プロのハッカーであるサミュエルは、ボブとホストマシン間の既存のトラフィックを監視・傍受し、ボブのISNを予測しました。このISNを利用して、サミュエルはボブのIPアドレスを偽装したパケットをホストマシンに送信しました。ホストマシンはISNをインクリメントした<|パケットで応答しました。その結果、ボブの接続はハングアップし、サミュエルはボブに代わってホストマシンと通信できるようになりました。上記のシナリオにおいて、サミュエルが実行した攻撃の種類は何でしょうか?
正解:C
A TCP/IP hijack is an attack that spoofs a server into thinking it's talking with a sound client, once actually it' s communication with an assaulter that has condemned (or hijacked) the tcp session. Assume that the client has administrator-level privileges, which the attacker needs to steal that authority so as to form a brand new account with root-level access of the server to be used afterward. A tcp Hijacking is sort of a two-phased man- in-the-middle attack. The man-in-the-middle assaulter lurks within the circuit between a shopper and a server so as to work out what port and sequence numbers are being employed for the conversation.
First, the attacker knocks out the client with an attack, like Ping of Death, or ties it up with some reasonably ICMP storm. This renders the client unable to transmit any packets to the server. Then, with the client crashed, the attacker assumes the client's identity so as to talk with the server. By this suggests, the attacker gains administrator-level access to the server.
One of the most effective means of preventing a hijack attack is to want a secret, that's a shared secret between the shopper and also the server. looking on the strength of security desired, the key may be used for random exchanges. this is often once a client and server periodically challenge each other, or it will occur with each exchange, like Kerberos.