CVE-2004-1487 in wget
Summary
by MITRE
wget 1.8.x and 1.9.x allows a remote malicious web server to overwrite certain files via a redirection URL containing a ".." that resolves to the IP address of the malicious server, which bypasses wget s filtering for ".." sequences.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/02/2019
The vulnerability identified as CVE-2004-1487 represents a significant file system traversal flaw in wget versions 1.8.x and 1.9.x that enables remote attackers to manipulate file download operations through carefully crafted redirection URLs. This security weakness stems from inadequate validation of directory traversal sequences within URL redirection paths, specifically failing to properly filter or reject ".." sequences that could potentially resolve to malicious server IP addresses rather than being properly sanitized. The vulnerability operates at the application layer and specifically targets the file system interaction mechanisms employed by wget during HTTP redirection processes, making it particularly dangerous as it can be exploited through standard web server responses without requiring any special privileges or authentication.
The technical exploitation of this vulnerability occurs when wget encounters a redirection response from a malicious web server that contains directory traversal sequences pointing to locations outside the intended download directory. The flaw lies in wget's handling of these redirection paths where the software fails to adequately sanitize or validate the presence of ".." sequences in the URL path components. When a malicious server responds with a redirect that includes these traversal sequences, wget processes them without proper validation, allowing the download operation to proceed to locations outside the intended target directory. This behavior creates a path traversal condition that can potentially overwrite critical system files or place malicious content in unintended locations, with the attacker leveraging the redirection to bypass wget's built-in filtering mechanisms designed to prevent such operations.
The operational impact of CVE-2004-1487 extends beyond simple file overwrites as it provides attackers with a method to manipulate the file system state of systems running vulnerable versions of wget. This vulnerability can be exploited in various scenarios including automated download scripts, system administration tasks, and web-based content retrieval operations where wget is used to fetch resources from untrusted sources. The attack vector is particularly concerning because it can be executed through standard HTTP redirect mechanisms that are commonly encountered in web browsing and automated downloading processes. Systems that rely on wget for downloading content from potentially malicious sources become vulnerable to this attack, potentially allowing attackers to overwrite configuration files, executables, or other critical system components. The vulnerability is classified under CWE-22 as a directory traversal attack, specifically involving improper input validation of path traversal sequences.
Mitigation strategies for this vulnerability require immediate patching of affected wget versions to address the directory traversal filtering mechanism. Organizations should upgrade to wget versions that properly validate and sanitize URL redirection paths, ensuring that ".." sequences are appropriately rejected or resolved within safe boundaries. System administrators should implement network-level controls to monitor and restrict wget operations to trusted sources, and consider implementing additional validation layers for automated download processes. The mitigation approach aligns with defensive techniques outlined in the ATT&CK framework under the execution and privilege escalation domains, where proper input validation and secure file system operations are critical defense mechanisms. Organizations should also consider implementing web application firewalls or proxy configurations that can detect and block malicious redirection patterns before they reach systems running vulnerable wget versions. Regular security audits of download operations and network configurations should be performed to identify and remediate potential exposure to this class of vulnerability.