TCPShield experienced a major incident on November 12, 2025, lasting 3h 32m. The incident has been resolved; the full update timeline is below.
Update timeline
- resolved Nov 12, 2025, 09:39 AM UTC
At around 1:48 UTC, our network globally received a series of sophisticated TCP attacks aiming to replicate legitimate traffic. These attacks were executed at high packet rate, peaking as high as 3Gpps (billion packets per second) measured from the borders. By 1:55 UTC, we understood the full scope of the bypassing nature of the attack. By 03:38 UTC, tests have been written to match the corresponding mitigation to the new attack vector. By 03:45 UTC, the patch has been deployed globally to the network. And finally, at 05:20 UTC, we received 2 hits of the same attack vector with no further impact to our network. We continue to record and monitor all network flows towards our border and remain available to act quickly should any additional attempts arise.