CVE-2000-1189 in Linux
Summary
by MITRE
Buffer overflow in pam_localuser PAM module in Red Hat Linux 7.x and 6.x allows attackers to gain privileges.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/14/2019
The vulnerability identified as CVE-2000-1189 represents a critical buffer overflow flaw within the pam_localuser Pluggable Authentication Module (PAM) component of Red Hat Linux versions 6.x and 7.x. This issue resides in the authentication framework that governs user access control and credential verification processes. The buffer overflow occurs when the pam_localuser module processes user input without proper bounds checking, creating an exploitable condition that can be leveraged by malicious actors to execute arbitrary code with elevated privileges. The vulnerability specifically affects systems where PAM is configured to use the pam_localuser module for authentication decisions, making it particularly dangerous in enterprise environments where authentication security is paramount.
The technical implementation of this buffer overflow stems from inadequate input validation within the pam_localuser module's handling of user identifiers and authentication parameters. When a user attempts authentication, the module processes the provided username or identifier and stores it in a fixed-size buffer without sufficient bounds checking. This allows an attacker to craft specially formatted input that exceeds the buffer capacity, causing memory corruption that can overwrite adjacent memory locations including return addresses and control data. The flaw directly maps to CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking permits data to overwrite adjacent memory regions. The vulnerability is particularly concerning because it operates at the authentication layer where successful exploitation can result in complete system compromise and privilege escalation.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential complete system compromise and unauthorized access to sensitive data. Attackers exploiting this buffer overflow can gain root-level privileges, enabling them to modify system files, install backdoors, and establish persistent access to the compromised system. The vulnerability affects the core authentication infrastructure of Red Hat Linux systems, potentially allowing attackers to bypass authentication mechanisms entirely or manipulate user access controls. Organizations running affected versions of Red Hat Linux face significant risk of unauthorized system access, data breaches, and potential lateral movement within their network infrastructure. This vulnerability also demonstrates the critical importance of maintaining up-to-date security patches in authentication systems, as the attack surface extends to all services relying on PAM for authentication validation.
Mitigation strategies for CVE-2000-1189 require immediate patching of affected Red Hat Linux systems with the vendor-provided security updates. System administrators should also implement additional security controls including disabling unnecessary authentication modules, implementing proper input validation mechanisms, and monitoring authentication logs for suspicious activity. Network segmentation and access controls can help limit the potential impact of successful exploitation attempts. The vulnerability aligns with ATT&CK technique T1548.001 which covers privilege escalation through authentication component manipulation, emphasizing the need for comprehensive authentication security measures. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures for handling potential security breaches. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in other authentication components and system services.