Balwinder Singh wrote:

>I have developed an application, which I believe can provide 100%
>security against various attacks.I can hear people laughing. Hmm..
>The applications is called Execution Flow Control (EFC).
>Details of software can be found at http://203.197.88.14/efc
>
This sounds somewhat similar to our SubDomain
<http://immunix.org/subdomain.html> product, which profiles applications
in terms of what files they may access. It sounds very similar to the
approach taken by Systrace
<http://www.citi.umich.edu/u/provos/systrace/>, Okena
<http://newsroom.cisco.com/dlls/corp_012403.html> and Entercept
<http://www.entercept.com/>, which like EFC, profile applications in
terms of which system calls they may invoke.

At least Systrace also allows you to profile the arguments presented to
syscalls, so you can fake SubDomain's file access control paradigm. This
is important, because "touch /etc/pointless" is rather different from
"touch /etc/hosts.allow". It is unclear from the EFC documents if EFC
supports argument profiling.

The advantages of syscall access control:

* more expressive: if you know that application Foo has no business
calling e.g. mkdir, then you can catch exploits that try to
leverage that kind of thing.

The advantages of SubDomain:

* It is easier to generate a file access profile for an application
than a syscall profile. Instead, SubDomain just has a long list of
prohibited/dangerous syscalls for confined applications, letting
the admin think about important stuff (which files to grant access
to) and ignore less important stuff (who cares if *this* app calls
getpid?).
* Syscall mediation is prone to race conditions inside the kernel if
it is implemented using syscall interposition.

Crispin

--
Crispin Cowan, Ph.D. http://immunix.com/~crispin/
Chief Scientist, Immunix http://immunix.com
http://www.immunix.com/shop/

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