Compliance Impact

CVE-2016-20039 is a high-severity local buffer overflow vulnerability that allows arbitrary code execution, impacting confidentiality, integrity, and availability of the affected system.

Such a vulnerability could potentially lead to unauthorized access or control over sensitive data or system functions, which may result in non-compliance with standards and regulations like GDPR or HIPAA that require protection of data confidentiality and integrity.

However, the provided context and resources do not explicitly discuss or analyze the direct impact of this vulnerability on compliance with specific standards or regulations.

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Executive Summary

CVE-2016-20039 is a buffer overflow vulnerability in the Multi Emulator Super System (MESS) version 0.154-3.1. It occurs in the handling of the gamma parameter, where supplying an excessively long gamma value causes a stack buffer overflow. This overflow allows a local attacker to overwrite the instruction pointer with a controlled address, enabling them to execute arbitrary code or crash the application.

The vulnerability is triggered by passing a very long string (e.g., 4080 bytes of 'A's) to the -gamma command-line option of the mess executable. This causes the program to crash or allows the attacker to run their own code by controlling the program's execution flow.

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Impact Analysis

This vulnerability can have severe impacts including crashing the application or allowing an attacker to execute arbitrary code with the privileges of the user running the emulator. Since the exploit is local, an attacker needs access to run the vulnerable binary.

• Denial of Service: The application can be crashed, causing disruption.
• Arbitrary Code Execution: Attackers can run malicious code, potentially leading to system compromise.
• Confidentiality, Integrity, and Availability Impact: The vulnerability has high impact on all three, meaning sensitive data could be exposed or altered, and system availability could be affected.

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Detection Guidance

This vulnerability can be detected by attempting to run the vulnerable Multi Emulator Super System (MESS) executable with an excessively long string passed to the -gamma command-line option.

A practical detection method is to execute the following command on the system where MESS 0.154-3.1 is installed:

• mess -gamma $(python -c 'print("A"*4080)')

If the application crashes with a segmentation fault (SIGSEGV) and the instruction pointer is overwritten (e.g., with 0x41414141), this indicates the presence of the buffer overflow vulnerability.

Running the executable under a debugger such as gdb can help confirm the overflow by showing the crash and overwritten registers.

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Mitigation Strategies

Immediate mitigation steps include restricting or preventing local users from executing the vulnerable MESS 0.154-3.1 binary, as the exploit requires local access.

If possible, update or patch the Multi Emulator Super System software to a version that addresses this buffer overflow vulnerability.

In the absence of an official patch, consider removing or disabling the vulnerable executable to prevent exploitation.

Additionally, monitor system logs and user activity for attempts to run the executable with suspiciously long -gamma parameters.

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