CVE-2001-0779 in HP-UX
Summary
by MITRE
Buffer overflow in rpc.yppasswdd (yppasswd server) in Solaris 2.6, 7 and 8 allows remote attackers to gain root access via a long username.
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Analysis
by VulDB Data Team • 10/04/2025
The vulnerability identified as CVE-2001-0779 represents a critical buffer overflow flaw within the yppasswd server component of Solaris operating systems version 2.6, 7, and 8. This issue specifically affects the rpc.yppasswdd daemon which handles password changes across NIS (Network Information Service) domains. The vulnerability stems from inadequate input validation in the username parameter processing, creating a condition where maliciously crafted input can overwrite adjacent memory locations beyond the allocated buffer boundaries. The affected system components operate with elevated privileges as part of the Network Information Service infrastructure, making this vulnerability particularly dangerous for attackers seeking unauthorized system access.
This buffer overflow vulnerability manifests when an attacker sends a specially crafted username string that exceeds the predetermined buffer size allocated for username processing within the yppasswd server. The excessive input causes memory corruption that can be exploited to overwrite critical program variables, return addresses, or other control data structures. The flaw operates at the application layer and leverages the inherent trust relationships within NIS environments where rpc.yppasswdd typically runs with root privileges. According to CWE classification, this corresponds to CWE-121, which describes heap-based buffer overflow conditions, and CWE-787, which covers out-of-bounds write vulnerabilities. The attack vector requires network connectivity to the target system and can be executed remotely without authentication, making it particularly attractive to threat actors seeking system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with complete control over affected systems. Successful exploitation can result in unauthorized root access, allowing adversaries to modify system files, install backdoors, exfiltrate sensitive data, or establish persistent access points within the network. The vulnerability affects enterprise environments that rely on NIS for user authentication and management, potentially compromising entire domains if multiple systems are vulnerable. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1068, which covers exploit for privilege escalation, and T1566, which involves spearphishing with a malicious attachment or link. The exploitation process typically involves crafting a payload that overflows the username buffer and redirects program execution flow to malicious code.
Mitigation strategies for CVE-2001-0779 require immediate system hardening measures including applying vendor security patches, disabling unnecessary NIS services, and implementing network segmentation to limit exposure. System administrators should disable the yppasswd service entirely if not required for operations, as this eliminates the attack surface entirely. Network-level protections such as firewall rules can restrict access to NIS ports to trusted networks only, while monitoring solutions should be deployed to detect anomalous authentication patterns. The recommended remediation approach includes upgrading to patched versions of Solaris, implementing input validation controls within application code, and conducting thorough vulnerability assessments of NIS infrastructure components. Additionally, organizations should consider migrating from legacy NIS systems to more secure modern authentication frameworks such as LDAP or Kerberos to reduce dependency on vulnerable legacy services and improve overall security posture.