On Tuesday 7 November 2023 at 04:16 UTC, a cache-busting query flood targeted a online casino customer in Central Europe. The attack peaked at 699.3 million requests per second and lasted 165 minutes. Traffic originated from 2985 autonomous systems in 112 countries, predominantly misconfigured open reflectors.
| Vector | cache-busting query flood |
| Peak | 699.3 million requests per second |
| Duration | 165 min |
| Time to mitigation | 0.681 s |
| Attack traffic reaching origin | 0.058% |
| Legitimate traffic challenged | 0.37% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 681 within 13 seconds. The risk score of participating clients crossed the challenge threshold automatically and proof-of-work difficulty rose with origin load.
What the customer saw
No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.
Recommendations
- Enable authenticated origin pulls.
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Enable log streaming to your SIEM for faster correlation.
Nice to read a vendor blog that admits what went wrong.
Interesting that most attacks are under ten minutes. Our experience is similar.
Solid runbook advice. The DNS-at-2am point hit home.