CVE-2000-1042 in Mandrake Linux
Summary
by MITRE
Buffer overflow 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.
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Analysis
by VulDB Data Team • 06/25/2021
The vulnerability identified as CVE-2000-1042 represents a critical buffer overflow flaw within the ypserv daemon, which is part of the NIS (Network Information Service) implementation commonly found in Linux systems. This issue specifically affects Mandrake Linux 7.1 and earlier versions, though it may potentially impact other Linux distributions as well. The ypserv service is responsible for maintaining and distributing network-wide information such as user accounts, group memberships, and other system configuration data across networked systems. When ypserv is compiled without the vsyslog() function, it becomes susceptible to exploitation through malformed input data that can overwrite adjacent memory regions. This particular configuration flaw creates a pathway for attackers to execute arbitrary code with elevated privileges.
The technical nature of this vulnerability stems from improper input validation within the ypserv daemon's handling of network requests. When the vsyslog() function is absent from the compiled binary, the daemon relies on alternative logging mechanisms that do not properly bounds-check input data before processing. This allows an attacker to craft malicious input that exceeds the allocated buffer space, causing a buffer overflow condition. The overflow occurs in the logging function where the daemon writes information to system logs, and since the vsyslog() function is not present, the alternative implementation lacks proper safeguards against excessive input. The vulnerability is particularly dangerous because it enables privilege escalation from a regular user to root access, as the ypserv daemon typically runs with elevated privileges to perform its network service functions.
The operational impact of this vulnerability extends beyond simple system compromise, as it can lead to complete system takeover and persistent access within networked environments. Attackers exploiting this vulnerability can gain root privileges without requiring authentication, making it a severe threat to network security. Once compromised, the affected system can be used as a pivot point for further attacks within the network, potentially enabling lateral movement and data exfiltration. The vulnerability affects systems where NIS services are actively running and configured, which is common in enterprise environments where centralized user management is required. Organizations with multiple systems relying on NIS for authentication and configuration management face significant risk when this vulnerability exists in their infrastructure, as a single compromised system can potentially provide access to the entire network.
Mitigation strategies for this vulnerability require immediate action to address the underlying buffer overflow condition. The primary recommendation involves updating to patched versions of Mandrake Linux or applying the appropriate security patches that ensure proper bounds-checking in the ypserv implementation. System administrators should also verify that the ypserv daemon is built with the vsyslog() function present, as this prevents the vulnerable code path from being executed. Network segmentation and firewall rules should be implemented to restrict access to NIS services to only authorized systems, reducing the attack surface. Additionally, monitoring for suspicious network traffic patterns and anomalous logging activity can help detect exploitation attempts. From a compliance perspective, this vulnerability aligns with CWE-121, which covers stack-based buffer overflow conditions, and represents a critical weakness in the system's input validation mechanisms. The ATT&CK framework categorizes this as a privilege escalation technique, specifically leveraging weaknesses in system services and daemon implementations to achieve elevated access. Organizations should also consider implementing network intrusion detection systems and regular security assessments to identify similar vulnerabilities in other system components that might provide similar attack vectors for privilege escalation.