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RE: Infrastructure Filtering (was Re: Patching for Cisco vulnerability)

  • From: Barry Raveendran Greene
  • Date: Fri Jul 18 21:55:43 2003

As mentioned before, Receive Path ACL (rACL) is already in 12.0(21)S2 (and
forward) for the GSR and 12.0(24)S for the 7500. This is one way of doing
infrastructure filtering without packet filtering the data plane (customer
traffic). The second phase of Receive Path ACL (rACL) is going everywhere.
The marketing name is Control Plane Protocol (CPP) ... but it also takes
care of any packet punted to the receive path (i.e. packet with destination
address = to the router). It is MQC based (ACL + rate-limiting). Think of it
as a "TCP wrapper" for the receive path - but with the rate-limiting. The
rate limiting part is important. 

It will first show up in 12.2S (and forward) and then cross-port/back-port
through customer pressure (talk to your Cisco Account Teams). You'll see it
on everything for the small boxes (26XX) to switches (CAT6Ks) to the high
end (GSRs).

Personally, I see this "TCP Wrapper with Rate-Limit" around a router as
something that is going to be a requirement for all vendors on the Net. 

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of
> Charles Sprickman
> Sent: Friday, July 18, 2003 1:21 PM
> To: [email protected]
> Subject: Infrastructure Filtering (was Re: Patching for Cisco
> vulnerability)
> This has me wondering if there are any BCPs that touch on the whole idea
> of filtering traffic destined to your router, or what the advisory called
> "infrastructure filtering".  All in all, it seems like a good idea to
> block any direct access to router interfaces.  But as some have probably
> found already, it's a big pain in the arse.
> If I recall correctly, Rob's Secure IOS Template touches on filtering
> known services (the BGP listener, snmp), but what are people's feelings on
> maintaining filters on all interfaces *after* loading a fixed IOS?
> Thanks,
> Charles
> --
> Charles Sprickman
> [email protected]
> On Fri, 18 Jul 2003, Irwin Lazar wrote:
> >
> > Just out of curiosity, are folks just applying the Cisco patch or do you
> go through some sort of testing/validation process to ensure that the
> patch doesn't cause any other problems?  Given typical change management
> procedures how long is taking you to get clearance to apply the patch?
> >
> > I'm trying here to gauge the length of time before this vulnerability is
> closed out.
> >
> > irwin
> >