On Monday 7 July 2025 at 01:28 UTC, a GRE flood targeted a tax authority portal customer in North America. The attack peaked at 338.1 Gbps and lasted 22 minutes. Traffic originated from 3256 autonomous systems in 93 countries, predominantly compromised cloud VMs.
| Vector | GRE flood |
| Peak | 338.1 Gbps |
| Duration | 22 min |
| Time to mitigation | 0.921 s |
| Attack traffic reaching origin | 0.032% |
| Legitimate traffic challenged | 0.34% |
Timeline
The attack was preceded by an extortion email received two days earlier. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 13 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.