CVE-2020-37131: Product Key Explorer DoS Vulnerability

CVE-2020-37131 Overview

CVE-2020-37131 is a denial of service vulnerability affecting Nsauditor Product Key Explorer version 4.2.2.0. The vulnerability allows local attackers to crash the application by inputting a specially crafted registration key. Specifically, an attacker can generate a payload consisting of 1000 bytes of repeated characters and paste it into the 'Key' input field, triggering an application crash due to improper input validation.

Critical Impact

Local attackers can cause a denial of service condition by crashing the Product Key Explorer application through malformed input in the registration key field.

Affected Products

• Nsauditor Product Key Explorer version 4.2.2.0

Discovery Timeline

• 2026-02-05 - CVE CVE-2020-37131 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2020-37131

Vulnerability Analysis

This vulnerability is classified under CWE-120 (Buffer Copy without Checking Size of Input), commonly known as a classic buffer overflow. The application fails to properly validate the length of user-supplied input in the registration key field before copying it to a fixed-size buffer. When an attacker provides an excessively long string (1000 bytes of repeated characters), the application cannot handle the oversized input, resulting in a crash.

The local attack vector requires user interaction, as the attacker must either have local access to the system or convince a user to paste the malicious payload. While this limits the attack surface, it remains a concern for environments where the application is deployed on shared systems or where social engineering attacks are feasible.

Root Cause

The root cause of this vulnerability is improper input validation in the registration key handling routine. The application does not enforce adequate bounds checking on the input length before processing the registration key data. This results in a buffer overflow condition (CWE-120) when the input exceeds expected boundaries, causing memory corruption and subsequent application crash.

Attack Vector

The attack is executed locally and requires user interaction. An attacker must craft a payload of approximately 1000 bytes consisting of repeated characters and input this string into the 'Key' field of the Product Key Explorer application. Upon submission or processing of this oversized input, the application crashes due to the buffer overflow condition.

The exploitation is straightforward and does not require sophisticated technical skills. The attacker simply needs to generate a string of repeated characters (such as 'A' repeated 1000 times) and paste it into the registration key input field. No authentication or elevated privileges are required to trigger the vulnerability.

Detection Methods for CVE-2020-37131

Indicators of Compromise

• Application crash events associated with Nsauditor Product Key Explorer 4.2.2.0
• Abnormal termination logs showing memory access violations
• User reports of application instability when entering registration information
• System event logs indicating unexpected process termination for ProductKeyExplorer.exe

Detection Strategies

• Monitor for repeated application crashes of Product Key Explorer through Windows Event Viewer
• Implement endpoint detection rules to alert on buffer overflow crash signatures
• Deploy application whitelisting to prevent unauthorized modification or exploitation attempts
• Review system stability logs for patterns indicating denial of service attacks

Monitoring Recommendations

• Configure crash dump collection for Product Key Explorer to capture forensic evidence
• Enable application crash monitoring through endpoint protection platforms
• Track clipboard activity for unusually long strings being pasted into application input fields
• Set up alerts for repeated process terminations of the affected application

How to Mitigate CVE-2020-37131

Immediate Actions Required

• Restrict access to Nsauditor Product Key Explorer to trusted users only
• Consider removing or replacing the affected software version 4.2.2.0 if not business-critical
• Implement endpoint protection monitoring for application crashes and anomalous behavior
• Review and apply any available vendor updates from Nsauditor

Patch Information

No official patch information is available in the CVE data. Users should check the NSA Auditor Homepage for potential updates or newer versions that may address this vulnerability. Additional technical details are available in the Exploit-DB #48284 entry and the VulnCheck Denial of Service Advisory.

Workarounds

• Limit user access to the Product Key Explorer application to prevent unauthorized exploitation attempts
• Deploy the application in isolated environments where local access is strictly controlled
• Implement application control policies to monitor and restrict input to the registration key field
• Consider using alternative product key management solutions until a patched version is available

# Configuration example - Restrict application access via Windows NTFS permissions
# Limit Product Key Explorer access to administrators only
icacls "C:\Program Files\ProductKeyExplorer\ProductKeyExplorer.exe" /inheritance:r
icacls "C:\Program Files\ProductKeyExplorer\ProductKeyExplorer.exe" /grant:r Administrators:RX