CVE-2011-2744 in Chyrp
Summary
by MITRE
Directory traversal vulnerability in Chyrp 2.1 and earlier allows remote attackers to include and execute arbitrary local files via a ..%2F (encoded dot dot slash) in the action parameter to the default URI.
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability described in CVE-2011-2744 represents a critical directory traversal flaw affecting Chyrp 2.1 and earlier versions of the content management system. This vulnerability resides in the application's handling of user-supplied input within the action parameter of the default URI, creating an opportunity for remote attackers to manipulate file inclusion mechanisms. The issue stems from insufficient input validation and sanitization, allowing malicious actors to exploit the system's file handling capabilities through encoded directory traversal sequences.
The technical exploitation of this vulnerability leverages the ..%2F encoding pattern where %2F represents the forward slash character in URL encoding. When the application processes this encoded sequence in the action parameter, it fails to properly sanitize or validate the input before using it in file inclusion operations. This allows attackers to navigate directories beyond the intended scope and access arbitrary local files on the server. The vulnerability specifically targets the default URI handling mechanism, making it particularly dangerous as it affects the core application functionality that users interact with regularly.
The operational impact of this directory traversal vulnerability extends beyond simple information disclosure to potentially enable full system compromise. Remote attackers can leverage this flaw to execute arbitrary code on the affected server by including and executing local files, which may include system configuration files, database credentials, or even backdoor scripts. This represents a severe security risk that can lead to complete system takeover, data breaches, and unauthorized access to sensitive information stored within the application's environment. The vulnerability affects the application's integrity and confidentiality, potentially allowing attackers to escalate privileges and maintain persistent access.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization mechanisms. The primary defense involves ensuring that all user-supplied input, particularly in parameters used for file operations, undergoes strict validation to prevent directory traversal sequences. Implementing a whitelist-based approach for acceptable action parameters and employing proper path normalization techniques can effectively prevent exploitation attempts. Organizations should also consider implementing web application firewalls to detect and block suspicious encoded sequences, while maintaining up-to-date security patches for the Chyrp CMS. Regular security audits and input validation testing should be conducted to identify similar vulnerabilities in other components of the application stack.
This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal. The ATT&CK framework categorizes this as a technique for privilege escalation and lateral movement, where adversaries exploit path traversal vulnerabilities to access restricted files and potentially gain system-level access. The vulnerability demonstrates the critical importance of secure coding practices and input validation in preventing remote code execution through file inclusion mechanisms. Organizations should also consider implementing principle of least privilege access controls and regular security assessments to identify and remediate similar vulnerabilities across their software ecosystems.