CVE-1999-0336 in HP-UX
Summary
by MITRE
buffer overflow in mstm in hp-ux allows local users to gain root access.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability identified as CVE-1999-0336 represents a critical buffer overflow flaw within the mstm component of Hewlett-Packard Unix operating systems. This issue specifically affects HP-UX systems and creates a pathway for local attackers to escalate privileges to the root level. The mstm service, which handles certain system management functions, contains a programming error that allows malicious input to overflow allocated memory buffers, potentially leading to arbitrary code execution with elevated privileges.
The technical nature of this buffer overflow stems from improper input validation within the mstm application's memory handling routines. When the application processes certain input parameters, it fails to properly check buffer boundaries before copying data into fixed-size memory locations. This classic programming flaw enables attackers to overwrite adjacent memory locations, including return addresses and control data, which can be manipulated to redirect program execution flow. The vulnerability is particularly dangerous because it occurs within a system management service that typically runs with elevated privileges, making the potential for privilege escalation substantial.
From an operational perspective, this vulnerability presents a significant risk to HP-UX environments as local users who can execute programs on the system can exploit this flaw to gain root access. The attack vector requires local system access but does not need network connectivity, making it particularly concerning for systems where local access controls are insufficient. Once successfully exploited, the attacker gains complete control over the system, including the ability to modify system files, create new user accounts, and access all stored data. The impact extends beyond individual system compromise to potentially affect entire network infrastructures where HP-UX systems serve critical functions.
The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of how improper memory management can lead to privilege escalation attacks. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where adversaries leverage software flaws to gain elevated system access. Organizations should implement immediate mitigations including applying the relevant HP-UX security patches, disabling unnecessary mstm services where possible, and implementing strict local access controls. System administrators should also consider monitoring for suspicious process execution patterns and ensure that only authorized users have local system access. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar flaws in other system components, as buffer overflow vulnerabilities remain a prevalent class of security issues across operating systems and applications.