On Sunday 19 December 2021 at 08:02 UTC, a GRE flood targeted a tax authority portal customer in Central Europe. The attack peaked at 339.5 Gbps and lasted 52 minutes. Traffic originated from 2717 autonomous systems in 43 countries, predominantly hijacked home routers.
| Vector | GRE flood |
| Peak | 339.5 Gbps |
| Duration | 52 min |
| Time to mitigation | 0.121 s |
| Attack traffic reaching origin | 0.015% |
| Legitimate traffic challenged | 0.46% |
Timeline
The attack was preceded by a breaking political story. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 19 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.