CVE-2001-1529 in AIX
Summary
by MITRE
Buffer overflow in rpc.yppasswdd (yppasswd server) in AIX allows attackers to gain unauthorized access via a long string. NOTE: due to lack of details in the vendor advisory, it is not clear if this is the same issue as CVE-2001-0779.
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Analysis
by VulDB Data Team • 06/27/2021
The vulnerability identified as CVE-2001-1529 represents a critical buffer overflow condition within the rpc.yppasswdd component of IBM AIX operating systems, specifically affecting the NIS (Network Information Service) yppasswd server functionality. This buffer overflow occurs when the server processes user input through the yppasswd protocol, which is designed to allow remote users to update their passwords across networked systems. The flaw manifests when an attacker submits an excessively long string to the yppasswdd service, causing memory corruption that can potentially be exploited to execute arbitrary code with elevated privileges. The vulnerability resides in the server-side implementation of the yppasswd protocol, making it particularly dangerous in environments where NIS services are actively utilized for user authentication and password management.
The technical implementation of this buffer overflow stems from inadequate input validation within the rpc.yppasswdd daemon, which fails to properly bounds-check user-supplied strings before copying them into fixed-size memory buffers. According to CWE-121, this vulnerability maps directly to a classic stack-based buffer overflow condition where insufficient boundary checks allow attackers to overwrite adjacent memory locations. The flaw creates a potential execution path where malicious input can overwrite return addresses, function pointers, or other critical control data structures within the program's memory space. The yppasswd protocol, which operates over RPC (Remote Procedure Call), provides a legitimate interface for password updates but becomes exploitable when the server fails to validate the length of incoming data streams. This vulnerability directly relates to the ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and specifically addresses how buffer overflows can be leveraged to gain elevated system privileges.
The operational impact of CVE-2001-1529 extends beyond simple unauthorized access, as successful exploitation can result in complete system compromise and privilege escalation within affected AIX environments. Attackers who successfully exploit this vulnerability can potentially execute arbitrary code with the privileges of the rpc.yppasswdd process, which typically runs with root-level permissions due to its role in managing system authentication data. The implications are particularly severe in enterprise environments where AIX systems serve as critical infrastructure components and where NIS services are commonly deployed for centralized user management. The vulnerability affects multiple AIX versions and can be exploited remotely without requiring authentication, making it a significant threat to network security. Organizations utilizing AIX systems with active NIS services face potential data breaches, system compromise, and unauthorized access to sensitive user credentials and authentication information.
Mitigation strategies for this vulnerability should include immediate application of vendor security patches and updates provided by IBM, as well as implementing network-level restrictions to limit access to the yppasswd service. System administrators should disable unnecessary NIS services and consider implementing network segmentation to prevent unauthorized access to systems running affected versions of rpc.yppasswdd. The implementation of proper input validation mechanisms and bounds checking within the application code represents a fundamental defensive measure against similar buffer overflow conditions. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems running affected AIX versions and ensure that the yppasswd service is either patched or appropriately restricted. Monitoring for suspicious network traffic patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how legacy authentication services can present significant security risks when not properly maintained or secured against known exploitation techniques.