An administrator received a FortiAnalyzer alert that a 1 ТВ disk filled up in a...

The excessive DNS log requests with random subdomains suggest a DNS exfiltration attack, where attackers encode and transmit data via DNS queries. Since this technique can use both UDP and TLS (DoH - DNS over HTTPS), a comprehensive security approach is needed.

Using an IPS profile with DNS exfiltration-specific signatures allows FortiGate to:

● Detect and block abnormal DNS query patterns often used in exfiltration.

● Inspect encrypted DNS (DoH, DoT) traffic if SSL inspection is enabled.

● Identify known exfiltration domains and techniques based on FortiGuard threat intelligence.