Threat Bulletin 0371: GRE flood against a B2B SaaS platform in Iberia

On Tuesday 26 July 2022 at 06:27 UTC, a GRE flood targeted a B2B SaaS customer in Iberia. The attack peaked at 340.7 Gbps and lasted 76 minutes. Traffic originated from 3877 autonomous systems in 87 countries, predominantly residential proxy networks.

Vector GRE flood
Peak 340.7 Gbps
Duration 76 min
Time to mitigation 0.420 s
Attack traffic reaching origin 0.072%
Legitimate traffic challenged 0.46%

Timeline

The attack was preceded by a competitor’s product launch. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 32 points of presence.

What the customer saw

A brief increase in p99 latency of 174 ms during the first minute, then normal service.

Recommendations

  • Keep origin IPs out of public DNS history.
  • Enable log streaming to your SIEM for faster correlation.
  • Add a dedicated rate limit for the targeted route.

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