On Friday, March 21, 2014 12:40:40 PM Jan Lieskovsky wrote:
> But because both the RHEL6 SSG and RHEL6 STIG require this
> to be configured only in /etc/login.defs as opposed to
> /etc/pam.d/system-auth, it was questionable.
> While system certifications simply require checking that a system is
> configured in accordance with a published STIG, DSS will actually check to
> see that the intended requirements are actually enforced (i.e. actually
> attempt a non-compliant password as opposed to checking for applied
> So if we are all in agreement, could the SSG check and fix for this please
> be changed to include the setting that gets enforced (minlen=14 in
You are truly right that on Red Hat Enterprise Linux 5 the rule checks both
while in SSG content for Red Hat Enterprise Linux 6 just /etc/login.defs
But (slight) uncertainty comes from the following:
* in RHEL-5 the rule is titled "CCE-4541-1: Set password minimum length"
(thus somehow implying this should be system-wide check). While
* on RHEL-6 it is titled "22.214.171.124.a. Set Password Minimum Length in
login.defs (CCE-27002-5)" (thus somehow implying it should be checking just
login.defs file due the login.defs being emphasized in the title).
This makes me believe the original intention when creating RHEL-6 content
was to have just login.defs specific rule,
I strongly suspect that this is entirely a misunderstanding. Login.defs is
intended for use with shadow-utils. It provides a number of utilities that we
do not use at all. They are deleted in the build stage. Those same utilities
are provided by other packages such at util-linux. The other utilities not
being part of shadow-utils have no integration with that file except when the
upstream decided to use it. It is for this reason we labelled the setting as
"has no effect".
and then add a pam_cracklib
specific rule into / under: "Set Password Quality Requirements" subsection
of "Protect Accounts by Configuring PAM" section (maybe to have login.defs
and PAM rules separated into sections?) But looks the second part (adding
"minlen" check for PAM case) wasn't realized later.
The summary being -- you are correct, the PAM minlen check should be added
to the current form of RHEL-6 SSG content. The question is where we want to
have this check being added -- if into minimum password length login.defs
rule (like it's done on RHEL-5) or under the PAM section (where it might
seem to be more logical to belong to).
There should be no check of login.defs for minlen. You also have to
understand, there has been no engineering check of the validity of SSG
settings from top to bottom to compare against what we _designed_ as the
lockdown settings for common criteria. Common Criteria is the starting point
for the locking don of the system because that is where we had to demonstrate
everything to a third party lab assessing the security.
I can come with a patch proposal, just first need someone on the list
clarify the expected rule location. Shawn, can you possibly hint on this?
Thank you && Regards, Jan.
Jan iankko Lieskovsky / Red Hat Security Technologies Team
> Best regards,
> Trey Henefield, CISSP
> Senior IAVA Engineer
> Ultra Electronics
> Advanced Tactical Systems, Inc.
> 4101 Smith School Road
> Building IV, Suite 100
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> Tel: +1 512 327 6795 ext. 647
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> -----Original Message-----
> From: Steve Grubb [mailto:email@example.com]
> Sent: Thursday, March 20, 2014 7:59 AM
> To: scap-security-guide(a)lists.fedorahosted.org
> Cc: Trey Henefield
> Subject: Re: Minimum Password Length ...
> On Thursday, March 20, 2014 07:28:34 AM Trey Henefield wrote:
> > Nobody has seemed to respond to this. But this is an issue.
> > In /etc/login.defs, I have PASS_MIN_LEN set to 14, yet as a user, I
> > can set the following password 56tyghbn%^TY which only has 12
> > characters via the passwd command.
> In our common criteria setup, we have annotated the login.defs file with
> the following:
> # The evaluated configuration constraints are:
> # PASS_MAX_DAYS MAY be changed, must be <= 60 # PASS_MAX_DAYS MAY be
> changed, 0 < PASS_MIN_DAYS < PASS_MAX_DAYS # PASS_MIN_LEN has no effect
> in the evaluated configuration # PASS_WARN_AGE MAY be changed
> Note...has no effect...
> The intended way can be seen in system-auth:
> password requisite pam_cracklib.so try_first_pass retry=3 type=
> password sufficient pam_unix.so sha512 shadow nullok try_first_pass
> password required pam_deny.so
> Of these, cracklib is responsible for enforcing password policy. Checking
> its man page, it has something called minlen. Looking at the RHEL5 USGCB
> settings, this is in fact how it's set:
> sed -i "/pam_cracklib.so/s/retry=3/retry=3 minlen=12 dcredit=-1 ucredit=-1
> ocredit=-1 lcredit=-1 difok=3/" /etc/pam.d/system-auth
> So, to have 14, alter the above settings to correct it.
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