CVE-2003-0539 in skk
Summary
by MITRE
skk (Simple Kana to Kanji conversion program) 12.1 and earlier, and the ddskk package which is based on skk, creates temporary files insecurely, which allows local users to overwrite arbitrary files.
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Analysis
by VulDB Data Team • 09/29/2018
The vulnerability identified as CVE-2003-0539 affects skk (Simple Kana to Kanji conversion program) versions 12.1 and earlier, as well as the ddskk package derived from skk. This represents a critical insecure temporary file creation flaw that enables local attackers to overwrite arbitrary files on the system. The vulnerability stems from improper handling of temporary files during the conversion process, where the program does not adequately secure the creation and management of temporary files that are essential for processing kana to kanji conversions.
The technical implementation of this vulnerability involves the insecure creation of temporary files without proper permissions or atomic operations. When skk processes input data for kana to kanji conversion, it generates temporary files that are typically stored in predictable locations with insufficient access controls. Attackers can exploit this by creating symbolic links or by pre-creating files in the temporary directory with specific names, allowing them to manipulate the temporary file creation process and ultimately overwrite files of their choice. This type of vulnerability falls under CWE-377, which specifically addresses insecure temporary file creation, and represents a classic example of a race condition or privilege escalation vector.
The operational impact of this vulnerability is significant for systems utilizing skk or ddskk for Japanese text processing. Local users with minimal privileges can potentially overwrite critical system files, configuration files, or even executable programs, leading to privilege escalation or system compromise. The vulnerability affects environments where these conversion tools are used for text processing, web applications, or any system requiring kana to kanji conversion functionality. Given that this vulnerability existed in widely deployed versions of the software, it could have been exploited across numerous systems without proper patching or mitigation measures.
Mitigation strategies for this vulnerability should focus on immediate patching of affected versions to ensure secure temporary file creation practices. Organizations should implement proper temporary file handling mechanisms that include using secure file creation functions with appropriate permissions, employing atomic file operations, and ensuring that temporary files are created with restricted access controls. Additionally, system administrators should consider implementing file system monitoring to detect unauthorized file modifications and ensure that the affected software is updated to versions that address the insecure temporary file creation flaw. This vulnerability demonstrates the importance of proper file handling security practices and aligns with ATT&CK technique T1059.007 for execution through command-line interfaces, where local privilege escalation could be achieved through file overwrite attacks.