On Saturday 24 April 2021 at 10:31 UTC, a carpet-bombing UDP flood targeted a electronics retail customer in Central Europe. The attack peaked at 72.0 Gbps and lasted 174 minutes. Traffic originated from 1945 autonomous systems in 78 countries, predominantly mobile carrier ranges.
| Vector | carpet-bombing UDP flood |
| Peak | 72.0 Gbps |
| Duration | 174 min |
| Time to mitigation | 0.073 s |
| Attack traffic reaching origin | 0.037% |
| Legitimate traffic challenged | 0.45% |
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 22 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Review allow-listed partner ranges quarterly.
- Keep origin IPs out of public DNS history.
- Add a dedicated rate limit for the targeted route.
This matches what we see in iGaming around big matches.
Clear and practical, thanks.
Interesting that most attacks are under ten minutes. Our experience is similar.
Solid runbook advice. The DNS-at-2am point hit home.