###############################################################
ID: S21SEC-025-en
Title: Cisco CSS 11000 Series DoS
Date: 04/07/2003
Status: Solution available
Scope: Interruption of service, high CPU load.
Platforms: All/Chassis CS800.
Author: ecruz, egarcia, jandre
Location: http://www.s21sec.com/en/avisos/s21sec-025-en.txt
Release: External
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				S 2 1 S E C

			   http://www.s21sec.com

                   Cisco CSS 11000 Series Denial of service



Description of vulnerability
----------------------------

A heavy storm of TCP SYN packets directed to the circuit address of the 
CSS 
can cause DoS on it, high cpu load or even sudden reboots.

The issue is known by cisco as the ONDM Ping failure (CSCdz00787). On the 
CS800 chassis the
system controller module (SCM) sends ONDM (online diagnostics monitor) 
pings to each SFP card
in order to see if they are alive, if the SCM doesn't get a response in 
about 30 seconds the
SCM will reboot the CS800 and there will be no core.

By attacking the circuit IP address of the CSS with SYN packets the 
traffic is sent up to the SCM
over the internal MADLAN ethernet interface. If this internal interface 
becomes overloaded
the ONDM ping request and response traffic can be dropped leading this to 
an internal DoS
since no internal comunications are available.

Any attacker could do this externally with a few sessions of NMAP and a 
cable/ADSL internet
connection.


Affected Versions and platforms
-------------------------------

This vulnerability affects the models 11800, 11150 and 11050 with chassis 
CS800.


Solution
--------

Upgrade to software release WebNS 5.00.110s or above.
http://www.cisco.com/en/US/products/hw/contnetw/ps789/prod_release_note0918
6a008014ee04.html

AcL's to protect the circuit address are recomended.


Additional information
----------------------

These vulnerabilities have been found and researched by:

 Eduardo Cruz		   ecruz@s21sec.com
 Emilin Garcia		 egarcia@s21sec.com
 Jordi Andre		  jandre@s21sec.com

You can find the last version of this warning in:

        http://www.s21sec.com/en/avisos/s21sec-025-en.txt

And other S21SEC warnings in http://www.s21sec.com/en/avisos/