The Hidden HTTP Tunnel detection identifies the use of HTTP traffic to covertly communicate with external command and control servers by encapsulating another protocol within HTTP sessions. Attackers use this technique to evade detection by blending malicious traffic with legitimate HTTP traffic, making it difficult to identify without advanced analysis.
Scenario 1: An internal host communicates with an external IP over HTTP, displaying consistent communication patterns and unusual payload sizes. Further investigation reveals the presence of malware using HTTP tunneling to exfiltrate data.
Scenario 2: A security audit detects long-duration HTTP sessions from an internal host to a suspicious domain. Analysis shows the sessions contain hidden command and control traffic, indicating the host is compromised and part of a botnet.
If this detection indicates a genuine threat, the organization faces significant risks:
Hidden HTTP tunnels can be used to exfiltrate sensitive data from the organization, leading to potential financial and reputational damage.
Attackers can use these tunnels to maintain persistent remote access, allowing them to control compromised hosts undetected.
The use of encrypted tunnels can bypass traditional network security measures, increasing the risk of undetected malicious activity.
Review logs for unusual HTTP traffic patterns, focusing on long or multiple sessions, size variability, and communication with uncommon external domains.
Investigate the internal host generating the traffic for signs of compromise, such as malware, unauthorized software, or unexpected configurations.
Look for other signs of compromise, such as abnormal login attempts, unusual system behavior, or other related detections.
Confirm if any authorized activities or legitimate services could explain the detected HTTP tunnel behavior.