Threat Bulletin 0072: UDP reflection (DNS) against a tax authority portal platform in Southeast Asia

On Monday 7 June 2021 at 23:51 UTC, a UDP reflection (DNS) targeted a tax authority portal customer in Southeast Asia. The attack peaked at 32.3 Gbps and lasted 182 minutes. Traffic originated from 1731 autonomous systems in 23 countries, predominantly residential proxy networks.

Vector UDP reflection (DNS)
Peak 32.3 Gbps
Duration 182 min
Time to mitigation 0.079 s
Attack traffic reaching origin 0.010%
Legitimate traffic challenged 0.24%

Timeline

The attack was preceded by no stated motive. Edge packet filters identified the flood by source port and payload signature and dropped it at line rate across 16 points of presence.

What the customer saw

The customer’s status page stayed green throughout; they learned about the attack from our notification.

Recommendations

  • Enable authenticated origin pulls.
  • Add a dedicated rate limit for the targeted route.
  • Lower challenge thresholds on authentication endpoints during high-risk events.

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