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- From: Jim Duncan
- Date: Mon Mar 12 22:39:45 2001
Rafi Sadowsky writes:
> No eavesdropping at all ? how can a TCP connection be hijacked if you're
> not on the connection path?
> (Or capable of diverting the connection past you -
> breaking routers/source_routing/<whatever>.... )
The attacker merely has to get his data into the TCP stream on the
victim host. No return traffic necessary. This means the attacker can
be _outside_ the victim's network if source address forgery isn't
prevented. This is _not_ new; same attack Mitnick used on Shimomura.
If you're on the path, you certainly don't need to guess the TCP ISN to
hijack a connection. This isn't new, either. :-)
By the way, Cisco stuff that has the fix we advertised in the security
advisory a couple of weeks ago is *NOT* vulnerable to the attack
announced by Guardent. The older stuff in IOS is not vulnerable either,
but some of our other products _are_ vulnerable. Of course, we already
announced that at http://www.cisco.com/warp/public/707/advisory.html .
I'll be along with a more official announcement, but I figured I'd
mention it here, too.
Jim Duncan, Product Security Incident Manager, Cisco Systems, Inc.
E-mail: <email@example.com> Phone(Direct/FAX): +1 919 392 6209