Certified Ethical Hacker (CEH) Practice Question

In a blind TCP session hijacking, the attacker cannot see the live packets, so the only way to insert malicious data is to forge packets that look legitimate to the server. TCP considers a packet valid only if its sequence number falls within the receiver's current acceptance window-that is, it matches or is ahead of the next sequence number the server expects from the client. If the attacker guesses that next expected sequence number, the server will accept the spoofed packet and process its payload, effectively giving the attacker control of the session. Predicting the client's receive window size, the server's congestion window, or the negotiated MSS does not by itself allow data injection; without the exact sequence number, the server discards the packet as out-of-order or invalid.