On Saturday 11 January 2025 at 07:39 UTC, a Slowloris targeted a online payments customer in Iberia. The attack peaked at 306.7 million requests per second and lasted 72 minutes. Traffic originated from 3505 autonomous systems in 109 countries, predominantly misconfigured open reflectors.
| Vector | Slowloris |
| Peak | 306.7 million requests per second |
| Duration | 72 min |
| Time to mitigation | 0.566 s |
| Attack traffic reaching origin | 0.048% |
| Legitimate traffic challenged | 0.48% |
Timeline
The attack was preceded by a breaking political story. Request rates on the targeted routes exceeded their hourly baseline by a factor of 545 within 12 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
- Lower challenge thresholds on authentication endpoints during high-risk events.
- Review allow-listed partner ranges quarterly.
- Enable authenticated origin pulls.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
This matches what we see in iGaming around big matches.
Interesting that most attacks are under ten minutes. Our experience is similar.
Great write-up. We saw almost the same pattern on our login endpoint last month.
We had the exact false-positive issue with CGNAT carriers. The weighting change makes sense.
Would love a follow-up on how you handle HTTP/3 fingerprinting.
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.