CVE-2024-40722
📋 TL;DR
This vulnerability allows unauthenticated remote attackers to cause a stack-based buffer overflow in TCBServiSign Windows software by exploiting improper input validation. Attackers can temporarily disrupt the service by tricking users into visiting a spoofed website. Organizations using CHANGING Information Technology's TCBServiSign Windows Version are affected.
💻 Affected Systems
- TCBServiSign Windows Version
📦 What is this software?
Tcb Servisign by Changingtec
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption of TCBServiSign, potentially affecting business operations that rely on this software for digital signature services.
Likely Case
Temporary service disruption requiring restart of the TCBServiSign service, causing minor operational impact.
If Mitigated
No impact if proper network segmentation and web filtering prevent access to spoofed websites.
🎯 Exploit Status
Exploitation requires user to visit a malicious/spoofed website. No authentication required for the buffer overflow attack.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references
Vendor Advisory: https://www.twcert.org.tw/en/cp-139-7973-e10c6-2.html
Restart Required: Yes
Instructions:
1. Contact CHANGING Information Technology for patch details. 2. Apply the security update provided by the vendor. 3. Restart TCBServiSign service after patching.
🔧 Temporary Workarounds
Network Segmentation
allIsolate TCBServiSign servers from general user networks to reduce attack surface
Web Filtering
allImplement web filtering to block access to suspicious or spoofed websites
🧯 If You Can't Patch
- Implement strict network segmentation to isolate TCBServiSign servers
- Deploy web filtering solutions to block access to malicious/spoofed websites
🔍 How to Verify
Check if Vulnerable:
Check TCBServiSign version and compare with vendor's patched version informationCheck Version:
Check TCBServiSign application properties or vendor documentation for version informationVerify Fix Applied:
Verify TCBServiSign version matches vendor's patched version and test service functionality📡 Detection & Monitoring
Log Indicators:
- TCBServiSign service crashes or restarts
- Unusual API calls to TCBServiSign
Network Indicators:
- Traffic to known malicious domains
- Unusual outbound connections from user workstations
SIEM Query:
source="TCBServiSign" AND (event_type="crash" OR event_type="service_stop")