CVE-2020-18077
📋 TL;DR
A buffer overflow vulnerability in FTPShell Server v6.83 allows attackers to crash the service via specially crafted requests to the Virtual Path Mapping component. This affects anyone running the vulnerable version of FTPShell Server, potentially disrupting file transfer operations.
💻 Affected Systems
- FTPShell Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service causing FTPShell Server to crash, disrupting all FTP operations until service restart.
Likely Case
Service crash requiring manual restart, causing temporary disruption to file transfers.
If Mitigated
No impact if patched or workarounds implemented; service remains stable.
🎯 Exploit Status
Public proof-of-concept demonstrates simple DoS via buffer overflow; no authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown - no official patch identified
Vendor Advisory: No vendor advisory found
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
Network Segmentation
allRestrict access to FTPShell Server to trusted networks only
Configure firewall rules to allow only specific IP ranges
Service Monitoring and Restart
windowsImplement automated monitoring and restart for FTPShell service
sc query FTPShell
net start FTPShell
🧯 If You Can't Patch
- Replace FTPShell with alternative FTP server software
- Implement strict network access controls and monitor for crash events
🔍 How to Verify
Check if Vulnerable:
Check FTPShell Server version in application interface or registry: HKEY_LOCAL_MACHINE\SOFTWARE\FTPShell\Server\VersionCheck Version:
reg query "HKLM\SOFTWARE\FTPShell\Server" /v VersionVerify Fix Applied:
Verify version is not 6.83; test with known exploit payloads if possible📡 Detection & Monitoring
Log Indicators:
- FTPShell service crash events
- Application error logs showing buffer overflow
Network Indicators:
- Unusual FTP traffic patterns
- Multiple connection attempts to Virtual Path Mapping
SIEM Query:
source="FTPShell" AND (event_id=1000 OR "buffer overflow" OR "access violation")