On Thursday 18 August 2022 at 04:16 UTC, a SYN flood targeted a tax authority portal customer in North America. The attack peaked at 220.8 Gbps and lasted 94 minutes. Traffic originated from 3031 autonomous systems in 37 countries, predominantly a Mirai-derived IoT botnet.
| Vector | SYN flood |
| Peak | 220.8 Gbps |
| Duration | 94 min |
| Time to mitigation | 0.110 s |
| Attack traffic reaching origin | 0.073% |
| Legitimate traffic challenged | 0.49% |
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 30 points of presence.
What the customer saw
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Review allow-listed partner ranges quarterly.
- Add a dedicated rate limit for the targeted route.
- Enable authenticated origin pulls.
Nice to read a vendor blog that admits what went wrong.
Machine-readable ranges are at /ips.json and via the API.