RE: SSL

["Scott, Richard" <Richard.Scott () BestBuy com>]

<snip>
        Just a quick question on SSL.  If I allow SSL outbound, and a user
browses a web site that is corrupt with something harmful like NIMDA, is it
possible that they will infect my network... and will the firewall not pass
it along without checking?

        If true, how can I combat this?  Is there a product that will stop
the packets and inspect them before being returned to the requester? 
<!snip>

Gary, 

It all depends on what measures are in place and the injection vector used
in contaminate your network.  SSL, like most tunnels protects from man in
the middle attacks.  What ever data is passed through the tunnel, travels
through it from one end to the other.  Simply using SSL as a mechanism does
not prevent infections from hostile web code.  SSL prevents the vector of
attack performed by sniffing the data.

In the instance of Nimda, one would have to look at the injection vector,
the method of attack.  Let's assume that it was a single vector, the
malicious java script code and one is trying to protect the user (client
side).  This can be prevented by two popular mechanisms.  1) educating users
to switch of Javascripting in a browser or 2) Firewall packet inspection.
There are other methods, but assuming that you do not want the code to
excute (rather than exploit a bug), these mechanisms would be used.  There
are politics to each mechanism, and there are better protection mechanisms
using signatures that are available.

So to answer you question, you can do packet inspection (processing could be
very high), you can do SSL, you can educate users.  A good security policy
would involve many methods and the reason is simple.  Multi-pronged attacks
that Nimda has. infected systems from servers to clients using different
vectors.  Using just one mechanism would not have prevented your system
getting infected (of course, you could have been on a Unix platform, the
only single mechanism that would have combated it).

readinteh archives in this mailing list you can have a sense of what the
professionals are considering... if you want to do packet inspection on SSL,
you may need to proxy the SSL data to be able to inspect it.

BTW - Does anyone have any pointers to be able to SSL packet inspection on
the data?


Cheers
r.
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