Threat Bulletin 0478: GRE flood against a healthcare portal platform in Latin America

On Wednesday 21 December 2022 at 22:25 UTC, a GRE flood targeted a healthcare portal customer in Latin America. The attack peaked at 370.7 Gbps and lasted 79 minutes. Traffic originated from 1973 autonomous systems in 30 countries, predominantly residential proxy networks.

Vector GRE flood
Peak 370.7 Gbps
Duration 79 min
Time to mitigation 0.167 s
Attack traffic reaching origin 0.022%
Legitimate traffic challenged 0.11%

Timeline

The attack was preceded by a breaking political story. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 36 points of presence.

What the customer saw

A brief increase in p99 latency of 111 ms during the first minute, then normal service.

Recommendations

  • Enable log streaming to your SIEM for faster correlation.
  • Review allow-listed partner ranges quarterly.
  • Lower challenge thresholds on authentication endpoints during high-risk events.

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