Source: cve@mitre.org
Vulnerability in scoterm in SCO OpenServer 5.0 and SCO Open Desktop/Open Server 3.0 allows local users to gain root privileges.
SCO OpenServer and Open Desktop/Open Server systems are vulnerable to a local privilege escalation via a flaw in the scoterm utility, allowing attackers to gain root access. This vulnerability, dating back to the late 1990s, could lead to complete system compromise and data exfiltration. Organizations still running these legacy systems are at significant risk and should prioritize immediate mitigation efforts.
Step 1: Vulnerability Trigger: The attacker interacts with the scoterm utility, typically through a local terminal session or a crafted input file.
Step 2: Malicious Input: The attacker provides a specially crafted input string designed to exploit a memory corruption vulnerability, such as a buffer overflow.
Step 3: Memory Corruption: The malicious input overwrites critical memory regions, potentially including the stack or heap, corrupting program control flow.
Step 4: Control Hijack: The attacker's crafted input overwrites the return address, redirecting program execution to attacker-controlled code (e.g., a shellcode).
Step 5: Privilege Escalation: The attacker's shellcode executes with the privileges of the scoterm process, which is typically root, granting the attacker root access to the system.
The vulnerability lies within the scoterm utility, likely due to a buffer overflow or similar memory corruption issue. The scoterm program, when running with elevated privileges (e.g., setuid root), likely fails to properly validate user-supplied input. This allows an attacker to craft a malicious input that overwrites critical memory regions, potentially including the return address on the stack. By controlling the return address, the attacker can redirect program execution to arbitrary code, such as a shell, executed with root privileges. The root cause is a lack of input validation and/or improper bounds checking when handling user-provided data within the scoterm application.
Due to the age of the vulnerability, it is unlikely to be actively targeted by sophisticated APT groups. However, it is a prime target for opportunistic attackers and script kiddies. The vulnerability is not listed on the CISA KEV catalog, likely due to the age and limited modern usage of the affected systems.
Monitor system logs for suspicious activity related to scoterm. Look for unusual command executions or unexpected errors.
Analyze process execution history for instances of scoterm being run with elevated privileges.
Examine core dumps or crash reports for evidence of memory corruption or stack overflows.
Network traffic analysis may reveal attempts to interact with the vulnerable service, though this is less likely in a local privilege escalation scenario.
The primary remediation is to immediately upgrade to a supported operating system. SCO OpenServer 5.0 and SCO Open Desktop/Open Server 3.0 are severely outdated and no longer receive security updates.
If upgrading is not immediately possible, isolate the affected systems from the network to limit exposure.
Remove or disable the scoterm utility if it is not essential for system operation.
Implement strict access controls to limit user access to the affected systems.
Conduct a thorough security audit of the affected systems to identify other potential vulnerabilities.
Implement intrusion detection and prevention systems (IDS/IPS) to monitor for and block malicious activity.