CVE-2002-0836 in Secure OS
Summary
by MITRE
dvips converter for Postscript files in the tetex package calls the system() function insecurely, which allows remote attackers to execute arbitrary commands via certain print jobs, possibly involving fonts.
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Analysis
by VulDB Data Team • 09/13/2025
The vulnerability described in CVE-2002-0836 represents a critical security flaw within the tetex package's dvips converter component that processes postscript files. This converter serves as a bridge between postscript documents and printer output, making it a crucial element in document processing workflows. The vulnerability specifically targets the insecure handling of system calls within the dvips utility, creating a pathway for malicious actors to execute unauthorized commands on systems where the affected software is installed. This flaw exists at the intersection of document processing and system command execution, making it particularly dangerous in environments where print jobs are processed with elevated privileges.
The technical implementation of this vulnerability stems from the dvips converter's improper use of the system() function, which is a standard C library function that executes shell commands. When processing certain print jobs that involve fonts, the dvips utility fails to properly sanitize or validate input parameters before passing them to the system() function. This insecure coding practice allows attackers to inject malicious commands that get executed with the privileges of the user running the dvips process. The vulnerability is particularly concerning because it can be triggered through the normal document processing workflow, making it difficult to detect and prevent. According to CWE classification, this represents a CWE-78: Improper Neutralization of Special Elements used in an OS Command, which specifically addresses the risk of command injection when user-supplied data is incorporated into system commands without proper sanitization.
The operational impact of this vulnerability extends beyond simple command execution, as it can lead to complete system compromise when attackers leverage the elevated privileges associated with print processing. In enterprise environments where print servers handle numerous document processing tasks, this vulnerability could enable attackers to gain unauthorized access to sensitive data, install backdoors, or escalate privileges to administrative levels. The attack vector involves sending specially crafted postscript files or font configurations through the print queue, which then get processed by the vulnerable dvips converter. This scenario aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, specifically focusing on the execution of system commands through legitimate interfaces. The vulnerability also relates to T1068 for Exploitation for Privilege Escalation, as attackers can potentially leverage the elevated privileges of print processing services to gain broader system access.
Mitigation strategies for this vulnerability require immediate patching of the tetex package to address the insecure system() function usage. System administrators should implement input validation and sanitization measures to prevent malicious data from being passed to system commands. Network segmentation and privilege separation can help limit the potential impact if exploitation occurs, ensuring that print processing services run with minimal required privileges. Additionally, monitoring print job processing logs for unusual command executions can help detect exploitation attempts. Organizations should also consider implementing application whitelisting policies to restrict which applications can execute system commands, and regularly review and update security configurations for print servers. The vulnerability highlights the importance of secure coding practices and proper input validation, particularly when dealing with system-level functions that can execute arbitrary code. Regular security assessments and vulnerability scanning should be conducted to identify similar insecure coding patterns in other system components, as this type of vulnerability is often present in legacy software that has not been updated to follow modern security standards.