On Monday 28 June 2021 at 10:47 UTC, a ACK flood targeted a news publisher customer in the Middle East. The attack peaked at 233.5 Gbps and lasted 44 minutes. Traffic originated from 2027 autonomous systems in 105 countries, predominantly a rented booter service.
| Vector | ACK flood |
| Peak | 233.5 Gbps |
| Duration | 44 min |
| Time to mitigation | 0.225 s |
| Attack traffic reaching origin | 0.038% |
| Legitimate traffic challenged | 0.32% |
Timeline
The attack was preceded by a competitor’s product launch. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 26 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Add a dedicated rate limit for the targeted route.
- Keep origin IPs out of public DNS history.
- Enable log streaming to your SIEM for faster correlation.
Is the risk score exposed in the logs so we can build our own dashboards on it?
Thanks — sharing this with our on-call team.
Verified good bots and allow-listed partners bypass challenges entirely.
The point about origin IPs leaking through certificate transparency logs is underrated.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
Interesting that most attacks are under ten minutes. Our experience is similar.
The billing model is what got our finance team on board, honestly.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
Do you publish the edge IP ranges in a machine-readable format?
Our auditors asked for exactly this kind of incident evidence under DORA.