CVE-2000-0794 in IRIX
Summary
by MITRE
Buffer overflow in IRIX libgl.so library allows local users to gain root privileges via a long HOME variable to programs such as (1) gmemusage and (2) gr_osview.
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Analysis
by VulDB Data Team • 10/15/2024
The vulnerability described in CVE-2000-0794 represents a critical buffer overflow flaw within the IRIX operating system's libgl.so library that enables local attackers to escalate their privileges to root level. This issue specifically affects programs that utilize the Graphics Library (libgl) functionality, namely gmemusage and gr_osview utilities. The vulnerability stems from improper input validation when processing the HOME environment variable, creating a condition where a maliciously crafted long HOME variable can overwrite adjacent memory locations in the program's stack space. The flaw exists at the system level within the graphics library implementation, making it particularly dangerous as it can be exploited by any local user who has access to execute these specific programs.
The technical implementation of this buffer overflow occurs when the gmemusage and gr_osview programs process the HOME environment variable without adequate bounds checking. The libgl.so library fails to validate the length of the HOME variable before copying it into a fixed-size buffer, allowing an attacker to exceed the allocated memory space and overwrite critical program data including return addresses and saved registers. This memory corruption directly enables arbitrary code execution with the privileges of the target program, which typically runs with elevated permissions. The vulnerability specifically maps to CWE-121, which describes stack-based buffer overflow conditions, and aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' through local system exploits. The attack vector is local and requires the victim to execute one of the vulnerable programs with elevated privileges, making it particularly effective in scenarios where users might run these tools with root access or where they are setuid binaries.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can be leveraged to establish persistent access to affected systems running IRIX. Once successfully exploited, attackers can execute arbitrary commands with root privileges, potentially leading to complete system compromise and data exfiltration. The vulnerability affects systems running IRIX operating systems and is particularly concerning because it requires minimal user interaction beyond executing the vulnerable programs, making it a low-effort, high-impact attack vector. The exploitation process typically involves crafting a specially formatted HOME environment variable that, when processed by the vulnerable programs, triggers the buffer overflow condition and allows the attacker to inject and execute malicious code. Organizations with IRIX systems should consider this vulnerability as a critical threat requiring immediate remediation, as it provides a straightforward path to system compromise.
The recommended mitigation strategies for CVE-2000-0794 include immediate patching of the affected IRIX systems through official vendor updates, which would address the buffer overflow in the libgl.so library. System administrators should also implement proper input validation for environment variables and consider restricting execution of vulnerable programs to trusted users only. Additionally, monitoring for suspicious environment variable usage and implementing privilege separation techniques can help reduce the attack surface. The vulnerability highlights the importance of secure coding practices, particularly around buffer management and input validation, and demonstrates how seemingly innocuous environment variable handling can create significant security risks. Organizations should also review their system configurations to ensure that vulnerable programs are not running with unnecessary elevated privileges and that proper access controls are in place to limit potential exploitation opportunities.