A Simple active attack against TCP
Laurent Joncheray · 1995
This paper describes an active attack against the Transport Control Protocol (TCP) which allows a cracker to redirect the TCP stream through his machine thereby permitting him to bypass the protection offered by such a system as a one-time password [SKEY] or ticketing authentication [Kerberos]. The TCP connection is vulnerable to anyone with a TCP packet sniffer and generator located on the path followed by the connection. Some schemes to detect this attack are presented as well as some methods of prevention and some interesting details of the TCP protocol behaviors. 1 Introduction Passive attacks using sniffers are becoming more and more frequent on the Internet. The attacker obtains a user id and password that allows him to logon as that user. In order to prevent such attacks people have been using identification schemes such as one-time password [SKEY] or ticketing identification [Kerberos]. Though they prevent password sniffing on an unsecure network these methods are still vulne...