CVE-2015-1577 in U5cms
Summary
by MITRE
Directory traversal vulnerability in u5admin/deletefile.php in u5CMS before 3.9.4 allows remote attackers to write to arbitrary files via a (1) .. (dot dot) or (2) full pathname in the f parameter.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2015-1577 represents a critical directory traversal flaw within the u5CMS content management system prior to version 3.9.4. This weakness exists in the file deletion functionality of the administrative interface, specifically in the deletefile.php script that handles file operations. The vulnerability stems from inadequate input validation and sanitization mechanisms that fail to properly restrict user-supplied file paths, creating an opportunity for malicious actors to manipulate the system's file handling behavior.
The technical exploitation of this vulnerability occurs through the manipulation of the f parameter within the deletefile.php script. Attackers can leverage directory traversal sequences such as .. (dot dot) or provide full pathnames to bypass normal file access controls and gain unauthorized access to the file system. This allows remote attackers to write to arbitrary files on the server, potentially leading to complete system compromise. The vulnerability specifically affects the administrative interface, making it particularly dangerous as it provides access to sensitive system files and configuration data that could be used to escalate privileges or establish persistent access.
The operational impact of this vulnerability extends beyond simple file manipulation, as it creates a pathway for attackers to potentially execute arbitrary code, modify critical system components, or exfiltrate sensitive data. When combined with other vulnerabilities or reconnaissance efforts, this directory traversal flaw can serve as a foundational attack vector for more sophisticated compromises. The vulnerability affects the core functionality of the u5CMS system and represents a failure in input validation that violates fundamental security principles. According to CWE classification, this corresponds to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The attack surface is particularly concerning given that the vulnerability resides in the administrative component of the CMS, meaning that successful exploitation could provide attackers with access to sensitive administrative functions. The ability to write to arbitrary files through this vulnerability means that attackers could potentially upload malicious files, modify existing system files, or create backdoor access points. This vulnerability aligns with ATT&CK technique T1059, which covers command and scripting interpreter, as attackers could leverage the file manipulation capabilities to establish persistent access or execute commands on the compromised system. The weakness demonstrates a failure in the principle of least privilege and proper input validation, which are fundamental requirements for secure application development.
Mitigation strategies for CVE-2015-1577 require immediate patching of the u5CMS system to version 3.9.4 or later, which includes proper input validation and sanitization mechanisms. Organizations should implement strict input validation on all user-supplied parameters, particularly those used in file operations, and enforce proper path validation to prevent directory traversal attacks. Additional protective measures include implementing web application firewalls, restricting administrative access to trusted networks, and conducting regular security assessments of CMS components. The vulnerability highlights the importance of proper secure coding practices and input validation, which are essential for preventing similar issues in other applications. Organizations should also consider implementing automated monitoring for suspicious file operations and establishing incident response procedures specifically designed to address directory traversal attacks.