Lesley, what version of SSG and OpenSCAP are you using?
On Sat, Jan 10, 2015 at 5:53 PM, Lesley Kimmel <ljkimmel99(a)hotmail.com>
Thanks a ton for all of that information, Greg. From what I've
reading I would have expected just what you described. However, all I had
to do to run the RHEL content on CentOS was to add
<platform>"cpe:/o:centos:centos:6"</platform> near the top of the
(xccdf) with no modification to the CPE or components...
On Jan 10, 2015 1:54 PM, Greg Elin <gregelin(a)gitmachines.com> wrote:
I know how you feel. SCAP seems like it should be easy because it is "just
XML". Then you dig into looking for a test and it gets confusing fast.
SCAP (Security Content Automation Protocol) is actually a set of multiple
standards and specifications that are used together to enable automatically
testing hundreds of nerd settings. Let me emphasize that: *SCAP is not a
single XML specification -- SCAP is multiple standards and specs*.
Whenever you give "SCAP Content" to a scanner to check a system
configurations you are giving the scanner multiple XML files representing
- XCCDF describes the checklist (Extensible Configuration Checklist
Description Format). 
- CCE are unique identifiers and descriptive material for specific
configuration settings (Common Configuration Enumeration). 
- OVAL is the XML that describes tests, including multi-part tests, that
assess if a CCE identified configuration setting is correct on a system.
(Open Vulnerability Assessment Language) 
- CPE is as unique string of text to uniquely identify a "platform" of
software, hardware, or application (Common Platform Enumeration). The idea
is that CPE string can be used to associate a checklist (XCCDF), a
configuration setting (CCE) or test (OVAL) with a specific platform. (Oy!)
And the list goes on. But to understand how to use SCAP-Security-Guide on
CentOS we only need to worry about XCCDF, CCE, OVAL, and CPE. (At least I
Almost all RHEL CCE's (config settings) and OVAL (test criterion) work on
CentOS. The exception are those settings/tests like the RHEL GPG key
installed which only make sense in relation to a RHEL subscription and do
not apply to CentOS.
So why does OpenSCAP run SCAP-Security-Guide on CentOS, but the results
come back "not applicable?" Two reasons:
1) Because the XCCDF in RHEL refers to CPE XML file that specifies RHEL
and not CentOS.
2) Because CPE platform string is verified with an OVAL test that checks
the RPMs for platform identification.
Thus, to get OpenSCAP to work on CentOS, we need to tell OpenSCAP to use a
CPE-dictionary.xml file that includes a CPE string for CentOS *and* we
need to have a corrected OVAL test that validates we are on CentOS.
And how do we do this reliability? Part of what I'm trying to do with my
software, GovReady , is to make things like this easier.
But you don't have to use GovReady. If you read the CentOS quick start in
the GovReady README, you will see link to a CentOS ssg-centos6-cpe-oval.xml
and ssg-centos6-cpe-oval.xml file that make the necessary adjustments. You
just need to copy them to your local CentOS server and then correctly
specify their path when running OpenSCAP. Like so:
oscap xccdf eval --oval-results --profile server --cpe
Alternatively, you could manually update the CPE and OVAL XML file using
(e.g., using a sed statement).
It's still kind of confusing for me. So I hope I have the above correct.
- Making FISMA compliance easier for innovators
On Fri, Jan 9, 2015 at 5:20 AM, Simon Lukasik <isimluk(a)fedoraproject.org>
On 01/08/2015 09:04 PM, Lesley Kimmel wrote:
I just downloaded the RHEL7 SCAP content and was 'playing' with it on a
CentOS 6 system. I found that in order to make the checks run I needed
to add 'cpe:/o:centos:centos:6' in a <platform> tag near the beginning
of the XCCDF component. I found this, in part, from various posts on the
interwebs. I'm really curious how this validation occurs and where the
information comes from on the target OS. Can anyone give me insight to
If you really wish to understand the things, your best bet would be to
read the actual standards.
For example XCCDF Standard document (NIST Interagency Report 7275) gives
basic insight into CPE matching.
Security Technologies, Red Hat, Inc.
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