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Re: Holes in the firewall of Mac OS X Leopard

On Mon, 29 Oct 2007, Brandon S. Allbery KF8NH wrote:

> On Oct 29, 2007, at 17:49 , Juergen Schmidt wrote:
> >- if you set it to "Block all incoming connections" it still allows access
> >to certain system services. We could access the ntp daemon that is running
> >per default over the internet. In a LAN based scenario, we were able to
> >query the Netbios naming service even with full blocking enabled.
> The firewall in Tiger, and presumably Leopard, only affects TCP services by
> default (you can enable UDP filtering in the Advanced settings).  So no change
> here from the status quo.

Nope -- the behaviour we observed did not depend on the protocol by any 
means. For example we were able to connect to a netcat server listening on 
a TCP port despite of "Set access to specific services and programs" and 
an empty list of allowed services.

There is no way to "enable UDP filtering" in Leopard either -- at least I 
have not found any. In fact the firewall does not use ipfw rules at all. 

bye, ju

Juergen Schmidt, editor-in-chief heise Security www.heise-security.co.uk
GPG-Key: 0x38EA4970,  5D7B 476D 84D5 94FF E7C5  67BE F895 0A18 38EA 4970