CVE-2000-0917 in LPRng
Summary
by MITRE
Format string vulnerability in use_syslog() function in LPRng 3.6.24 allows remote attackers to execute arbitrary commands.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2000-0917 represents a critical format string flaw within the LPRng print server software version 3.6.24. This issue specifically affects the use_syslog() function which handles logging operations for print jobs and system messages. The flaw arises when the application processes user-supplied input without proper validation or sanitization before using it in format string operations. Attackers can exploit this weakness by crafting malicious input that contains format specifiers such as %s, %d, or %x which are then interpreted by the vulnerable function during logging operations. This particular vulnerability falls under the CWE-134 category which specifically addresses the use of format strings without proper validation, making it a well-documented and dangerous class of vulnerability.
The operational impact of this vulnerability extends beyond simple privilege escalation to full system compromise. When remote attackers successfully exploit the format string vulnerability in the use_syslog() function, they can execute arbitrary code with the privileges of the LPRng service account. This typically translates to root or administrative privileges on the affected system, allowing attackers to gain complete control over the print server. The vulnerability is particularly concerning because it enables attackers to execute commands directly on the target system without requiring authentication for the print service itself, making it an attractive target for remote exploitation. The attack vector leverages network-based communication with the LPRng service, which often runs on standard ports and may be exposed to external networks.
The exploitation of CVE-2000-0917 aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to command execution and privilege escalation. The vulnerability maps to ATT&CK technique T1059 which covers command and scripting interpreter usage, and T1068 which addresses exploit for privilege escalation. Organizations running LPRng 3.6.24 are at significant risk of lateral movement through compromised print servers, as these systems often serve as entry points into larger network infrastructures. The vulnerability's persistence is enhanced by the fact that LPRng services typically run continuously and may not be properly monitored for unusual activity patterns that could indicate exploitation attempts.
Mitigation strategies for this vulnerability require immediate patching of the LPRng software to version 3.6.25 or later which contains the necessary fixes for the format string handling. System administrators should implement network segmentation to limit access to print server services and disable unnecessary print services where possible. Additional protective measures include implementing proper input validation for all user-supplied data, monitoring syslog entries for suspicious format string patterns, and deploying intrusion detection systems that can identify exploitation attempts. The vulnerability also highlights the importance of maintaining up-to-date software inventory and regular vulnerability assessments, as many organizations may not be aware of running vulnerable versions of legacy software. Security teams should also consider implementing application whitelisting policies to prevent unauthorized execution of vulnerable applications and establish proper network access controls to limit exposure of print services to untrusted networks.