CVE-2000-1043 in Mandrake Linux
Summary
by MITRE
Format string vulnerability in ypserv in Mandrake Linux 7.1 and earlier, and possibly other Linux operating systems, allows an attacker to gain root privileges when ypserv is built without a vsyslog() function.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 06/25/2021
The vulnerability identified as CVE-2000-1043 represents a critical format string flaw within the ypserv daemon, which serves as the NIS (Network Information Service) server component in Unix-like operating systems. This issue specifically affects Mandrake Linux 7.1 and earlier versions, though it may potentially impact other Linux distributions where the ypserv implementation lacks proper vsyslog() function handling. The vulnerability stems from improper input validation and string formatting operations within the daemon's logging mechanisms, creating a pathway for privilege escalation attacks.
The technical flaw manifests when ypserv processes user-supplied data through format string functions without adequate sanitization. When the daemon is compiled without the vsyslog() function, it falls back to using standard printf-style functions that are susceptible to format string exploitation. Attackers can craft malicious input that includes format specifiers such as %x, %s, or %n, which when processed by the vulnerable logging functions can lead to arbitrary memory reads, writes, or even code execution. The absence of vsyslog() creates a specific code path where the daemon's logging behavior becomes exploitable, as the standard logging functions do not properly handle format string arguments from untrusted sources.
The operational impact of this vulnerability is severe, as successful exploitation allows remote attackers to achieve root privileges on affected systems. This privilege escalation occurs because ypserv typically runs with elevated permissions to manage network information services, and the format string vulnerability provides a means to bypass normal access controls. Once root access is obtained, attackers can modify system files, install backdoors, establish persistent access, and compromise the entire system. The vulnerability is particularly dangerous in networked environments where NIS services are actively used for centralized system management, as it can be exploited without requiring prior authentication or local access to the system.
Mitigation strategies for CVE-2000-1043 involve multiple layers of defensive measures. System administrators should immediately upgrade to patched versions of Mandrake Linux or apply vendor-specific security patches that address the format string vulnerability. The recommended approach includes ensuring that ypserv is compiled with proper vsyslog() function support or implementing input validation mechanisms that prevent format string exploitation. Additionally, network segmentation should be implemented to restrict access to NIS services, and the daemon should be run with minimal privileges where possible. Security monitoring should be enhanced to detect unusual logging patterns or attempts to exploit format string vulnerabilities. This vulnerability aligns with CWE-134 which specifically addresses format string vulnerabilities, and falls under ATT&CK technique T1068 for privilege escalation through local exploits. Organizations should also consider implementing network intrusion detection systems to monitor for exploitation attempts targeting this specific vulnerability class.