I've run into the same problem.  I go with setting the global yum.conf as DISA says and then override the setting in a repos.d file for the repos that really need repo_gpgcheck to be off.


I think this was a back-ported requirement from DISA, not something originating from SSG.

-- 
Paul Arnold, CISSP
Cole Engineering Services, Inc.



On 11/13/2017 02:37 PM, Trevor Vaughan wrote:
Hi All,

I've been re-roaming through the SSG and this is probably the first of a many part thread regarding different checks.

TL;DR; The potential risk caused by enabling 'repo_gpgcheck' outweighs any potential benefit if TLS is enabled.

In my opinion, the following check should *only* be enabled if all of your repositories are internally managed xccdf_org.ssgproject.content_rule_ensure_gpgcheck_repo_metadata.

The reason for this is that YUM presently does not (to my knowledge) have any way to differentiate between package signing GPG keys and repo signing GPG keys.

This means that if, for instance, I host my packages via some shared Nexus, then I have to add the Nexus GPG key to my trust list for the repo.

I fundamentally do *not* want to do this! I shouldn't be allowing my Nexus maintainer to potentially install software on my system without my explicit knowledge.

You should use TLS, and the repo should have a trusted certificate there and that should be sufficient for the metadata until RPM can tell the difference between these two certificates.

Please let me know if I've missed something, but I don't remember seeing options to split out the two sets of certs.

Additionally, this is marked as 'high' severity and that seems to be massive overkill considering that 1) the packages are still signed and validated and 2) TLS is required.

--
Trevor Vaughan
Vice President, Onyx Point, Inc
(410) 541-6699 x788

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