CVE-2000-1123 in AIX
Summary
by MITRE
Buffer overflow in pioout command in IBM AIX 4.3.x and earlier may allow local users to execute arbitrary commands.
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Analysis
by VulDB Data Team • 04/11/2019
The vulnerability identified as CVE-2000-1123 represents a critical buffer overflow flaw within the pioout command of IBM AIX operating systems version 4.3.x and earlier. This command, which is part of the AIX system utilities, handles printer output operations and suffers from improper input validation that allows attackers to exploit memory corruption vulnerabilities. The flaw specifically manifests when the command processes user-supplied input without adequate bounds checking, creating opportunities for malicious code injection through buffer overflow exploitation. This vulnerability exists at the kernel level within the AIX operating system, making it particularly dangerous for local attackers who already possess system access.
The technical implementation of this buffer overflow stems from insufficient boundary checking in the pioout command's memory allocation routines. When processing printer output data, the command allocates fixed-size buffers that do not adequately validate the length of incoming data. This allows attackers to overwrite adjacent memory locations, potentially corrupting program execution flow and enabling arbitrary code execution. The vulnerability is classified as a classic stack-based buffer overflow according to CWE-121, which directly maps to the underlying memory corruption mechanism. The flaw operates under the principle of memory corruption that enables privilege escalation and arbitrary code execution, aligning with ATT&CK technique T1068 for bypassing system protections.
From an operational perspective, this vulnerability poses significant risks to AIX systems running affected versions as it allows local users to gain elevated privileges and execute malicious code with system-level access. The attack vector requires local system access, but once exploited, the consequences extend beyond simple privilege escalation to include potential system compromise and data exfiltration. The vulnerability's impact is particularly severe because it can be exploited by users who already have legitimate access to the system, making detection more challenging. The exploitability factor is high due to the predictable nature of the buffer overflow and the availability of the vulnerable command in standard system utilities, creating a scenario where unauthorized code execution becomes possible through routine system operations.
Mitigation strategies for CVE-2000-1123 involve immediate patching of affected IBM AIX systems with the vendor-provided security updates that address the buffer overflow vulnerability in the pioout command. Organizations should implement comprehensive system hardening measures including disabling unnecessary system utilities and restricting local user privileges to minimize attack surface. System administrators should conduct thorough vulnerability assessments to identify all instances of the vulnerable command and ensure proper input validation mechanisms are in place. Additionally, implementing intrusion detection systems and monitoring for unusual system behavior can help detect exploitation attempts. The remediation process should also include regular security updates and adherence to security best practices as outlined in industry standards such as those provided by NIST and ISO 27001 for system security management.