We do monitor the file itself, but we would also like to verify that the root password is
being changed within the required timeframe. Monitoring the shadow file for changes is a
start, but that file could be changed for other unrelated reasons, so we also want to
confirm which specific audit record(s) are now being generated when a local account
password is changed.
I see several pam-related messages that were generated the last time the root password
was changed on a RHEL 7.9 system, but it's not clear if those event types could get
generated for other reasons as well. The only clue that those audit events probably
represent a password change attempt is that the exe=/usr/bin/passwd
Thanks again,
Karen Wieprecht
-----Original Message-----
From: linux-audit-bounces(a)redhat.com <linux-audit-bounces(a)redhat.com> On Behalf Of
Richard Guy Briggs
Sent: Thursday, July 8, 2021 8:47 PM
To: warron.french <warron.french(a)gmail.com>
Cc: Linux-audit(a)redhat.com
Subject: [EXT] Re: The format of password change audit events seems to have changed, Can
you confirm the correct record type ?
APL external email warning: Verify sender linux-audit-bounces(a)redhat.com before clicking
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On 2021-07-08 18:53, warron.french wrote:
This is an interesting topic.
Please, can you tell me what audit rule you are using that generates
such records about root's (*or any other account's) password change?*
This is a built-in to the userspace password management tools and not a kernel-triggered
rule.
You could duplicate the effort by monitoring /etc/shadow for writes if you are really
paranoid about those tools being subverted.
Sincerely, thank you.
--------------------------
Warron French
On Thu, Jul 8, 2021 at 3:27 PM Steve Grubb <sgrubb(a)redhat.com> wrote:
> On Thursday, July 8, 2021 2:19:54 PM EDT Wieprecht, Karen M. wrote:
> > I've noticed that the messages I'm searching for in splunk to
> > show root password changes no longer seem to be in the same
> > format. Most of our systems run RHEL7 release 7.9, and I believe
> > this is a recent change (I've only noticed this problem in the
> > past 3 months or so?), but we do have an older 7.5 system, so I was able to
use that to compare against
> > the 7.5 to identify what's changed. I wanted to confirm which record
> I
> > should be using now since there are several that get generated now
> >
> > The key differences seem to be in the message generated and the
> > keyname being used for the account being targeted, but I wanted
> > to confirm that there isn't some other record I should be looking
> > at to verify that the root password was changed in the required
> > timeframe since I see several records being generated from a
> > password change, none of which include anything as conclusive as the old
message that showed the operation as a
> > "password change". Here are some fo the fields I'm looking at:
> >
> > type=USER_CHAUTHOK
> > exe=/usr/bin/passwd
> > [acct targeted for the passwd change]:
> > id=root (old format)
> > acct=root (latest format)
> > msg
> > msg='op=change password (old format)
> > msg='op=PAM:chauthok (latest format)
> >
> > If you can confirm whether this is the info I should be using now
> > to confirm password changes, that would be much appreciated.
>
> I don't have a RHEL 7.9 machine to compare against. I can set one up
> in about a week. On 7.6 the event looks like this:
>
> type=USER_CHAUTHTOK msg=audit(1625771196.574:162): pid=5113 uid=0
> auid=1000
> ses=1 subj=unconfined_u:unconfined_r:passwd_t:s0-s0:c0.c1023
> msg='op=change
> password id=1000 exe="/usr/bin/passwd" hostname=rhel7.3 addr=?
> terminal=pts/0
> res=success'
>
> The problem is that "op= change passwd" has a space in it and will
> not parse right. I have been trying to correct instances of this so
> that things parse correctly. Not everyone runs their changes by me
> for comment. So, its possible that the change was made to fix the
> space, but usually I suggest people add an underscore.
>
> I'll into it more next week.
>
> -Steve
- RGB
--
Richard Guy Briggs <rgb(a)redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
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