CVE-2000-0078 in HP-UX
Summary
by MITRE
The June 1999 version of the HP-UX aserver program allows local users to gain privileges by specifying an alternate PATH which aserver uses to find the awk command.
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Analysis
by VulDB Data Team • 06/23/2021
The vulnerability described in CVE-2000-0078 represents a classic privilege escalation flaw in the HP-UX operating system's aserver program from June 1999. This issue stems from improper handling of the PATH environment variable during command execution, creating a security weakness that local attackers can exploit to elevate their privileges. The vulnerability specifically affects the aserver utility which is designed to handle server-side operations within the HP-UX environment. When aserver executes commands, it relies on the system PATH variable to locate executable programs, including the awk utility which is commonly used for text processing and data manipulation tasks.
The technical root cause of this vulnerability aligns with CWE-426, which describes the weakness of an application executing a command that is not properly validated or sanitized. The aserver program fails to properly validate or sanitize the PATH environment variable before using it to locate and execute the awk command. This flaw allows attackers to manipulate the execution environment by placing a malicious version of awk in a directory that appears earlier in the PATH than the legitimate system location. When aserver attempts to execute awk, it inadvertently runs the attacker-controlled version instead of the system-proper awk binary, potentially executing malicious code with elevated privileges.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with a mechanism to gain unauthorized access to system resources and potentially compromise the entire HP-UX system. The vulnerability is particularly concerning because it requires only local access to exploit, making it accessible to users who already have a presence on the system. This local privilege escalation vector can be leveraged to gain root privileges, which would allow attackers to modify system files, install backdoors, or perform other malicious activities that could compromise the integrity and confidentiality of the entire system. The attack surface is further expanded because the aserver program is likely a legitimate system utility that would be expected to run with elevated privileges.
From a cybersecurity perspective, this vulnerability demonstrates the importance of proper input validation and environment variable handling in system utilities. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under privilege escalation tactics, specifically targeting the execution of malicious code through compromised system utilities. Organizations should implement proper PATH validation mechanisms and ensure that system utilities do not rely on potentially manipulated environment variables for command execution. The fix typically involves either hardcoding the full path to system utilities or implementing proper validation of the PATH environment variable before command execution. This vulnerability also underscores the necessity of regular security updates and patch management, as the June 1999 version of HP-UX would have been vulnerable to such attacks due to the lack of proper security hardening in the aserver implementation. System administrators should ensure that all HP-UX systems are updated to versions that address this specific vulnerability and implement monitoring for unauthorized PATH modifications that could indicate exploitation attempts.