CVE-2021-47895
📋 TL;DR
CVE-2021-47895 is a denial of service vulnerability in Nsauditor 3.2.2.0 where attackers can crash the application by inputting an overly large buffer into the Event Description field. This affects all users running the vulnerable version of Nsauditor network auditing software. The vulnerability requires local or remote access to the application interface.
💻 Affected Systems
- Nsauditor Network Security Auditor
📦 What is this software?
Nsauditor by Nsasoft
⚠️ Risk & Real-World Impact
Worst Case
Complete application crash leading to service disruption, potential data loss if unsaved work exists, and interruption of network auditing operations.
Likely Case
Application crash requiring manual restart, temporary disruption of network monitoring or auditing functions.
If Mitigated
Minimal impact with proper input validation and application hardening in place.
🎯 Exploit Status
Exploit requires access to the application interface. Proof of concept demonstrates using 10,000-character buffer of 'U' characters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.2.3.0 or later
Vendor Advisory: https://www.nsauditor.com/
Restart Required: Yes
Instructions:
1. Download latest version from nsauditor.com. 2. Uninstall current version. 3. Install updated version. 4. Restart system if prompted.
🔧 Temporary Workarounds
Input Validation Restriction
windowsImplement input validation to limit Event Description field length
Not applicable - requires code modification
Application Access Control
windowsRestrict access to Nsauditor interface to trusted users only
Use Windows firewall to block unnecessary access to Nsauditor ports
🧯 If You Can't Patch
- Restrict application access to only necessary administrative users
- Implement monitoring for repeated application crashes or unusual input patterns
🔍 How to Verify
Check if Vulnerable:
Check Nsauditor version in Help > About. If version is 3.2.2.0, system is vulnerable.Check Version:
Check Help > About menu within Nsauditor applicationVerify Fix Applied:
After update, verify version is 3.2.3.0 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Application crash events in Windows Event Logs
- Repeated Nsauditor process termination
Network Indicators:
- Unusual traffic patterns to Nsauditor interface
- Multiple connection attempts followed by service disruption
SIEM Query:
EventID=1000 AND Source='Application Error' AND ProcessName='nsauditor.exe'