This is not an attack vector, because: 1. TCP SNs are usually moving. By default they don't need to, as that's part of the core ideology (thanks Postel!) but today they are usually moving. 2. Since connection has to be live before hand, servers request will be received by the client who will close the connection. 3. SNs provide only basic level of security, and this research proves, yet again for 35th straight year, that it's pretty good for what it is. 100+gigs of data just to be able to send a single packet over cleartext TCP is not bad at all. Universities and DCs may have this BW, but it isn't widespread. 4. This is just a bruteforce.