Re: [NANOG] IOS rootkits

[Mark Smith <nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org>]

On Sun, 18 May 2008 13:33:53 -0700
Dragos Ruiu <dr () kyx net> wrote:

> On 18-May-08, at 7:11 AM, Suresh Ramasubramanian wrote:
> > 2. It can be prevented by what's widely regarded as BCP on router
> > security, and has been covered at *nog, in cisco training material,
> > etc etc for quite some time now.
> >
> > I am much less concerned about security conferences discussing this
> > than about the (highly uninformed) publicity that accompanies these
> > conferences.
>
>
> I'm not going to touch the disclosure or not debate... it's been done.
>
> But I will agree to disagree with you about the above two points.
>
> First of all about prevention, I'm not at all sure about this being  
> covered by existing router security planning / BCP.
> I don't believe most operators reflash their routers periodically, nor  
> check existing images (particularly because the tools for this  
> integrity verification don't even exist). If I'm wrong about this I  
> would love to be corrected with pointers to the tools.
<snip>

Cisco publish an MD5 sum (and BSD 'sum' IIRC) for the IOS image just
before you hit the download page, which you can record and then verify
after downloading (although they could make this a *lot* easier to do
by posting it after, or before and after the download).

There is also a /md5 option for the IOS verify command which can be
used to generate an MD5 sum for an IOS image stored on a router.

Regards,
Mark.

-- 

        "Sheep are slow and tasty, and therefore must remain constantly
         alert."
                                   - Bruce Schneier, "Beyond Fear"

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