CVE-2020-36199
📋 TL;DR
CVE-2020-36199 is a command injection vulnerability in TinyCheck security monitoring software that allows attackers to execute arbitrary commands on affected systems. The vulnerability exists due to insufficient input validation in multiple components. Anyone running vulnerable versions of TinyCheck is affected.
💻 Affected Systems
- TinyCheck
📦 What is this software?
Tinycheck by Kaspersky
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root-level command execution, allowing complete control over the TinyCheck server and potential lateral movement to connected networks.
Likely Case
Remote code execution leading to data theft, installation of malware, or use of the system as a pivot point for further attacks.
If Mitigated
Limited impact with proper network segmentation and input validation controls in place, potentially restricting attacker to isolated environment.
🎯 Exploit Status
The advisory includes technical details that make exploitation straightforward for attackers with basic skills.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Commits 9fd360d and ea53de8 or later
Vendor Advisory: https://github.com/KasperskyLab/TinyCheck/security/advisories/GHSA-j2vj-mhr6-795m
Restart Required: Yes
Instructions:
1. Update TinyCheck to latest version from GitHub repository. 2. Apply commits 9fd360d and ea53de8. 3. Restart TinyCheck service. 4. Verify the fix by checking version.
🔧 Temporary Workarounds
Network Isolation
linuxRestrict network access to TinyCheck instances to only trusted management networks
iptables -A INPUT -s TRUSTED_NETWORK -p tcp --dport 8000 -j ACCEPT
iptables -A INPUT -p tcp --dport 8000 -j DROP
Input Validation Enhancement
allAdd additional input sanitization to vulnerable endpoints
🧯 If You Can't Patch
- Remove internet-facing access and restrict to internal management network only
- Implement strict firewall rules to limit which IP addresses can communicate with TinyCheck
🔍 How to Verify
Check if Vulnerable:
Check if TinyCheck version is older than commits 9fd360d and ea53de8 by examining git log or version filesCheck Version:
git log --oneline -n 5Verify Fix Applied:
Verify that commits 9fd360d and ea53de8 are present in git history: git log --oneline | grep -E '9fd360d|ea53de8'📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in system logs
- Suspicious process creation from TinyCheck service
- Unexpected network connections originating from TinyCheck host
Network Indicators:
- Anomalous outbound connections from TinyCheck server
- Unexpected payloads in HTTP requests to TinyCheck endpoints
SIEM Query:
process.name:python AND process.args:*sh* AND process.parent.name:tinycheck