DOS-Attack against Gauntlet Firewall
-------------------------------------
We found out a security-issue with the Oracle-Proxy (SQL-Gateway) of
Gauntlet Firewall, Version 6 (manufactured by Secure Computing/NAI,
serversrunning Solaris 8, newest Patches installed). 

Abstract:
---------
Sending subsequent requests with invalid data to the firewalls SQL-gateway
results in an immediate crash. The firewall won't accept any further
connections on any SQL-gw that is defined in the rule base.
Secure Computing as vendor of Gauntlet could reproduce the DOS, patches or
bug fixes are not yet available.

Description:
-------------
We tried to monitor the firewall's sql-gw with our own monitoring-system to
make sure that we notice if it does not run. Some seconds later, the sql-gw
crashed and we were no longer able to connect the port.

Further investigation of the problem showed that the sql-gw-process can
easily be crashed on any Gauntlet-Firewall by simply connecting to it:

Try the following (_very_ basic) script, use your firewall's IP instead of
aaa.bbb.ccc.ddd, 
running sql-gw at the standard port 1521:

	for a in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
	do
		telnet aaa.bbb.ccc.ddd 1521
	done 

You will see that the last try to connect (#17) results in "Connection
refused" and the process of "sql-gw" is no longer running on the firewall.
==> A DOS against Gauntlet is very easy.

This is especially unpleasant, as Gauntlet is one of the few major
firewall-products that provide true application level security _and_ do have
a dedicated application-proxy for SQL (sql-net 1 + 2). 
In fact, many companies use Gauntlet especially to protect database-servers.

Solution/ Patches:
------------------
Secure Computing (www.securecomputing.com), the manufacturer of
Gauntlet-Firewall, has been informed by arago about the issue in August 2003
and has been able to reproduce the problem. 
Unfortunately, they have not yet managed to bring out a security-patch :-(
The only current solution they give is to use "plug-gws" instead of the
"sql-gws", which obviously weakens security _and_ performance a lot, as you
lose application-level security!   

Regards, 

Oliver Heinz + Thomas Neuderth


 
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 | arago,                     |  Oliver Heinz                              |
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