On Saturday 31 August 2024 at 11:09 UTC, a ACK flood targeted a municipal services customer in the Nordics. The attack peaked at 7.6 Gbps and lasted 39 minutes. Traffic originated from 1717 autonomous systems in 54 countries, predominantly mobile carrier ranges.
| Vector | ACK flood |
| Peak | 7.6 Gbps |
| Duration | 39 min |
| Time to mitigation | 0.384 s |
| Attack traffic reaching origin | 0.083% |
| Legitimate traffic challenged | 0.15% |
Timeline
The attack was preceded by no stated motive. 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
A brief increase in p99 latency of 98 ms during the first minute, then normal service.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Review allow-listed partner ranges quarterly.
- Add a dedicated rate limit for the targeted route.