CVE-2000-0607 in KON
Summary
by MITRE
Buffer overflow in fld program in Kanji on Console (KON) package on Linux may allow local users to gain root privileges via an input file containing long CHARSET_REGISTRY or CHARSET_ENCODING settings.
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Analysis
by VulDB Data Team • 11/30/2024
The vulnerability identified as CVE-2000-0607 represents a critical buffer overflow flaw within the fld program of the Kanji on Console KON package running on Linux systems. This security weakness specifically targets the handling of CHARSET_REGISTRY and CHARSET_ENCODING parameters within input files, creating an opportunity for local attackers to escalate their privileges to root level access. The vulnerability stems from inadequate input validation and bounds checking within the program's processing of kanji character encoding specifications, which are essential for proper text rendering in console environments.
The technical implementation of this buffer overflow occurs when the fld program processes input files containing excessively long CHARSET_REGISTRY or CHARSET_ENCODING settings. The program fails to properly validate the length of these parameters before copying them into fixed-size buffers, allowing attackers to overwrite adjacent memory locations. This memory corruption can be strategically exploited to overwrite return addresses, function pointers, or other critical program state information, enabling arbitrary code execution. The flaw is particularly dangerous because it operates within a privileged context where the program may be running with elevated permissions, making successful exploitation directly translate to root privilege acquisition.
From an operational perspective, this vulnerability presents a significant risk to Linux systems utilizing the KON package for kanji character support. Local users who can create or modify input files processed by the fld program can leverage this weakness to execute malicious code with system-level privileges. The attack vector is relatively straightforward as it requires only local access and the ability to manipulate input files, making it particularly concerning for multi-user systems where privilege separation is crucial. The vulnerability demonstrates how seemingly innocuous character encoding processing can become a gateway for system compromise, highlighting the importance of robust input validation in all system components.
The security implications extend beyond simple privilege escalation, as this vulnerability aligns with several ATT&CK tactics including privilege escalation and defense evasion. The CWE classification for this issue would fall under CWE-121, which describes stack-based buffer overflow conditions, and potentially CWE-787, representing out-of-bounds write vulnerabilities. Mitigation strategies should include immediate patching of the KON package to implement proper input length validation and buffer boundary checks. System administrators should also consider implementing restrictive file permissions and monitoring for unauthorized modifications to the fld program and its input processing capabilities. Additionally, the vulnerability underscores the necessity of regular security audits of legacy system components and the importance of applying security patches promptly to prevent exploitation of known vulnerabilities.