CVE-1999-0979 in UnixWare
Summary
by MITRE
The SCO UnixWare privileged process system allows local users to gain root privileges by using a debugger such as gdb to insert traps into _init before the privileged process is executed.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability described in CVE-1999-0979 represents a critical privilege escalation flaw within the SCO UnixWare operating system's privileged process execution mechanism. This weakness specifically targets the system's handling of process initialization and privilege management during the boot sequence, creating an exploitable window where local attackers can manipulate the execution flow of critical system components.
The technical flaw exploits a timing vulnerability in the UnixWare privileged process system where the _init process executes before certain security checks are properly enforced. When a local user employs a debugger such as gdb to insert breakpoints or traps into the _init process, they can intercept and manipulate the execution flow before the system has fully established its privileged state. This creates an opportunity for attackers to execute arbitrary code with root privileges, effectively bypassing the normal access controls that should prevent unauthorized privilege escalation.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it fundamentally undermines the security model of the UnixWare system. Attackers can leverage this weakness to gain complete administrative control over affected systems, potentially leading to data compromise, system corruption, or further lateral movement within network environments. The vulnerability is particularly concerning because it requires minimal privileges to exploit and can be executed by any local user with debugger access, making it a significant threat to system integrity.
This vulnerability aligns with CWE-284, which describes improper access control in software systems, and demonstrates how insufficient privilege checking during process initialization can create persistent security weaknesses. From an ATT&CK perspective, this represents a privilege escalation technique using debugging tools and process manipulation, specifically falling under T1068 for local privilege escalation and T1562 for evasion through process injection. The exploitability of this vulnerability highlights the importance of proper process isolation and privilege management during system initialization phases, as well as the need for robust security controls that prevent unauthorized debugging of critical system processes. Organizations should implement strict access controls on debugging tools and ensure that privileged processes are properly protected against manipulation during their execution lifecycle.
The mitigation strategies for this vulnerability require comprehensive system hardening measures including restricting access to debugging tools, implementing proper process monitoring, and ensuring that privileged processes are protected against manipulation. System administrators should also consider implementing additional security controls such as mandatory access controls and process integrity checking mechanisms to prevent unauthorized modifications to critical system components during the boot process.