CVE-2020-37201: NetShareWatcher Buffer Overflow Flaw

CVE-2020-37201 Overview

CVE-2020-37201 is a buffer overflow vulnerability (CWE-120) affecting NetShareWatcher version 1.5.8.0. The vulnerability exists in the registration name input field, where an attacker can trigger an application crash by supplying an excessively long string. Specifically, a 1000-character payload pasted into the 'Name' field during registration causes a denial of service condition by crashing the application.

Critical Impact

Local attackers can cause a denial of service by exploiting a buffer overflow in the registration name input field, crashing NetShareWatcher and disrupting network share monitoring capabilities.

Affected Products

• NetShareWatcher 1.5.8.0

Discovery Timeline

• 2026-02-11 - CVE CVE-2020-37201 published to NVD
• 2026-02-12 - Last updated in NVD database

Technical Details for CVE-2020-37201

Vulnerability Analysis

This buffer overflow vulnerability (CWE-120: Buffer Copy without Checking Size of Input) occurs when the application fails to properly validate the length of user-supplied input in the registration name field. The application allocates a fixed-size buffer for the name input but does not implement adequate bounds checking before copying user data into this buffer.

When a user or attacker provides input exceeding the expected buffer size—specifically a payload of 1000 characters or more—the application writes data beyond the allocated memory boundaries. This memory corruption leads to an uncontrolled application crash, resulting in a denial of service condition.

The local attack vector requires user interaction, as the victim must be running the vulnerable application while the attacker provides or induces the malicious input through the user interface.

Root Cause

The root cause of CVE-2020-37201 is improper input validation in the registration component of NetShareWatcher. The application fails to enforce appropriate length restrictions on the 'Name' field input before copying data to an internal buffer. This classic buffer overflow pattern allows data to overflow the intended storage area, corrupting adjacent memory and causing the application to crash.

Attack Vector

The attack is executed locally and requires user interaction. An attacker must either have access to the target system or convince a user to paste a malicious payload into the registration name field. The exploitation process involves:

1. Generating a payload consisting of 1000 or more characters
2. Accessing the NetShareWatcher registration dialog
3. Pasting the payload into the 'Name' input field
4. Triggering the input processing which causes the buffer overflow

The attack results in immediate application crash due to memory corruption. While the current documented impact is denial of service (application availability), buffer overflows can potentially be leveraged for more severe attacks if the memory layout allows for code execution.

Detection Methods for CVE-2020-37201

Indicators of Compromise

• NetShareWatcher application crashes or unexpected termination events
• Windows application error logs showing NetShareWatcher.exe crash events
• Large string inputs (1000+ characters) observed in application logs or memory dumps
• Repeated application restarts or stability issues

Detection Strategies

• Monitor Windows Event Logs for application crash events related to NetShareWatcher.exe
• Implement endpoint detection rules to identify abnormal application termination patterns
• Deploy application crash monitoring to detect repeated denial of service attempts
• Use SentinelOne Singularity to monitor for exploitation attempts targeting buffer overflow conditions

Monitoring Recommendations

• Enable Windows Error Reporting to capture crash dump information for analysis
• Configure endpoint monitoring to alert on NetShareWatcher process crashes
• Implement user behavior analytics to detect unusual activity around the registration interface
• Review system stability reports for patterns indicating exploitation attempts

How to Mitigate CVE-2020-37201

Immediate Actions Required

• Avoid using the registration functionality in NetShareWatcher 1.5.8.0 until a patch is available
• Consider replacing NetShareWatcher with an alternative network share monitoring solution
• Restrict access to systems running the vulnerable application to trusted users only
• Monitor for application crashes and investigate any occurrences

Patch Information

No vendor patch information is currently available for CVE-2020-37201. Users should monitor the NSA Auditor Homepage for security updates. Additional technical details are available through the VulnCheck Advisory and Exploit-DB #47848.

Workarounds

• Avoid using the registration feature in the vulnerable application version
• Implement application-level input filtering if a third-party wrapper or security tool is available
• Consider using network-based controls to restrict access to systems running the vulnerable software
• Deploy endpoint protection solutions like SentinelOne to detect and respond to exploitation attempts