Threat Bulletin 1382: Slowloris against a municipal services platform in Latin America

On Thursday 11 June 2026 at 10:07 UTC, a Slowloris targeted a municipal services customer in Latin America. The attack peaked at 181.8 million requests per second and lasted 132 minutes. Traffic originated from 1630 autonomous systems in 113 countries, predominantly compromised cloud VMs.

Vector Slowloris
Peak 181.8 million requests per second
Duration 132 min
Time to mitigation 0.842 s
Attack traffic reaching origin 0.021%
Legitimate traffic challenged 0.15%

Timeline

The attack was preceded by a hacktivist channel announcing the target. Request rates on the targeted routes exceeded their hourly baseline by a factor of 505 within 28 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 190 ms during the first minute, then normal service.

Recommendations

  • Review allow-listed partner ranges quarterly.
  • Keep origin IPs out of public DNS history.
  • Lower challenge thresholds on authentication endpoints during high-risk events.

8 thoughts on “Threat Bulletin 1382: Slowloris against a municipal services 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.

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