PInfo 0.6.9-5.1 Local Buffer Overflow Vulnerability

PInfo 0.6.9-5.1 contains a critical local buffer overflow vulnerability (CVE-2016-20044) that allows a malicious local attacker to execute arbitrary code. This vulnerability stems from the application’s insufficient input validation when handling the ‘-m’ parameter. By exploiting this flaw, an attacker can overwrite the instruction pointer and gain unauthorized access. This can potentially lead to full system compromise. The attacker crafts a malicious input string with 564 bytes of padding followed by a return address.

Attack Chain

1. The attacker gains local access to the vulnerable system.
2. The attacker identifies the PInfo binary (likely located in /usr/bin or /usr/local/bin).
3. The attacker crafts a malicious input string exceeding the buffer size allocated for the ‘-m’ parameter. This malicious string includes 564 bytes of padding.
4. The attacker appends a return address to the malicious string, pointing to a memory location containing the attacker’s shellcode.
5. The attacker executes the PInfo binary with the crafted malicious input as an argument to the ‘-m’ parameter. pinfo -m "A"*564 + <return_address>.
6. The buffer overflow occurs, overwriting the return address on the stack.
7. When the PInfo function returns, it jumps to the attacker-controlled address, executing the shellcode.
8. The attacker’s shellcode executes with the privileges of the user running PInfo. This can lead to privilege escalation if PInfo is run by a privileged user or via setuid.

Impact

Successful exploitation of this vulnerability allows a local attacker to execute arbitrary code with the privileges of the user running the vulnerable PInfo application. This could lead to sensitive data disclosure, unauthorized modification of system files, or complete system compromise. While the exact number of affected systems is unknown, any system running PInfo 0.6.9-5.1 is potentially vulnerable.

Recommendation

• Apply available patches or upgrade to a version of PInfo that addresses CVE-2016-20044.
• Monitor process creation events for executions of pinfo with unusually long arguments to the -m parameter, using the Sigma rule provided.
• Implement strict input validation for all command-line arguments in applications to prevent buffer overflows.