CVE-2003-0282 in WinRar
Summary
by MITRE
Directory traversal vulnerability in UnZip 5.50 allows attackers to overwrite arbitrary files via invalid characters between two . (dot) characters, which are filtered and result in a ".." sequence.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2003-0282 represents a directory traversal flaw within UnZip version 5.50 that exploits improper input validation mechanisms. This weakness resides in how the decompression utility processes archive entries containing specially crafted filenames with invalid characters placed between consecutive dot characters. The vulnerability specifically targets the filtering logic that is designed to block malicious ".." sequences used for directory traversal attacks. When an attacker constructs a filename with invalid characters between dots, the system's sanitization process fails to properly handle these sequences, allowing the traversal logic to interpret the malformed input as a legitimate directory traversal attempt. This flaw demonstrates a classic case of insufficient input validation where the software does not adequately sanitize user-supplied data before processing it within the file system context.
The technical implementation of this vulnerability stems from the flawed interpretation of filename sequences within the UnZip utility's decompression engine. The software's filename validation routine removes or filters certain characters but does not account for the specific scenario where invalid characters are strategically positioned between dot characters. When the system encounters a filename such as "file..invalid..name" where invalid characters replace the standard dot separators, the filtering mechanism incorrectly processes these sequences, potentially reconstructing a valid ".." traversal pattern. This behavior creates a path traversal condition that allows attackers to manipulate the target location of extracted files beyond the intended extraction directory. The vulnerability operates at the application level and specifically affects the file system interaction components that handle archive decompression operations.
The operational impact of this directory traversal vulnerability extends beyond simple file overwrites to potentially compromise entire system security post-exploitation. An attacker who successfully exploits this vulnerability can overwrite critical system files, configuration files, or files in other directories accessible to the UnZip process. The severity of this attack vector increases when the UnZip utility runs with elevated privileges or when processing archives from untrusted sources. The vulnerability enables attackers to perform unauthorized file system modifications, potentially leading to privilege escalation, data corruption, or system compromise. This weakness also aligns with common attack patterns documented in the attack phase of the kill chain where adversaries seek to establish persistent access or cause system disruption through file system manipulation.
Mitigation strategies for CVE-2003-0282 should focus on immediate software updates and enhanced input validation measures. The most effective immediate solution involves upgrading to a patched version of UnZip that properly handles filename validation and sanitization. Organizations should also implement strict file name validation policies that reject any input containing potentially malicious sequences, including multiple consecutive dots or invalid character combinations. The implementation of secure coding practices should include comprehensive input sanitization routines that normalize all file paths before processing, preventing the reconstruction of directory traversal sequences. Additionally, system administrators should consider implementing file system access controls that limit the privileges of applications processing untrusted archives, reducing the potential impact of successful exploitation. This vulnerability aligns with CWE-22 directory traversal weakness and follows attack patterns described in MITRE ATT&CK technique T1059 for execution and T1070 for file and directory permissions. Organizations should also consider network-level controls that prevent the execution of potentially malicious archives from untrusted sources, implementing additional layers of defense to protect against this and similar path traversal vulnerabilities.