CVE-2021-40175
📋 TL;DR
CVE-2021-40175 is a critical vulnerability in Zoho ManageEngine Log360 that allows attackers to upload arbitrary files without authentication, leading to remote code execution. This affects all Log360 installations before Build 5219, potentially giving attackers full control over affected systems.
💻 Affected Systems
- Zoho ManageEngine Log360
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining root/administrator privileges, data exfiltration, ransomware deployment, and persistent backdoor installation.
Likely Case
Attacker gains initial foothold, installs web shells or malware, and uses the compromised system as a pivot point for lateral movement within the network.
If Mitigated
Attack is blocked at network perimeter or detected before successful exploitation, limiting impact to failed attempts.
🎯 Exploit Status
Multiple public exploits available. Attack requires only HTTP access to vulnerable endpoint with crafted file upload request.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Build 5219 or later
Vendor Advisory: https://www.manageengine.com/log-management/readme.html#Build%205219
Restart Required: Yes
Instructions:
1. Download Log360 Build 5219 or later from ManageEngine website. 2. Backup current installation and configuration. 3. Run the installer to upgrade. 4. Restart the Log360 service. 5. Verify successful upgrade via version check.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict access to Log360 web interface to trusted IP addresses only
# Example firewall rule (Linux iptables): iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
# Example firewall rule (Windows): New-NetFirewallRule -DisplayName "Restrict Log360" -Direction Inbound -LocalPort 80 -RemoteAddress TRUSTED_IP -Protocol TCP -Action Allow
Web Application Firewall
allDeploy WAF with rules to block file upload attempts to vulnerable endpoints
# Example ModSecurity rule: SecRule REQUEST_URI "@rx /api/.*upload" "id:1001,phase:1,deny,msg:'Block Log360 upload attempt'"
🧯 If You Can't Patch
- Isolate Log360 server in separate network segment with strict access controls
- Implement application-level monitoring for file upload activities and suspicious web requests
🔍 How to Verify
Check if Vulnerable:
Check Log360 version via web interface (Help → About) or installation directory. If version is below Build 5219, system is vulnerable.Check Version:
# Windows: type "C:\Program Files\ManageEngine\Log360\conf\version.txt"
# Linux: cat /opt/ManageEngine/Log360/conf/version.txtVerify Fix Applied:
Verify version shows Build 5219 or higher. Test file upload functionality to ensure proper validation is in place.📡 Detection & Monitoring
Log Indicators:
- Unusual file upload requests to /api/* endpoints
- Web server logs showing POST requests with file upload parameters
- Creation of unexpected files in web directories
Network Indicators:
- HTTP POST requests to /api/*upload* endpoints from untrusted sources
- Unusual outbound connections from Log360 server
SIEM Query:
source="Log360" AND (uri="/api/*upload*" OR method="POST" AND uri CONTAINS "/api/")