nanog mailing list archives

Re: TCP-ACK vulnerability (was RE: SSH on the router)


From: "Alexei Roudnev" <alex () relcom net>
Date: Wed, 9 Jun 2004 23:32:43 -0700


This is minor exploit - usually you set up VLAN1 interface with IP addres,
which is filterd out from outside. Moreover, there is not any good way to
find switch IP - it is transparent for user's devices.



On Mon, 7 Jun 2004, McBurnett, Jim wrote:
Aside from that, Use ACL's out the wazoo on the VTY lines and limit
access to
that to say 1 SSH enabled router or 1 IPSEC enabled router...

It doesn't really matter if you use SSH, Telnet or HTTP; if you can send
evil packets to the router/switch and it falls over and dies.

http://www.cisco.com/warp/public/707/cisco-sa-20040609-catos.shtml

IP Permit Lists will not provide any mitigation against this
vulnerability.

The race is on, who will find your switches first?



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