CVE-2004-0792 in rsync
Summary
by MITRE
Directory traversal vulnerability in the sanitize_path function in util.c for rsync 2.6.2 and earlier, when chroot is disabled, allows attackers to read or write certain files.
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Analysis
by VulDB Data Team • 03/09/2021
The vulnerability identified as CVE-2004-0792 represents a critical directory traversal flaw within the rsync file synchronization utility version 2.6.2 and earlier. This vulnerability specifically affects the sanitize_path function located in the util.c source file, which plays a crucial role in path validation and normalization during file operations. The flaw becomes particularly dangerous when rsync operates without chroot isolation, creating an environment where malicious actors can exploit the inadequate path sanitization mechanisms to gain unauthorized access to system resources. This vulnerability directly impacts the integrity and confidentiality of file systems by allowing attackers to bypass normal access controls and potentially access restricted directories or files.
The technical implementation of this directory traversal vulnerability stems from insufficient input validation within the sanitize_path function, which fails to properly normalize or validate file paths before processing them. When rsync processes file operations without chroot protection, the function does not adequately strip or reject potentially malicious path sequences such as double dots or backslash combinations that could lead to directory traversal. Attackers can exploit this weakness by crafting specially formatted file paths that contain sequences like "../" or similar traversal patterns, enabling them to navigate outside the intended directory boundaries and access files that should normally be restricted. This vulnerability operates at the application layer and specifically targets the path handling mechanisms of rsync, making it a prime example of a flaw that violates the principle of least privilege and proper input validation.
The operational impact of CVE-2004-0792 extends beyond simple unauthorized file access, as it provides attackers with the capability to potentially modify system files or read sensitive data from locations outside the intended scope of rsync operations. This vulnerability can be exploited to read system configuration files, password files, or other sensitive information that may be stored outside the normal rsync working directories. Additionally, the ability to write to arbitrary locations within the file system creates opportunities for privilege escalation or persistent malicious modifications to system resources. The vulnerability's exploitation typically requires minimal privileges and can be executed through standard rsync client operations, making it particularly dangerous in environments where rsync is used for file synchronization across networks. This flaw aligns with CWE-22 directory traversal vulnerabilities and represents a classic example of insufficient input validation that can lead to unauthorized access and data compromise.
Security mitigation strategies for this vulnerability primarily focus on immediate patching and system hardening measures. The most effective solution involves upgrading to rsync version 2.6.3 or later, where the sanitize_path function has been properly modified to address the path traversal issues. Organizations should also implement proper chroot isolation for rsync operations when possible, as this provides an additional layer of protection against directory traversal attacks. Network segmentation and access controls should be enforced to limit rsync exposure to trusted networks and users. The vulnerability demonstrates the importance of proper input validation and path normalization, principles that align with defense-in-depth strategies recommended by cybersecurity frameworks. System administrators should also consider implementing monitoring and logging for rsync operations to detect potential exploitation attempts, as this vulnerability can be used for reconnaissance and privilege escalation activities that align with various attack patterns described in the MITRE ATT&CK framework under the privilege escalation and defense evasion categories.