CVE-2000-0606 in KON
Summary
by MITRE
Buffer overflow in kon program in Kanji on Console (KON) package on Linux may allow local users to gain root privileges via a long -StartupMessage parameter.
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Analysis
by VulDB Data Team • 04/13/2017
The vulnerability described in CVE-2000-0606 represents a classic buffer overflow flaw within the kon program of the Kanji on Console KON package running on Linux systems. This particular implementation flaw exists in the handling of command-line arguments, specifically the -StartupMessage parameter which is processed without adequate bounds checking. The vulnerability arises from insufficient input validation mechanisms that fail to properly constrain the length of user-supplied data before it is copied into fixed-length buffers within the program's memory space. When a local user provides an excessively long argument to the -StartupMessage parameter, the program's memory layout becomes corrupted as the input overflows into adjacent memory regions, potentially overwriting critical program variables or return addresses.
The technical exploitation of this vulnerability leverages the fundamental principles of buffer overflow attacks as outlined in CWE-121, which describes the condition where a program writes data to a buffer that is insufficient to hold the data being written. The kon program's failure to implement proper bounds checking creates an opportunity for malicious input to overwrite the stack frame, potentially allowing an attacker to manipulate the program's execution flow. This particular vulnerability is classified as a local privilege escalation issue since it enables a user with minimal privileges to execute arbitrary code with root privileges. The attack vector is particularly concerning because it requires only local access to the system and can be executed through the command-line interface of the vulnerable application.
From an operational perspective, this vulnerability poses significant risks to Linux systems that utilize the KON package for kanji character set handling in console environments. The impact extends beyond simple denial of service as the privilege escalation capability allows attackers to gain full administrative control over affected systems. This vulnerability is particularly dangerous in multi-user environments where local access might be more readily available than remote access. The exploitation process typically involves crafting a specially formatted -StartupMessage parameter that exceeds the allocated buffer size, causing the stack to be overwritten in such a way that the program's execution flow can be redirected to malicious code. This attack pattern aligns with techniques described in the ATT&CK framework under the privilege escalation tactic, specifically targeting local execution and memory corruption methods.
The remediation of this vulnerability requires immediate patching of the KON package to implement proper input validation and bounds checking for all command-line parameters. System administrators should ensure that the vulnerable software is either updated to a patched version or completely removed from production environments. Additionally, implementing proper input sanitization measures including length validation, buffer overflow protection mechanisms, and stack canary implementations would significantly reduce the risk of exploitation. Organizations should also consider implementing monitoring solutions to detect unusual command-line argument patterns that might indicate attempted exploitation of similar buffer overflow vulnerabilities. The vulnerability serves as a reminder of the critical importance of secure coding practices and the necessity of thorough input validation in all system components, particularly those that process user-supplied data in privileged contexts.