Source: cve@mitre.org
Vulnerability in prwarn in SCO UNIX 4.2 and earlier allows local users to gain root access.
SCO UNIX 4.2 and earlier systems are vulnerable to a critical local privilege escalation via the prwarn utility. Successful exploitation allows a local user to gain root access, granting complete control over the compromised system and potentially leading to significant data breaches and system compromise. This vulnerability, though old, highlights the importance of patching and maintaining up-to-date security configurations.
Step 1: Input Preparation: The attacker crafts a malicious input string designed to trigger the vulnerability in prwarn. This input could be a specially formatted string or a buffer overflow payload.
Step 2: Payload Injection: The attacker provides the crafted input to the prwarn utility, likely through a file or command-line argument.
Step 3: Vulnerability Trigger: The prwarn utility processes the malicious input, leading to a buffer overflow or other memory corruption. This overwrites critical memory regions.
Step 4: Control Hijack: The attacker's crafted input overwrites the return address or other control data, redirecting program execution to a location controlled by the attacker (e.g., a shellcode).
Step 5: Privilege Escalation: The attacker's shellcode executes with root privileges, granting the attacker complete control over the system.
The vulnerability lies within the prwarn utility, likely due to a buffer overflow or format string vulnerability. The prwarn utility, when executed with crafted input, fails to properly validate or sanitize user-supplied data. This allows an attacker to overwrite critical memory locations, potentially including the return address on the stack. By controlling the return address, the attacker can redirect program execution to malicious code, such as a shell, executed with root privileges. The root cause is a lack of input validation and bounds checking within the prwarn utility, allowing for the injection of malicious code or the overwriting of critical data structures.
Due to the age of the vulnerability, it's unlikely to be associated with specific APT groups in current reports. However, any threat actor with access to vulnerable systems could exploit it. The vulnerability's age and potential for root access make it a prime target for opportunistic attacks. CISA KEV: Not Listed
Monitor system logs for unusual activity related to the prwarn utility, including unexpected command-line arguments or file access.
Analyze system logs for suspicious process creation or execution, particularly those initiated by the prwarn utility.
Implement file integrity monitoring to detect unauthorized modifications to system binaries, including prwarn.
Network traffic analysis may reveal attempts to exploit the vulnerability, although this is less likely for a local privilege escalation. Look for unusual network connections originating from the compromised system after exploitation.
Patch the system to the latest available version or apply security updates provided by SCO (if available).
If patching is not possible, remove or restrict the execution of the prwarn utility. Consider renaming the binary or removing execute permissions.
Implement strong access controls to limit user privileges and prevent unauthorized access to sensitive files and directories.
Regularly audit system configurations and security settings to ensure they are up-to-date and properly configured.
Implement a robust intrusion detection and prevention system (IDS/IPS) to monitor for and block malicious activity.
Conduct regular vulnerability scans to identify and address potential security weaknesses.