On Thursday 18 November 2021 at 04:35 UTC, a ACK flood targeted a developer platform customer in the Benelux. The attack peaked at 309.2 Gbps and lasted 89 minutes. Traffic originated from 2410 autonomous systems in 37 countries, predominantly compromised cloud VMs.
| Vector | ACK flood |
| Peak | 309.2 Gbps |
| Duration | 89 min |
| Time to mitigation | 0.036 s |
| Attack traffic reaching origin | 0.011% |
| Legitimate traffic challenged | 0.27% |
Timeline
The attack was preceded by a hacktivist channel announcing the target. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 18 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.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
Is the risk score exposed in the logs so we can build our own dashboards on it?