CVE-2020-25844
📋 TL;DR
CVE-2020-25844 is a stack buffer overflow vulnerability in NHIServiSignAdapter's digest generation function that allows remote attackers to execute arbitrary code without authentication. This affects systems running vulnerable versions of NHIServiSignAdapter software. Attackers can exploit this to gain control of affected systems.
💻 Affected Systems
- NHIServiSignAdapter
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Remote code execution allowing attackers to install malware, create backdoors, or disrupt services.
If Mitigated
Exploitation prevented through network segmentation, proper patching, and exploit mitigation controls.
🎯 Exploit Status
Stack overflow vulnerabilities with remote unauthenticated access typically have low exploitation complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references
Vendor Advisory: https://www.twcert.org.tw/tw/cp-132-4272-23ba4-1.html
Restart Required: Yes
Instructions:
1. Contact NHIServiSignAdapter vendor for security updates. 2. Apply the latest security patch. 3. Restart affected services. 4. Verify patch installation.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to NHIServiSignAdapter service to only trusted sources.
Use firewall rules to block external access to NHIServiSignAdapter ports
Service Disablement
windowsTemporarily disable NHIServiSignAdapter service if not required.
sc stop NHIServiSignAdapter
sc config NHIServiSignAdapter start= disabled
🧯 If You Can't Patch
- Implement strict network access controls to limit exposure
- Deploy exploit mitigation controls like DEP and ASLR
🔍 How to Verify
Check if Vulnerable:
Check if NHIServiSignAdapter service is running and compare version against vendor advisory.Check Version:
Check service properties or consult vendor documentation for version checkingVerify Fix Applied:
Verify service version matches patched version from vendor and test functionality.📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from NHIServiSignAdapter
- Service crashes or restarts
- Large input parameters to digest function
Network Indicators:
- Unexpected network connections from NHIServiSignAdapter host
- Exploit pattern detection in network traffic
SIEM Query:
source="NHIServiSignAdapter" AND (event_type="crash" OR process_name="cmd.exe" OR process_name="powershell.exe")