nanog mailing list archives

Re: Cutting to the chase (was RE: ABOVE.NET SECURITY TRUTHS?)


From: Paul Ferguson <ferguson () cisco com>
Date: Fri, 28 Apr 2000 19:44:07 -0400


Well, yes, we have been trying to do "due diligence
to ensure that we publicly notify our customers, and
the public at-large, of any known security problems
with our products.

These are not dirty little secrets -- we believe that
our customers deserve to know, as soon as possible, when
we have found vulnerabilities in out products.

As stated in most on the advisories, we post these
security advisories to:

   cust-security-announce () cisco com
   bugtraq () securityfocus com
   first-teams () first org (includes CERT/CC)
   cisco () spot colorado edu
   comp.dcom.sys.cisco
   Various internal Cisco mailing lists

Secondly, and to the best of my knowledge, I know
of no instance where the Catalyst enable password
vulnerability has been used by an attacker to exploit
a customer's network.

For further information, see:

  http://www.cisco.com/warp/public/707/advisory.html

and

  http://www.cisco.com/warp/public/707/sec_incident_response.shtml

Cheers,

- paul

At 02:16 PM 04/28/2000 -0700, Roland Dobbins wrote:

First of all, there -is- a bug in the Catalyst Supervisor software revision
5.4.1 which basically disables the functionality of the enable password.  If
someone has the login password to the router, they can use the same password
to get to enable mode.  Yes, someone has to either a) get his password
sniffed internally or b) re-use the password on some external network which
allows it to get sniffed or c) use a weak and/or easily-guessable password
for this exploit to be used.  But your blanket statement about the enable
password on Cisco switches is incorrect.  And while shared segments are
generally a Bad Thing, there are certain instances in which they make sense.

See http://www.cisco.com/warp/public/707/catos-enable-bypass-pub.shtml for
more details.

Secondly, there's also a bug in the Cisco telnet daemon for IOS 11.3AA,
12.0(2)-12.0(6) and 12.0(7), excluding 12.0(7)S, 12.0(7)T, and 12.0(7)XE,
which allows a very easy DoS attacks against routers and switches running
those revs.  The bug ID is CSCdm70743, and more information can be found at
http://www.cisco.com/warp/public/707/iostelnetopt-pub.shtml .

Thirdly, 12-series IOSes can make use of ssh, but there are a lot of other
issues with the 12.x revs (see the above paragraph for an example) which
have prevented their wide-scale adoption.  Kerberos is certainly an option,
and a good one, but Monday-morning quarterbacking is really easy, especially
when one doesn't have direct knowledge of all the various factors involved,
nor any responsibility for maintaining the network in question.




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