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Re: Re: [SC-L] Re: [Owasp-dotnet] RE: 4 Questions: Latest IE vulnerability, Firefox vs IE security, User vs Admin risk profile, and browsers coded in 100% Managed Verifiable code


From: "Matt Lidestri" <matt.lidestri () gmail com>
Date: Fri, 7 Apr 2006 00:36:19 -0400

Hello,

I have used AppArmor a bit, and must say that I like it a lot.  I have used
it on a few servers, and in some security competitions.  As a HIPS, it is
easy to use and fairly effective (from what I have seen).

I just saw your question and it sparked my curiousity.  From some quick
googling, I presume that cap_setuid allows a process or call to be passed as
another user (we'll say root for now).  I wondered if root was exempt from
the AppArmor rules (although I doubted it), so I configured my VMed
webserver to access a denied config file for mod_security, and then started
apache as root.  It failed with an error from AppArmor claiming that access
was denied to the configuration file.  I restored the permissions in
AppArmor and received a different error, apparently the Apache developers
were smart enough to disallow apache to be run as root.  Nonetheless,
AppArmor would not even let it get this far, so even root privileges cannot
override AppArmor profiles.

Regards,
Matt



On 4/6/06, Brian Eaton <eaton.lists () gmail com> wrote:

On 4/5/06, Crispin Cowan <crispin () novell com> wrote:
Pascal Meunier wrote:
 but as you posted an example profile with "capability setuid", I must
admit I am curious as to why an email client needs that.
Well now that is a very good question, but it has nothing to do with
AppArmor. The AppArmor learning mode just records the actions that the
application performs. With or without AppArmor, the Thunderbird mail
client is using cap_setuid. AppArmor gives you the opportunity to *deny*
that capability, so you can try blocking it and find out. But for
documentation on why Thunderbird needs it, you would have to look at
mozilla.org not the AppArmor pages.

Does cap_setuid give a program enough authority to break out of the
AppArmor profile?

Regards,
Brian

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Matt Lidestri
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