On Monday 20 January 2025 at 17:31 UTC, a ACK flood targeted a B2B SaaS customer in Central Europe. The attack peaked at 13.6 Gbps and lasted 167 minutes. Traffic originated from 1061 autonomous systems in 106 countries, predominantly residential proxy networks.
| Vector | ACK flood |
| Peak | 13.6 Gbps |
| Duration | 167 min |
| Time to mitigation | 0.694 s |
| Attack traffic reaching origin | 0.082% |
| Legitimate traffic challenged | 0.48% |
Timeline
The attack was preceded by a publicly announced sales event. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 36 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.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.