Threat Bulletin 1423: HTTP POST flood against a tax authority portal platform in Latin America

On Thursday 6 August 2026 at 01:34 UTC, a HTTP POST flood targeted a tax authority portal customer in Latin America. The attack peaked at 863.4 million requests per second and lasted 49 minutes. Traffic originated from 1881 autonomous systems in 97 countries, predominantly residential proxy networks.

Vector HTTP POST flood
Peak 863.4 million requests per second
Duration 49 min
Time to mitigation 0.303 s
Attack traffic reaching origin 0.056%
Legitimate traffic challenged 0.18%

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 317 within 7 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 81 ms during the first minute, then normal service.

Recommendations

  • Enable authenticated origin pulls.
  • Lower challenge thresholds on authentication endpoints during high-risk events.
  • Enable log streaming to your SIEM for faster correlation.

8 thoughts on “Threat Bulletin 1423: HTTP POST flood against a tax authority portal platform in Latin America”

  1. We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.

  2. We moved from a scrubbing provider to always-on last year; time to mitigation went from minutes to basically nothing.

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