CVE-2007-4843 in Unreal Commander
Summary
by MITRE
Directory traversal vulnerability in X-Diesel Unreal Commander 0.92 build 565 and 573 allows remote FTP servers to create or overwrite arbitrary files via a .. (dot dot) in a filename. NOTE: this can be leveraged for code execution by writing to a Startup folder.
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Analysis
by VulDB Data Team • 11/02/2017
The directory traversal vulnerability identified as CVE-2007-4843 affects X-Diesel Unreal Commander version 0.92 build 565 and 573, representing a critical security flaw that enables remote attackers to manipulate file system operations through carefully crafted filenames containing dot-dot sequences. This vulnerability resides in the application's handling of filenames received from remote FTP servers, where the software fails to properly validate or sanitize directory path references before processing file operations. The flaw specifically manifests when the application encounters filenames containing .. (dot dot) sequences that should normally be rejected or properly resolved to prevent directory traversal attacks.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the file handling routines of Unreal Commander. When processing filenames from FTP servers, the application does not adequately sanitize or normalize path references that contain directory traversal sequences, allowing attackers to bypass normal file system access controls. This weakness enables attackers to specify arbitrary file paths that can result in file creation or overwrites in directories outside the intended scope of the application's file operations. The vulnerability is particularly dangerous because it allows attackers to write files to system directories, including those that could be executed by the operating system.
The operational impact of this vulnerability extends beyond simple file manipulation to potentially enable full system compromise through code execution. When combined with appropriate attack vectors, particularly those involving writing files to system startup folders, this vulnerability can be leveraged to establish persistent backdoors or execute malicious code with the privileges of the user running the Unreal Commander application. The attack chain typically involves an attacker controlling a remote FTP server, crafting malicious filenames with directory traversal sequences, and then triggering the vulnerable application to process these files, resulting in unauthorized file creation or modification in critical system locations.
Security professionals should note that this vulnerability aligns with CWE-22, which specifically addresses directory traversal or path traversal flaws in software systems. The ATT&CK framework categorizes this type of vulnerability under T1059, which covers command and scripting interpreters, as attackers can leverage such flaws to execute code through malicious file placement. The vulnerability also demonstrates characteristics of T1547, representing persistence mechanisms, since successful exploitation can result in files being placed in startup folders or other persistent locations. Organizations should implement immediate mitigations including updating to patched versions of Unreal Commander, implementing network segmentation to limit FTP server access, and deploying intrusion detection systems to monitor for suspicious filename patterns containing directory traversal sequences.
The remediation strategy for this vulnerability requires immediate patching of affected Unreal Commander installations to version 0.92 build 575 or later, which contains the necessary input validation fixes. Additionally, system administrators should implement network access controls to restrict FTP server communications, particularly when dealing with untrusted sources. The vulnerability highlights the importance of proper input validation and sanitization in file handling operations, emphasizing that all external filename inputs should be normalized and validated against a whitelist of acceptable characters and patterns. Regular security audits should include verification of file system access controls and monitoring for unauthorized file system modifications in critical directories, particularly those related to application startup and execution paths.