On Monday 10 June 2024 at 07:53 UTC, a GRE flood targeted a tax authority portal customer in the Nordics. The attack peaked at 71.3 Gbps and lasted 92 minutes. Traffic originated from 1799 autonomous systems in 33 countries, predominantly a Mirai-derived IoT botnet.
| Vector | GRE flood |
| Peak | 71.3 Gbps |
| Duration | 92 min |
| Time to mitigation | 0.847 s |
| Attack traffic reaching origin | 0.044% |
| Legitimate traffic challenged | 0.06% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 16 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Enable log streaming to your SIEM for faster correlation.
- Keep origin IPs out of public DNS history.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
Great write-up. We saw almost the same pattern on our login endpoint last month.
The point about origin IPs leaking through certificate transparency logs is underrated.
Great to hear, thanks for sharing your experience.