests when the application processes certain URL patterns without proper boundary checks, enabling attackers to manipulate file paths and access unauthorized local resources.
This directory traversal vulnerability falls under the CWE-22 category, which specifically addresses "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')". The technical implementation flaw occurs at the application layer where user-supplied URL parameters are directly incorporated into file system operations without adequate sanitization or validation. The vulnerability is classified as a remote authenticated attack vector, meaning that an attacker must first establish authentication credentials to the system, but once authenticated, they can leverage this flaw to access arbitrary files on the server's file system.
The operational impact of this vulnerability is severe as it provides attackers with the ability to read sensitive files that may contain configuration data, user credentials, application source code, or other confidential information. Attackers can exploit this flaw by crafting malicious URL requests containing directory traversal sequences such as "../" or "..\\", which when processed by the vulnerable Yaws server, allow access to files outside the intended web root directory. This capability can lead to complete system compromise, data exfiltration, and potential lateral movement within the network infrastructure. The vulnerability essentially undermines the fundamental security principle of least privilege by allowing authenticated users to bypass normal file access controls.
Mitigation strategies for CVE-2011-4350 should focus on immediate patching of the Yaws server to version 1.92 or later, which contains the necessary fixes for the directory traversal vulnerability. Additionally, administrators should implement proper input validation and sanitization at all points where user-supplied data is processed, particularly in URL handling components. Network segmentation and firewall rules can help limit the attack surface by restricting access to the vulnerable server. The implementation of web application firewalls and security monitoring systems can also detect and block suspicious URL patterns attempting directory traversal attacks. Organizations should also conduct regular security assessments and vulnerability scanning to identify similar flaws in other applications and systems. This vulnerability aligns with several ATT&CK techniques including T1083 (File and Directory Discovery) and T1566 (Phishing with Malicious Attachments) where attackers might leverage such flaws to obtain sensitive information. The remediation process should include thorough testing of patched systems to ensure that the fix does not introduce regressions while maintaining the application's intended functionality and user access controls.