One extra comment - should the UID of 500 be hardcoded here or should it be 
pulled from /etc/login.defs, or the equivalent file for other distros? I know 
the breakpoint between system and regular user ids has changed over the years.

-Rob

________________________________
From: Rodolfo Martínez [[email protected]]
Sent: Wednesday, June 08, 2016 12:32 PM
To: SCAP Security Guide
Subject: EXTERNAL: Re: Use /etc/passwd directly instead of sources in NSS

Hi Gabe,

Yes, I am more familiar with OVAL syntax now and I understand why it is not 
working.

The problem in my OVAL test is in this part:

  <ind:textfilecontent54_object id="object_at_system_accounts_allow_list" 
version="1">
    <ind:filepath>/etc/passwd</ind:filepath>
    <ind:pattern operation="pattern 
match">^([^:]+):[^:]+:[\d]+:[\d]+:[^:]*:[^:]+:[^:]*$</ind:pattern>
    <ind:instance operation="greater than or equal" 
datatype="int">1</ind:instance>
    <filter action="include">state_at_system_accounts_etc_passwd</filter>
  </ind:textfilecontent54_object>

  <ind:textfilecontent54_state id="state_at_system_accounts_etc_passwd" 
version="1">
    <ind:filepath>/etc/passwd</ind:filepath>
    <ind:pattern operation="pattern 
match">^[^:]+:[^:]+:([\d]+):[\d]+:[^:]*:[^:]+:[^:]*$</ind:pattern>
    <ind:instance operation="greater than or equal" 
datatype="int">1</ind:instance>
    <ind:subexpression operation="greater than or equal" 
datatype="int">500</ind:subexpression>
  </ind:textfilecontent54_state>


'<ind:subexpression>' in block in'<ind:textfilecontent54_state>' is getting the 
subexpression pattern from '<ind:textfilecontent54_object>' which contains the 
username; so comparing a username to be an integer 'greater or equal to 500' is 
not valid.


My question is much simpler now:

How can get all usernames from /etc/passwd that have UID greater or equal to 
500 without using password_object? I have been trying to do this for many days 
now without any luck.

Thanks for your time

--
Rodolfo Martínez

On Tue, Jun 7, 2016 at 1:03 PM, Gabe Alford 
<[email protected]<mailto:[email protected]>> wrote:
Hello Rodolfo,

I just did a quick glance as I currently don't have the cycles to look into 
this but the "state_at_system_accounts_at_allow_uid" exclude filter is where 
this is not working. It is not filtering UIDs greater than 1 or 500 for that 
matter.
Specifically this subexpression is what is failing:

<ind:subexpression operation="greater than or equal" 
datatype="int">500</ind:subexpression>

Gabe

On Thu, Jun 2, 2016 at 8:52 PM, Rodolfo Martínez 
<[email protected]<mailto:[email protected]>> wrote:
Hi mpreisler,

Thanks for you suggestion in IRC.

This what I have so far, but it is still not working. I feel I am close, but it 
is not working yet. I would appreciate any suggestion

<def-group>
  <definition class="compliance" id="at_system_accounts" version="1">
    <metadata>
      <title>No system accounts in /etc/at.allow</title>
      <affected family="unix">
        <platform>CentOS 5</platform>
        <platform>Red Hat Enterprise Linux 5</platform>
      </affected>
      <description>Group owner for /etc/at.allow and /etc/at.deny must 
exist.</description>
    </metadata>
    <criteria>
      <criterion test_ref="test_at_system_accounts_at_allow" />
    </criteria>
  </definition>

  <!-- This variable should get all users from /etc/passwd that has UID >= 500 
-->
  <local_variable id="var_at_system_accounts_allow_list" comment="Accounts 
Allowed" datatype="string" version="1">
    <object_component item_field="subexpression" 
object_ref="object_at_system_accounts_allow_list" />
  </local_variable>

  <ind:textfilecontent54_object id="object_at_system_accounts_allow_list" 
version="1">
    <ind:filepath>/etc/passwd</ind:filepath>
    <ind:pattern operation="pattern 
match">^([^:]+):[^:]+:[\d]+:[\d]+:[^:]*:[^:]+:[^:]*$</ind:pattern>
    <ind:instance operation="greater than or equal" 
datatype="int">1</ind:instance>
    <filter action="include">state_at_system_accounts_etc_passwd</filter>
  </ind:textfilecontent54_object>

  <ind:textfilecontent54_state id="state_at_system_accounts_etc_passwd" 
version="1">
    <ind:filepath>/etc/passwd</ind:filepath>
    <ind:pattern operation="pattern 
match">^[^:]+:[^:]+:([\d]+):[\d]+:[^:]*:[^:]+:[^:]*$</ind:pattern>
    <ind:instance operation="greater than or equal" 
datatype="int">1</ind:instance>
    <ind:subexpression operation="greater than or equal" 
datatype="int">500</ind:subexpression>
  </ind:textfilecontent54_state>


  <!-- Test to check that there is no system accounts in /etc/at.allow -->
  <ind:textfilecontent54_test check="all" check_existence="none_exist" 
id="test_at_system_accounts_at_allow" comment="Testing /etc/at.allow for system 
accounts" version="1">
    <ind:object object_ref="object_at_system_accounts_allow" />
  </ind:textfilecontent54_test>

  <ind:textfilecontent54_object comment="/etc/at.allow" 
id="object_at_system_accounts_allow" version="1">
    <!-- Get all users from /etc/at.allow -->
    <ind:filepath>/etc/at.allow</ind:filepath>
    <ind:pattern operation="pattern match">^(.+)$</ind:pattern>
    <ind:instance operation="greater than or equal" 
datatype="int">1</ind:instance>
    <!-- Exclude root -->
    <filter action="exclude">state_at_system_accounts_at_allow_root</filter>
    <!-- Exclude all user accounts -->
    <filter action="exclude">state_at_system_accounts_at_allow_uid</filter>
  </ind:textfilecontent54_object>

  <ind:textfilecontent54_state id="state_at_system_accounts_at_allow_root" 
version="1">
    <ind:text>root</ind:text>
  </ind:textfilecontent54_state>

  <unix:password_state id="state_at_system_accounts_at_allow_uid" version="1">
    <unix:username var_ref="var_at_system_accounts_allow_list" var_check="at 
least one" />
  </unix:password_state>

</def-group>

--
Rodolfo

--
Rodolfo Martínez

On Tue, May 31, 2016 at 5:43 PM, Rodolfo Martínez 
<[email protected]<mailto:[email protected]>> wrote:
Hi List,

After many hours playing with SSG and OpenSCAP and not able to do what
I want I need some help.

Forgive me if I use SCAP or OpenSCAP terms incorrectly, I am new to
SSG and I am still getting familiar.

The following OVAL test searches for system accounts (UID < 500) in
/etc/at.allow (I am showing just the relevant parts of
RHEL/5/input/oval/at_system_accounts.xml to explain my problem):

<criteria>
  <criterion test_ref="test_at_system_accounts_at_allow" />
</criteria>

<unix:password_test check="all" check_existence="none_exist"
comment="Testing system accounts in /etc/at.allow"
id="test_at_system_accounts_at_allow" version="1">
  <unix:object object_ref="object_at_system_accounts_at_allow" />
</unix:password_test>

<unix:password_object id="object_at_system_accounts_at_allow" version="1">
  <unix:username operation="equals"
var_ref="var_at_system_accounts_allow_list" var_check="at least one"
datatype="string" />
  <filter action="include">state_at_system_accounts_at_allow_uid</filter>
</unix:password_object>

<local_variable id="var_at_system_accounts_allow_list"
comment="Accounts Allowed" datatype="string" version="1">
  <object_component item_field="subexpression"
object_ref="object_at_system_accounts_allow_list" />
</local_variable>

<ind:textfilecontent54_object comment="/etc/at.allow"
id="object_at_system_accounts_allow_list" version="1">
  <ind:filepath>/etc/at.allow</ind:filepath>
  <ind:pattern operation="pattern match">^(.*)$</ind:pattern>
  <ind:instance operation="greater than or equal"
datatype="int">0</ind:instance>
</ind:textfilecontent54_object>

<unix:password_state id="state_at_system_accounts_at_allow_uid" version="1">
  <unix:user_id datatype="int" operation="less than">500</unix:user_id>
</unix:password_state>


The test above gets the users information from the sources specified
in NSS (/etc/nsswitch.conf) which is correct, however I want to create
a version that uses /etc/passwd directly. Why? We have many
(thousands?) of RHEL 5 based servers with LDAP integration, and many
(thousands?) of accounts in the LDAP servers.

Simple tests like RHEL/5/input/oval/at_system_accounts.xml and
RHEL/5/input/oval/cron_system_accounts.xml can take hours to run
because they retrieve *all* users information from the LDAP servers
and they do it *for each entry* in /etc/at.allow and /etc/cron.allow.
Also, if we run OpenSCAP (oscap) at the same time in a few servers
they hit the LDAP servers really bad.

I have been trying to replace password_test and password_object by
textfilecontent54_test and textfilecontent54_object without any luck.
If you want, I can share my at_system_accounts.xml file that I thought
it was going to work.

I would really appreciate any help or hint?


Regards
--
Rodolfo Martínez


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