On Tuesday 29 June 2021 at 22:38 UTC, a UDP reflection (DNS) targeted a tax authority portal customer in Western Europe. The attack peaked at 89.8 Gbps and lasted 143 minutes. Traffic originated from 922 autonomous systems in 87 countries, predominantly mobile carrier ranges.
| Vector | UDP reflection (DNS) |
| Peak | 89.8 Gbps |
| Duration | 143 min |
| Time to mitigation | 0.766 s |
| Attack traffic reaching origin | 0.033% |
| Legitimate traffic challenged | 0.50% |
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 33 points of presence.
What the customer saw
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
- Enable log streaming to your SIEM for faster correlation.
Carpet bombing is nasty. Good to see a clear explanation of it.
The billing model is what got our finance team on board, honestly.
Thanks! Yes — the risk score and its components are included in every log record.