CVE-2004-0919 in FreeBSD
Summary
by MITRE
The syscons CONS_SCRSHOT ioctl in FreeBSD 5.x allows local users to read arbitrary kernel memory via (1) negative coordinates or (2) large coordinates.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2004-0919 affects FreeBSD 5.x operating systems and resides within the syscons console driver implementation. This issue manifests through the CONS_SCRSHOT ioctl command which is designed to capture screen shots from the console subsystem. The flaw represents a classic buffer overflow condition that occurs when the system processes coordinate parameters without proper validation, creating an opportunity for privilege escalation and information disclosure.
The technical implementation of this vulnerability stems from inadequate input sanitization within the syscons driver's ioctl handler. When local users provide negative coordinates or coordinates exceeding system limits, the driver fails to validate these inputs properly before using them in memory access operations. This lack of bounds checking allows attackers to manipulate memory access patterns and read kernel memory contents that should remain protected from user-space access. The vulnerability specifically targets the console subsystem's screen capture functionality where coordinate parameters control memory offsets and buffer boundaries.
From an operational perspective, this vulnerability presents a significant security risk to FreeBSD 5.x systems as it enables local users to bypass kernel memory protection mechanisms. The ability to read arbitrary kernel memory can expose sensitive information including cryptographic keys, passwords, system configuration data, and other confidential materials stored in kernel space. Attackers can leverage this information to perform further exploitation or gain deeper system access. The impact is particularly concerning in multi-user environments where local privilege escalation could lead to complete system compromise.
The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and demonstrates characteristics consistent with the ATT&CK technique T1063 for "Security Software Discovery" and T1059 for "Command and Scripting Interpreter." Organizations should implement immediate mitigations including applying the official FreeBSD security patches, disabling unnecessary console functionality, and monitoring for suspicious system calls. System administrators should also consider implementing kernel memory protection features and regular security audits to prevent exploitation of similar vulnerabilities in other subsystems.
This vulnerability highlights the importance of proper input validation in kernel space operations and demonstrates how seemingly benign console functionality can become a vector for serious security breaches. The flaw serves as a reminder of the critical need for comprehensive security testing of kernel modules and the importance of maintaining up-to-date system patches to protect against known vulnerabilities.