Re: Cisco IOS Denial of Service that affects most Cisco IOS routers- requires power cycle to recover

In article
<Pine.BSO.4.53.0307172223150.11409@rhiannon.precision-guesswork.com>,  Tina Bird <tbird@precision-guesswork.com> wrote:

> information on the detailed structure of the evil packets in these
> protocols is not yet public AFAIK.

The router has problems if it receives a packet, content irrelevant, that makes it to supervisor level claiming an IP protocol that it doesn't have code to handle.

The kickup to supervisor level happens when the packet is targeted directly at the router's IP address (per first Cisco advisory) or just has its TTL expire in transit past the router (per revised Cisco advisory).

Send enough packets (default 75), and the input queue is full. hping is enough of a launch platform for that--there's no need for questionable-source exploit binaries when testing.

Richard

-- 
My mailbox. My property. My personal space. My rules. Deal with it.
                        
http://www.river.com/users/share/cluetrain/

----------------------------------------------------------------------------
Attend the Black Hat Briefings & Training, July 28 - 31 in Las Vegas, the 
world's premier technical IT security event! 10 tracks, 15 training sessions, 
1,800 delegates from 30 nations including all of the top experts, from CSO's to 
"underground" security specialists.  See for yourself what the buzz is about!  
Early-bird registration ends July 3.  This event will sell out. www.blackhat.com
----------------------------------------------------------------------------