On Monday 10 March 2025 at 06:25 UTC, a GRE flood targeted a sports betting customer in the Nordics. The attack peaked at 344.2 Gbps and lasted 189 minutes. Traffic originated from 1527 autonomous systems in 21 countries, predominantly misconfigured open reflectors.
| Vector | GRE flood |
| Peak | 344.2 Gbps |
| Duration | 189 min |
| Time to mitigation | 0.681 s |
| Attack traffic reaching origin | 0.005% |
| Legitimate traffic challenged | 0.77% |
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 38 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Keep origin IPs out of public DNS history.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
Solid runbook advice. The DNS-at-2am point hit home.
Our auditors asked for exactly this kind of incident evidence under DORA.
This matches what we see in iGaming around big matches.
Solid runbook advice. The DNS-at-2am point hit home.
Verified good bots and allow-listed partners bypass challenges entirely.
Thanks — sharing this with our on-call team.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Great write-up. We saw almost the same pattern on our login endpoint last month.