On Tuesday 13 April 2021 at 02:31 UTC, a ACK flood targeted a video streaming customer in the Middle East. The attack peaked at 198.2 Gbps and lasted 173 minutes. Traffic originated from 1744 autonomous systems in 21 countries, predominantly mobile carrier ranges.
| Vector | ACK flood |
| Peak | 198.2 Gbps |
| Duration | 173 min |
| Time to mitigation | 0.756 s |
| Attack traffic reaching origin | 0.012% |
| Legitimate traffic challenged | 0.70% |
Timeline
The attack was preceded by a ransom note demanding payment in Monero. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 32 points of presence.
What the customer saw
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Keep origin IPs out of public DNS history.
- Enable authenticated origin pulls.
- Add a dedicated rate limit for the targeted route.
Interesting that most attacks are under ten minutes. Our experience is similar.