Threat Bulletin 1438: search endpoint flood against a online payments platform in the UK

On Thursday 27 August 2026 at 21:48 UTC, a search endpoint flood targeted a online payments customer in the UK. The attack peaked at 811.7 million requests per second and lasted 100 minutes. Traffic originated from 3552 autonomous systems in 12 countries, predominantly a headless-browser farm.

Vector search endpoint flood
Peak 811.7 million requests per second
Duration 100 min
Time to mitigation 0.683 s
Attack traffic reaching origin 0.023%
Legitimate traffic challenged 0.47%

Timeline

The attack was preceded by a competitor’s product launch. Request rates on the targeted routes exceeded their hourly baseline by a factor of 424 within 37 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

A brief increase in p99 latency of 170 ms during the first minute, then normal service.

Recommendations

  • Enable log streaming to your SIEM for faster correlation.
  • Keep origin IPs out of public DNS history.
  • Lower challenge thresholds on authentication endpoints during high-risk events.

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