CVE-2002-0793 in RTOS
Summary
by MITRE
Hard link and possibly symbolic link following vulnerabilities in QNX RTOS 4.25 (aka QNX4) allow local users to overwrite arbitrary files via (1) the -f argument to the monitor utility, (2) the -d argument to dumper, (3) the -c argument to crttrap, or (4) using the Watcom sample utility.
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Analysis
by VulDB Data Team • 11/28/2024
The vulnerability identified as CVE-2002-0793 represents a critical security flaw in QNX RTOS 4.25 systems that stems from improper handling of file system operations involving hard links and symbolic links. This issue affects multiple system utilities including monitor, dumper, crttrap, and a Watcom sample utility, creating widespread potential for privilege escalation and arbitrary file modification. The vulnerability specifically manifests when these utilities process command line arguments that involve file paths, allowing local attackers to exploit the system through carefully crafted inputs that leverage link following mechanisms.
The technical root cause of this vulnerability lies in the insufficient validation and sanitization of file path arguments within the affected QNX utilities. When these tools process arguments such as -f for monitor, -d for dumper, -c for crttrap, or through the Watcom sample utility, they fail to properly verify the integrity of the file paths they receive. This allows attackers to create hard links or symbolic links that point to sensitive system files, then manipulate these links to overwrite critical files with malicious content. The flaw essentially enables attackers to bypass normal file system access controls by exploiting the underlying link following behavior of the operating system.
From an operational perspective, this vulnerability presents significant risks to embedded systems and real-time computing environments that rely on QNX RTOS 4.25. Local users with minimal privileges can exploit these weaknesses to overwrite arbitrary files, potentially leading to system compromise, data corruption, or denial of service conditions. The impact extends beyond simple file overwrites since attackers can target critical system files, configuration data, or even system executables to gain elevated privileges or disrupt normal operations. This vulnerability particularly affects industrial control systems, automotive applications, and other embedded environments where QNX RTOS is commonly deployed.
The exploitation of these vulnerabilities aligns with several ATT&CK framework techniques including privilege escalation through file system manipulation and persistence mechanisms. From a CWE perspective, this vulnerability maps to CWE-59, which describes improper handling of symbolic links, and CWE-22, which covers improper limitation of a pathname to a restricted directory. These weaknesses collectively enable attackers to perform path traversal attacks that bypass normal security controls. Organizations should implement immediate mitigations including updating to patched versions of QNX RTOS, restricting access to affected utilities, and implementing proper file system access controls. The vulnerability also highlights the importance of secure coding practices in embedded systems where traditional security controls may be insufficient.
Security practitioners should consider the broader implications of this vulnerability within their embedded system environments, as QNX RTOS 4.25 systems often operate in critical infrastructure settings where the potential for cascading failures exists. The lack of proper input validation in these utilities demonstrates a fundamental security gap that requires both immediate remediation and long-term architectural improvements. Organizations maintaining legacy QNX systems should prioritize upgrading to supported versions and implementing comprehensive monitoring for suspicious file system activities that might indicate exploitation attempts.