Re: [cti] Question on indicator patterns

[Trey Darley <trey@kingfisherops.com>]

On 18.07.2016 08:50:23, Terry MacDonald wrote:
> Maybe this is where we need to separate the STIX certification into
> different categories to enable that differentiation to be recorded?
> 
> Full STIX compliance: full STIX including full CybOX objects and
> patterning.
> 
> Partial STIX compliance: STIX implementation of more than the
> specialized STIX compliance but not a full implementation of all
> parts of STIX.
> 
> Specialized STIX compliance: STIX and CybOX only focused on a
> specific subset of the language, and designed for a single purpose.
> 

The CybOX Patterning language was created to encompass matching on
both network and endpoint-related data. Yara does a fine job on the
endpoint as does Snort on the network, but the CybOX SC as could find
no open standard patterning language addressing both, the CybOX
Patterning language was developed.

Now clearly one would expect that a SIEM claiming to support STIX
Indicators would have the capability to handle matching on both
network and endpoint-related data. But one would *not* expect (for
example) a web proxy to know what to do with Windows Registry Keys but
a web proxy claiming to support STIX Indicators *should* be able to do
something sensible (and well-defined) upon receiving a STIX Indicator,
containing a CybOX Pattern enumerating URLs, IP addresses, etc.

From the perspective of claiming conformance to the standards, there's
obviously some variance to be accounted for depending on what type of
tool or product you're talking about

Currently we addressed this by inserting this text into the STIX
Indicator spec: "...and MUST be supported, as described by the CybOX
Patterning conformance specification."

We worked furiously on the CybOX Patterning spec last week but ran out
of time to address this. There is currently no text in the CybOX
Patterning spec describing conformance in these distinctly different
use cases but this is a known issue and one which we will be working
to address this week.

Hope that clears things up a bit! ^_^

-- 
Cheers,
Trey
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