Cisco Security Advisory: Crafted TCP Packet Can Cause Denial of Service

Unanswered Question
Jan 30th, 2007

Hello,

Question regarding the work around for the recent Cisco Security Advisory (cisco-sa-20070124). The link to this advisory is here:http://www.cisco.com/en/US/customer/products/products_security_advisory09186a00807cb0e4.shtml#vuln

The work around says to create an access-list for example:

access-list 150 permit tcp TRUSTED_HOSTS MASK INFRASTRUCTURE_ADDRESSES MASK

So trusted_hosts, is that the hosts on my network?

Infrastructure_addresses, is this my routers

I'm not sure what they are saying here. If anyone could shed some light, that would be great

Thanks

Mike

I have this problem too.
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timmk Wed, 01/31/2007 - 10:42

Pretty close. Trusted hosts SHOULD be hosts that are A.,trusted and B., require access to those devices. So as an example "TRUSTES_HOSTS" could be management stations, admin desktops, or whatever is required to have access and you is "trusted". Ideally infrastructure address space should only be reachable from trusted users that need access and no one else. Infrastructure space would likely include addresses for routers, firewalls, switches , authentication servers, monitoring servers, basically anything that makes the network run and keeps it alive. Hope this helps.

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