CVE-2000-0099 in UnixWare
Summary
by MITRE
Buffer overflow in UnixWare ppptalk command allows local users to gain privileges via a long prompt argument.
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Analysis
by VulDB Data Team • 04/20/2026
The vulnerability identified as CVE-2000-0099 represents a critical buffer overflow flaw within the UnixWare operating system's ppptalk command implementation. This issue manifests as a classic stack-based buffer overflow that occurs when processing user-supplied prompt arguments, creating a pathway for local privilege escalation attacks. The ppptalk command, designed for communication purposes within the UnixWare environment, fails to properly validate the length of input parameters, particularly the prompt argument, allowing malicious actors to overwrite adjacent memory locations on the stack.
The technical exploitation of this vulnerability leverages the fundamental principle of buffer overflow attacks where insufficient input validation permits an attacker to supply more data than the allocated buffer space can accommodate. When the ppptalk command processes a sufficiently long prompt argument, the excess data overflows into adjacent memory regions, potentially corrupting the stack frame and overwriting critical control information such as return addresses or saved registers. This memory corruption can be manipulated to redirect program execution flow and execute arbitrary code with elevated privileges, typically escalating from the current user context to root or administrative privileges.
From an operational impact perspective, this vulnerability presents a significant risk to UnixWare systems as it requires only local access to exploit, eliminating the need for network connectivity or remote attack vectors. Local users who can execute the ppptalk command can leverage this flaw to bypass normal access controls and gain unauthorized administrative privileges. The implications extend beyond immediate privilege escalation, as successful exploitation could enable attackers to modify system files, install backdoors, or establish persistent access to compromised systems. This vulnerability particularly affects environments where local user access is not strictly controlled or where users may have legitimate reasons to execute ppptalk but could potentially abuse the command for malicious purposes.
The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and demonstrates characteristics consistent with attack patterns documented in the MITRE ATT&CK framework under privilege escalation techniques. Specifically, this issue maps to T1068, which covers 'Exploitation for Privilege Escalation', and T1548.001, covering 'Abuse Elevation Control Mechanism'. Organizations should implement immediate mitigations including applying vendor patches, restricting local access to the ppptalk command, and implementing proper input validation mechanisms. System administrators should also consider disabling unnecessary commands, implementing privilege separation, and conducting regular security audits to identify similar vulnerabilities in other system components. The incident highlights the critical importance of proper input validation and memory management practices in system security, particularly for commands that handle user-provided data within privileged contexts.