CVE-2020-37200: NetShareWatcher Buffer Overflow Flaw

CVE-2020-37200 Overview

CVE-2020-37200 is a buffer overflow vulnerability (CWE-121: Stack-based Buffer Overflow) affecting NetShareWatcher version 1.5.8.0. The vulnerability exists in the registration key input field, where insufficient bounds checking allows attackers to trigger an application crash by supplying oversized input. Specifically, a 1000-character payload pasted into the registration key field causes a denial of service condition.

Critical Impact

Local attackers can crash the NetShareWatcher application by exploiting the buffer overflow in the registration key input, resulting in denial of service.

Affected Products

• NetShareWatcher 1.5.8.0

Discovery Timeline

• 2026-02-11 - CVE-2020-37200 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2020-37200

Vulnerability Analysis

This vulnerability is classified as a stack-based buffer overflow (CWE-121), which occurs when data written to a buffer exceeds the allocated space on the program's call stack. In the case of NetShareWatcher 1.5.8.0, the registration key input field fails to properly validate the length of user-supplied input before copying it to a fixed-size buffer.

The attack requires local access and user interaction, as an attacker must either directly access the application or social engineer a user into pasting a malicious payload into the registration key field. While the immediate impact is limited to application availability (denial of service), stack-based buffer overflows can potentially be leveraged for more severe attacks such as code execution if proper memory protections are not in place.

Root Cause

The root cause is improper input validation in the registration key processing logic. The application allocates a fixed-size buffer for the registration key but does not enforce length restrictions on user input. When a user supplies input exceeding the buffer's capacity (demonstrated with a 1000-character payload), the excess data overwrites adjacent memory on the stack, corrupting the program's execution state and causing a crash.

Attack Vector

The attack vector is local, requiring an attacker to have access to the system where NetShareWatcher is installed. The exploitation process involves:

1. Opening NetShareWatcher 1.5.8.0 on the target system
2. Navigating to the registration interface
3. Generating or preparing a payload of approximately 1000 characters
4. Pasting the oversized payload into the registration key input field
5. The application crashes due to the buffer overflow condition

Technical details and proof-of-concept information can be found in the Exploit-DB #47860 entry and the VulnCheck Advisory.

Detection Methods for CVE-2020-37200

Indicators of Compromise

• Unexpected crashes of the NetShareWatcher.exe process
• Windows Error Reporting events indicating access violations or stack corruption in NetShareWatcher
• Memory dump files generated by NetShareWatcher crashes showing stack overflow patterns

Detection Strategies

• Monitor for repeated crashes of NetShareWatcher application through Windows Event Log analysis
• Implement application monitoring to detect abnormal termination events for NetShareWatcher.exe
• Use endpoint detection solutions to identify buffer overflow exploitation attempts targeting desktop applications

Monitoring Recommendations

• Configure Windows Event Log monitoring for application crash events related to NetShareWatcher
• Deploy SentinelOne agents to detect and alert on exploitation attempts targeting memory corruption vulnerabilities
• Review crash dump files for evidence of exploitation attempts

How to Mitigate CVE-2020-37200

Immediate Actions Required

• Identify all systems running NetShareWatcher 1.5.8.0 within the environment
• Consider uninstalling or disabling NetShareWatcher until a patched version is available
• Restrict local access to systems running the vulnerable application
• Implement application whitelisting to prevent unauthorized users from accessing NetShareWatcher

Patch Information

No vendor patch information is currently available for this vulnerability. Check the NSA Auditor Tool website for potential updates or newer versions that may address this issue.

Workarounds

• Avoid pasting untrusted content into the registration key field
• Restrict local user access to systems running NetShareWatcher to trusted personnel only
• Consider replacing NetShareWatcher with alternative network share monitoring solutions that do not contain known vulnerabilities
• Implement strict input validation at the network boundary if the application accepts external data