Threat Hunting C2 over HTTPS Connections Using the TLS Certificate

Source: Active Countermeasures

Author: Faan Rossouw

URL: https://www.activecountermeasures.com/threat-hunting-c2-over-https-connections-using-the-tls-certificate/

ONE SENTENCE SUMMARY: The article discusses techniques for threat hunting command and control (C2) activity hidden within HTTPS connections using TLS certificates.

MAIN POINTS:

1. Threat actors often hide C2 traffic within encrypted HTTPS connections.
2. TLS certificates can provide valuable indicators for detecting malicious activities.
3. Legitimate certificates are sometimes misused by attackers for C2 communications.
4. Anomalies in TLS certificate metadata help identify suspicious HTTPS connections.
5. Certificate attributes like issuer, validity period, and domain can indicate malicious usage.
6. Automated tools can analyze TLS certificates efficiently to detect threats.
7. Inspecting certificates is essential for effective threat hunting practices.
8. TLS certificate fingerprinting helps identify known malicious infrastructure.
9. Monitoring certificate issuance patterns can uncover malicious actors’ infrastructure.
10. Properly implemented TLS certificate inspection enhances cybersecurity posture.

TAKEAWAYS:

1. Leverage TLS certificate metadata analysis to detect hidden C2 channels.
2. Pay attention to unusual certificate attributes to identify potential threats.
3. Integrate certificate inspection into existing threat hunting methodologies.
4. Automate TLS certificate monitoring to efficiently spot anomalies.
5. Maintain updated threat intelligence on TLS certificate misuse for effective detection.