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

["Christopher L. Morrow" <christopher.morrow () mci com>]

On Wed, 9 Jun 2004, Alexei Roudnev wrote:

> This is minor exploit - usually you set up VLAN1 interface with IP addres,

'usually' doesn't cover everyone, and some people didn't think ahead or
realize that they might have a problem with this :(

> which is filterd out from outside. Moreover, there is not any good way to
> find switch IP - it is transparent for user's devices.

dns is your friend here :( People love to name things such that they are
easy to remember. cat5500.floor2.build3.you.com

> > 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?