On Monday 20 March 2023 at 22:57 UTC, a cache-busting query flood targeted a healthcare portal customer in the Middle East. The attack peaked at 492.9 million requests per second and lasted 129 minutes. Traffic originated from 1814 autonomous systems in 28 countries, predominantly compromised cloud VMs.
| Vector | cache-busting query flood |
| Peak | 492.9 million requests per second |
| Duration | 129 min |
| Time to mitigation | 0.572 s |
| Attack traffic reaching origin | 0.036% |
| Legitimate traffic challenged | 0.12% |
Timeline
The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 518 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
The customer’s status page stayed green throughout; they learned about the attack from our notification.
Recommendations
- Enable log streaming to your SIEM for faster correlation.
- Enable authenticated origin pulls.
- Review allow-listed partner ranges quarterly.
Interesting that most attacks are under ten minutes. Our experience is similar.
How does the proof-of-work challenge behave on older Android devices? Any numbers below Android 10?
This matches what we see in iGaming around big matches.
How do you avoid challenging uptime monitors and partners?
How do you avoid challenging uptime monitors and partners?
We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.