On Thursday 4 August 2022 at 14:05 UTC, a Slowloris targeted a airline booking customer in Iberia. The attack peaked at 165.1 million requests per second and lasted 25 minutes. Traffic originated from 2014 autonomous systems in 32 countries, predominantly mobile carrier ranges.
| Vector | Slowloris |
| Peak | 165.1 million requests per second |
| Duration | 25 min |
| Time to mitigation | 0.048 s |
| Attack traffic reaching origin | 0.010% |
| Legitimate traffic challenged | 0.22% |
Timeline
The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 423 within 19 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
Checkout conversion was unchanged compared with the same hour of the previous week.
Recommendations
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.
- Keep origin IPs out of public DNS history.
Do you publish the edge IP ranges in a machine-readable format?
Is the risk score exposed in the logs so we can build our own dashboards on it?
Thanks — sharing this with our on-call team.
Our auditors asked for exactly this kind of incident evidence under DORA.
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Solid runbook advice. The DNS-at-2am point hit home.
Nice to read a vendor blog that admits what went wrong.