Source: cve@mitre.org
Buffer overflow in Solaris x86 mkcookie allows local users to obtain root access.
Solaris x86 systems are vulnerable to a critical buffer overflow in the mkcookie utility, allowing local attackers to gain root privileges. Successful exploitation grants complete control over the compromised system, potentially leading to data breaches and system compromise.
Step 1: Triggering the Vulnerability: The attacker executes the mkcookie utility with a specially crafted input. This input is designed to be larger than the allocated buffer within the program.
Step 2: Buffer Overflow: The oversized input overwrites the allocated buffer and spills into adjacent memory regions, including the stack.
Step 3: Overwriting the Return Address: The overflow corrupts the return address stored on the stack. The return address dictates where the program should resume execution after the current function completes.
Step 4: Injecting Shellcode: The attacker's crafted input includes malicious code (shellcode) designed to execute commands with elevated privileges. This shellcode is placed within the overflowed buffer.
Step 5: Gaining Root Access: The overwritten return address is set to point to the attacker's shellcode. When the vulnerable function returns, it jumps to the shellcode, which then executes with root privileges, granting the attacker complete control of the system.
The vulnerability lies within the mkcookie utility on Solaris x86 systems. Specifically, the mkcookie program fails to properly validate the size of input data, leading to a buffer overflow. The program likely allocates a fixed-size buffer to store data, and when a crafted input exceeding this buffer size is provided, it overwrites adjacent memory regions. This overwrite can corrupt critical program data, including the return address on the stack. By carefully crafting the input, an attacker can overwrite the return address with the address of malicious code (e.g., a shellcode) injected into the buffer, thus gaining control of the program's execution flow. The program then executes the attacker's shellcode with the privileges of the user running mkcookie, which, in this case, is often root.
While specific APT groups may not be directly tied to this specific CVE, the ease of exploitation and the potential for complete system compromise make it a target for a wide range of threat actors. This vulnerability is a common component in many exploit kits and is often used as a stepping stone to further compromise. This CVE is not listed in the CISA KEV (Known Exploited Vulnerabilities) catalog, but its age and ease of exploitation make it a high-risk vulnerability.
Monitor system logs for suspicious activity related to the execution of mkcookie. Look for unusual command-line arguments or repeated attempts to execute the utility.
Analyze system logs for signs of privilege escalation, such as unexpected changes to user accounts or file permissions.
Implement file integrity monitoring to detect unauthorized modifications to system binaries, including mkcookie.
Network traffic analysis: While this is a local exploit, unusual network activity originating from the compromised host after the exploit could indicate post-exploitation activity (e.g., data exfiltration, command and control communication).
Examine core dumps or memory dumps for evidence of buffer overflows and shellcode injection. Look for unusual stack behavior.
Apply the vendor-provided patch immediately. This is the most effective solution.
If patching is not immediately possible, restrict access to the mkcookie utility. Consider removing the setuid bit if it's not essential for functionality.
Implement a robust intrusion detection and prevention system (IDPS) to monitor for and block exploit attempts.
Regularly audit system configurations and user accounts to identify and mitigate potential security risks.
Implement least privilege principles, limiting the privileges of user accounts to the minimum necessary for their tasks.
Consider using a host-based intrusion detection system (HIDS) to monitor for suspicious activity on the system.