Threat Bulletin 0235: WebSocket connection flood against a fashion retail platform in Central Europe

On Tuesday 18 January 2022 at 05:50 UTC, a WebSocket connection flood targeted a fashion retail customer in Central Europe. The attack peaked at 782.0 million requests per second and lasted 139 minutes. Traffic originated from 1774 autonomous systems in 41 countries, predominantly residential proxy networks.

Vector WebSocket connection flood
Peak 782.0 million requests per second
Duration 139 min
Time to mitigation 0.709 s
Attack traffic reaching origin 0.071%
Legitimate traffic challenged 0.51%

Timeline

The attack was preceded by an extortion email received two days earlier. Request rates on the targeted routes exceeded their hourly baseline by a factor of 417 within 13 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

No customer-visible impact. The on-call engineer was notified and acknowledged the incident from the dashboard.

Recommendations

  • Enable log streaming to your SIEM for faster correlation.
  • Keep origin IPs out of public DNS history.
  • Enable authenticated origin pulls.

7 thoughts on “Threat Bulletin 0235: WebSocket connection flood against a fashion retail platform in Central Europe”

  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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