CVE-2020-1887
📋 TL;DR
This vulnerability in osquery allows attackers to perform man-in-the-middle (MITM) attacks on osquery's TLS traffic when proper certificate validation is not configured. It affects osquery deployments where TLS is used without a configured root chain of trust. Organizations using vulnerable osquery versions for endpoint monitoring are at risk.
💻 Affected Systems
- osquery
📦 What is this software?
Osquery by Linuxfoundation
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept, modify, or inject malicious data into osquery communications, potentially compromising endpoint monitoring data integrity and enabling lateral movement.
Likely Case
In environments without proper TLS certificate validation, attackers could intercept sensitive osquery data or inject false information into monitoring systems.
If Mitigated
With proper TLS certificate validation configured, the vulnerability has minimal impact as the SNI validation issue becomes irrelevant.
🎯 Exploit Status
Requires network position to intercept TLS traffic and knowledge of osquery TLS configuration. Exploitation depends on specific deployment configurations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.2.0
Vendor Advisory: https://www.facebook.com/security/advisories/cve-2020-1887
Restart Required: Yes
Instructions:
1. Upgrade osquery to version 4.2.0 or later. 2. Restart osquery services. 3. Verify TLS configurations still work correctly after upgrade.
🔧 Temporary Workarounds
Configure TLS certificate validation
allEnsure osquery TLS configurations include proper root certificate chain validation
# Configure osquery TLS flags with proper certificate validation
# Example: --tls_server_certs=/path/to/ca-bundle.crt
Disable TLS if not required
allIf TLS is not essential for your deployment, disable it temporarily
# Remove or comment out TLS-related flags in osquery configuration
🧯 If You Can't Patch
- Ensure all osquery TLS connections use properly configured certificate validation with trusted root certificates
- Implement network segmentation to limit potential MITM attack surfaces for osquery traffic
🔍 How to Verify
Check if Vulnerable:
Check osquery version with 'osqueryi --version' and verify if between 2.9.0 and 4.2.0, and check if TLS is configured without proper certificate validation.Check Version:
osqueryi --versionVerify Fix Applied:
Verify osquery version is 4.2.0 or later with 'osqueryi --version' and test TLS connections with certificate validation.📡 Detection & Monitoring
Log Indicators:
- Unexpected TLS handshake failures
- Certificate validation errors in osquery logs
- Unusual network connections to osquery endpoints
Network Indicators:
- Unencrypted osquery traffic when TLS expected
- MITM patterns in network traffic
- Unexpected certificates in TLS handshakes
SIEM Query:
source="osquery" AND (tls_handshake_failure OR certificate_error)