CVE-2021-47894: Switch Port Mapping Tool DoS Vulnerability

CVE-2021-47894 Overview

CVE-2021-47894 is a denial of service vulnerability affecting Managed Switch Port Mapping Tool version 2.85.2. The vulnerability allows attackers to crash the application by creating an oversized buffer. Specifically, attackers can generate a 10,000-character buffer and paste it into the IP Address and SNMP Community Name input fields, triggering an application crash due to improper resource allocation limits.

This vulnerability is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating that the application fails to properly validate and limit the size of user-supplied input before allocating resources to process it.

Critical Impact
Attackers with local access can crash the Managed Switch Port Mapping Tool application, disrupting network administrators' ability to map and manage switch ports in their infrastructure.

Affected Products

Managed Switch Port Mapping Tool version 2.85.2

Discovery Timeline

2026-01-23 - CVE CVE-2021-47894 published to NVD
2026-01-26 - Last updated in NVD database

Technical Details for CVE-2021-47894

Vulnerability Analysis

This denial of service vulnerability stems from improper input validation in the Managed Switch Port Mapping Tool. The application fails to enforce appropriate size constraints on user-supplied input in critical form fields. When a user inputs an excessively long string (approximately 10,000 characters) into either the IP Address field or the SNMP Community Name field, the application attempts to process this data without adequate bounds checking.

The lack of input length validation causes the application to allocate an unexpectedly large buffer, leading to resource exhaustion or memory corruption that results in an application crash. This vulnerability requires local access and user interaction to exploit, as an attacker must be able to interact with the application's graphical user interface.

Root Cause

The root cause of CVE-2021-47894 is the absence of proper input length validation and resource allocation limits (CWE-770). The application's input handling routines do not implement maximum length restrictions on the IP Address and SNMP Community Name fields, allowing oversized data to be processed. Standard IP addresses are at most 15 characters (for IPv4) or 45 characters (for IPv6 with zone ID), and SNMP community strings are typically under 32 characters. The application should reject or truncate inputs exceeding these reasonable limits.

Attack Vector

The attack vector for this vulnerability is local, requiring an attacker to have direct access to a system running the Managed Switch Port Mapping Tool. The attack flow involves:

Attacker generates a buffer containing approximately 10,000 characters
Attacker opens the Managed Switch Port Mapping Tool application
Attacker pastes the oversized buffer into either the IP Address field or SNMP Community Name field
The application attempts to process the input without proper bounds checking
The application crashes due to resource exhaustion or memory corruption

While this vulnerability requires local access and user interaction, it could be leveraged as part of a larger attack chain to disrupt network management operations. For detailed technical information about the exploitation method, refer to the Exploit-DB entry #49566 and the VulnCheck Advisory.

Detection Methods for CVE-2021-47894

Indicators of Compromise

Unexpected crashes or termination of the Managed Switch Port Mapping Tool application
Application event logs showing memory allocation failures or unhandled exceptions
Presence of unusually large input strings in application configuration or temporary files
User reports of application instability when entering IP addresses or SNMP community names

Detection Strategies

Monitor application crash reports and Windows Error Reporting for Managed Switch Port Mapping Tool crashes
Implement endpoint detection rules to identify attempts to paste large text buffers into the application
Review application logs for error messages related to input processing or memory allocation failures
Deploy SentinelOne endpoint protection to detect and alert on application crash patterns indicative of exploitation attempts

Monitoring Recommendations

Enable application crash monitoring on systems running Managed Switch Port Mapping Tool
Configure SIEM rules to correlate multiple application crashes from the same endpoint
Implement user activity monitoring for network management workstations
Establish baseline application behavior to detect anomalous crashes or restarts

How to Mitigate CVE-2021-47894

Immediate Actions Required

Identify all systems running Managed Switch Port Mapping Tool version 2.85.2
Check for updated versions from the vendor at the Switch Port Mapper download page
Restrict access to network management workstations to authorized personnel only
Implement endpoint protection solutions like SentinelOne to monitor for exploitation attempts
Consider using alternative network mapping tools until a patched version is available

Patch Information

Organizations should check the Switch Port Mapper Tool website for updated versions that address this denial of service vulnerability. Review the VulnCheck Advisory for the latest remediation guidance.

Workarounds

Restrict physical and remote access to systems running the vulnerable application
Implement application whitelisting to prevent unauthorized users from launching the tool
Use clipboard monitoring tools to detect and block paste operations containing unusually large text strings
Consider deploying the application in a sandboxed environment to limit crash impact
Train users to avoid pasting data from untrusted sources into the application's input fields

bash

# Inventory check for affected software
# Search for Managed Switch Port Mapping Tool installations
wmic product where "name like '%Switch Port%'" get name,version

# Windows PowerShell alternative
Get-WmiObject -Class Win32_Product | Where-Object { $_.Name -like "*Switch Port*" } | Select-Object Name, Version