Audit your systems for security compliance with OpenSCAP

OpenSCAP logoIntroduction to (Open)SCAP

SCAP stands for Security Content Automation Protocol. It is an open standard which defines methods for security policy compliance, vulnerability management and measurement etc. This article focuses on the operating system compliance part of SCAP.

It comes originally from the US National Institute of Standards and Technology (NIST) to provide a way for US government agencies to audit its systems for regulatory compliance.

OpenSCAP is a NIST validated open source implementation of SCAP.

Why should I make use of OpenSCAP anyway?

Lot of people will ask this question to them self, in particular System Administrators and Engineers since they are not IT Security Officers.

The simple answer is that you just sit down with the IT Security Officer once and define which systems need to be compliant to what regulatory, With OpenSCAP you can always ensure the systems are configured according the the policy (or policies).

Organizations that need to be compliant according to a official policy will sooner or later facing an external security audit. I experienced that several times, its a nightmare. If you can proof that your systems are scanned regularly with the SCAP standard, you will be very well prepared, an external auditor will not bug you for a long time.

Abbreviations, abbreviations, abbreviations

Its obvious, government agencies love abbreviations ūüėČ Lets explain the two most important ones.


Extensible Configuration Checklist Description Format. This files, i.e. /usr/share/xml/scap/ssg/content/ssg-rhel7-xccdf.xml contain descriptions used for auditing a system against compliance to a policy.

This files are usually included in your distribution and are updated if needed.


Open Vulnerability and Assessment Language. Its used to detect vulnerabilities and patches.

Since vulnerabilities and patches are popping up very quickly they need to be downloaded and distributed to all systems to be audited on a regular base (i.e. daily).

OVAL files can be downloaded as listed below:

Organizations using System Management Tools such as Red Hat Satellite or SUSE Magager will not profit from OVAL patch scans as those products will report which patches have been applied or not by themself. Nevertheless, additional OVAL scans add the benefit of vulnerability scanning regardless of installed patches.

More Abbreviations

More abbreviations and a short description of them can be found here:

OpenSCAP Scap Security Guide (SSG)

There are a lot of regulations out there. Government of some countries releases policies and sometimes SCAP content for some Operating Systems, mostly RHEL and Windows. The SSG Project works on collecting and implementing content for this policies for the operating systems as well as for some other software such as JBoss. Included in the scap-security-guide are the most important US Government and PCI-DSS for RHEL. Only available for Debian at the moment is the content for the French ANSSI DAT-NT28.

The only Linux distributions I’m aware of that provides packages for scap-security-guide are RHEL and Fedora. However, upstream there is some content for more distributions available. I really hope that all important and fine distributions such as SLES, Debian and Ubuntu will jump on the bandwagon.

Regulations covered by OpenSCAP SSG

Here a list of what is available for the most important Linux distributions.

Red Hat Enterprise Linux 7

  • PCI-DSS (Payment Card Industry – Data Security Standard), Commercial – USA
  • C2S (Commercial Cloud Services), Government – USA
  • USGCB/STIG (United States Government Configuration Baseline/Security Technical Implementation Guide), Government – USA
  • CNSSI 1253 (Committee on National Security Systems), Government – USA
  • CJIS (Criminal Justice Information Services), Government – USA

Debian and Ubuntu

Officially there is nothing available. Its is currently under development, see and

As of 2017-03-04 compiling fails.

  • ANSSI DAT-NT28 (Agence nationale de la s√©curit√© des syst√®mes d’information), Government – France

Suse Linux Entrprise Server

Suse does not provide the scap-security-guide package and there is no XCCDF content for regulatory compliance checks delivered by Suse. However, some basic tests are available. It is not clear if Suse has some plans to join the scap-security-guide community, would be nice to see that. SLES customers can open a support case at and ask for enhancement.

Using SCAP content without scap-security-guide

You can make use of SCAP content without the OpenSCAP security guide. Its rather complex and not covered in this article.

Installing the required packages


[root@server ~]# yum -y install scap-security-guide

All required dependencies will be installed as well

Debian and Ubuntu

root@ubuntu:~# aptitude install python-openscap

All required dependencies will be installed as well


sles12sp2:~ # zypper install openscap openscap-content openscap-extra-probes openscap-utils

All required dependencies will be installed as well

Tailoring profiles

For most users it is probably too much to secure its systems according to military standards which includes turning off USB support and the like.

The most important civil regulatory by far is PCI-DSS. Each company handling kind of Credit- or Debitcard data must obey the current standard. As of writing this article this is version 3.2.

PCI-DSS is a de-facto standard in Enterprise Linux environments.

Of course it makes sense for all kind of companies to secure its systems. On systems which are not exposed security policies can be more relaxed.

Also good to know is that some tests simply do not apply to your system. I.e. if you are using a centralized identity management software such as Redhat IdM with IPA or Microsoft Active Directory then the central instance will take care about the password policies, not the particular system to be audited.

Installation of the SCAP Workbench

The Scap Workbench is available in RHEL to be installed by yum, a binary for Windows and Mac OS is available as well. Needless to say that the source code is available.



In the following examples, we disable the check for AIDE.

SCAP-Workbench Screencast

SCAP-Workbench Screencast

You can save the tailoring file as a single XML file or even better safe it as an RPM for easy distribution to all your systems.


The usage is the same on all tested Linux distributions. Be aware, XCCDF scanning makes no sense w/o any SCAP content. If your distribution does not provide you the necessary data, 3rd party providers may.

RHEL 7 comes with the scap-workbench which is GUI that allows you to scan the local or remote systems via SSH. The scap-workbench is a nice tool to scan a handful of servers manually but not to scan a whole zoo of servers.

You also can scan your systems with the CLI on the host itself. Kind of automation can be done with i.e with Ansible.

Manual Scan

The oscap info command gives you an overview which profiles are available.

[root@server ~]# oscap info /usr/share/xml/scap/ssg/content/ssg-rhel7-xccdf.xml
Document type: XCCDF Checklist
Checklist version: 1.1
Imported: 2017-02-14T13:33:08
Status: draft
Generated: 2017-02-14
Resolved: true
Referenced check files:
[root@server ~]# 

Lets choose pci-dss and start a scan:

[root@server ~]# oscap xccdf eval --profile pci-dss --results scan.xml --report scan.html /usr/share/xml/scap/ssg/content/ssg-rhel7-xccdf.xml
Title   Ensure Red Hat GPG Key Installed
Rule    ensure_redhat_gpgkey_installed
Ident   CCE-26957-1
Result  pass

Title   Ensure gpgcheck Enabled In Main Yum Configuration
Rule    ensure_gpgcheck_globally_activated
Ident   CCE-26989-4
Result  pass
[Lot of Output immited]

The parameter –results saves the result in a HTML file.

Automated scanning with Redhat Satellite 6

Users of Redhat Satellite 6 can schedule scans of large server farms. The screenshots shows you how compliance tests can be presented to a IT Security Officer.

Compliance Report

Compliance Overview

The Compliance report shows a overview of hosts and a brief look at how many test have been failed.

Compliance Report Detail view

Compliance Report Detail view

The Compliance report detail shows which test have been failed. It also provides a description of each topic.

Host details

Host details

The detail view of a host shows that this host is not compliant. In this case, security errata must be applied and the host must be reconfigured to get compliant to the security policy.

Alternatives to OpenSCAP

There are a few alternatives to OpenSCAP as listed by the NIST’s Security Content Automation Protocol Validated Products.

Further reading

Cross distribution system management with Spacewalk

In a perfect world, all systems in a data centre are running the same Linux operating system, a homogeneous system landscape. In real life things are working differently. Windows systems are out of focus in this post, lets concentrate on Linux systems.

Most companies with a large Linux base are either RHEL shops or using SLES. A lot of RHEL users have some SLES systems running and so are SLES users running some RHEL systems. Some companies have additional systems running Debian.

How to handle those heterogeneous system landscapes? Those real world scenarios? Lets assume a company runs 500 RHEL systems, 20 SLES systems and some 10 Debian systems.

At the moment, for the base software management subscription such Linux users are spending a lot of money for RHN Satellite and SUSE Manager. Additionally there are per-system costs for management, provisioning and other modules. The Debian systems are handled manually. A lot of additional costs for a few out-of-strategy systems.

The solution is Spacewalk, the upstream project of the RHN Satellite which is at the same time the upstream for the recently released SUSE Manager. While SUSE offers support for RHEL systems, Red Hat does not (yet) offer support for SLES systems for RHN Satellite.

In Spacewalk Version 1.4 code contributions from SUSE are included and a student at Brno University of Technology contributed Debian support for Spacewalk as part of his master thesis.

While the support for SUSE is already quite stable, the Debian related code still have some rough edges. No wonder, SUSE is using RPM for its packaging wile Debian has its own packaging system. This makes it much easier for SUSE to get Spacewalk ready for its distribution.

At the moment, one can call the Debian support still as experimental, but the goal for the Spacewalk project is to have it fully functional in future releases.

The goal should be that both of the management system from the major enterprise Linux vendors, Red Hat and SUSE should support each others distribution for its Spacewalk based products. Debian is a niche player in the enterprise Linux environment and should also be supported by both products, RHN Satellite and SUSE manager. Nobody does expected to get system support for those distributions by the competing distribution, but having support for the management of it.

Further readings:
Registering Clients
Deb support in Spacewalk

Have fun!

Ubuntu 10.04 LTS released

End of April 2010, Ubuntu 10.04 was released. As always it is based on Debian’s Testing-Release. Canonical “stabilizes” the testing tree of Debian and adds its own look.

This time, Ubuntu radically changed its look. From my point of view it looks ugly, very ugly. Strange colors, low contrasts in menus, orange icons in Nautilus… window buttons on the left side… At the end of the day an usability-horror.

Under the hood Ubuntu is a very stable distribution with recent software. Ubuntu 10.04 is a LTS (Long Term Support) version and is thus suited as a enterprise server. Support for the server variant of Ubuntu is five years. Ubuntu is – like Debian – capable to upgrade to a new major release w/o service interruption.


You “can” mirror Debian and Ubuntu repositories locally but it is difficult if you to not like to mirror all architectures available. Unfortunately there is (AFAIK) no software available such as Spacewalk/RHN Satellite to manage your servers.

The best method is to allow each single system installed to talk directly or via proxy to the mirror servers. This is a nightmare for firewall administrators.

To my knowledge there is no convenient way to install Ubuntu over the net. There are rumors that spacewalk and cobbler is going to get Debian/Ubuntu support at some time.


Debian and thus Ubuntu has an evidence to be reliable. This also  seems to be true for the current release 10.04. The software came from Debians testing repository but was stabilized during months. Canonical (The sponsor of Ubuntu) has a reputation for its quality management. To use Ubuntu as a server operating system is sane.


As a desktop operating system I’ll avoid Ubuntu, since the usability is focused on dummy-users and not professional Linux users. For server usage you need to ask yourself about your needs. If you are operating Oracle DB’s or other commercial applications you probably want install Red Hat Enterprise Linux (RHEL). For a web server Ununtu is very well suited, even better than RHEL. In two years there will be another LTS variant available and you are free to upgrade online. Reliability is very good, manageability is poor, especially when used in larger companies.

In short: Ubuntu for web servers, RHEL/CentOS for other servers.

As always: Feedback is welcome…

Have fun!

Ready to upstart?


It is time to replace the aged SysV init system with someting better

At the time when¬† SysV init (pronounced “System five”) appeared, hardware configurations have been quite static, no hot plug and similar fancy stuff.

SysV init is started after the kernel is loaded. The init process reads /etc/inittab and walks trough the runcontrol script and runlevels. This sequential walk-trough takes most of the time when booting a modern Unix system.

Upstart follows another approach: Starting daemons and services in parallel and event driven.  This will speed up the boot process beyond expectations.

A very nice feature of upstart is: All processes will be started in background, no more blocking of the boot process trough hanging run control scripts!

If a service unexpectedly dies, it will be respawned  automatically up to a configurable limit in times per period.

Upstart is event-driven, a event can be e.g. plugging in new hardware which ends up starting the needed service for it. There are also plans to replace cron and atd with upstart since this are basically time-triggered events. The developers also thinking about replacing the inetd, since a network connection can be considered as a event.


Since most of the software out there do not natively support upstart yet, transition methods are needed for a smooth transition from SysV init to upstart. Traditional SysV run control scrips are fully supported, even distributions slowly switch to the event/job model of upstart. E.g. one of the first distributions switched to upstart was Ubuntu 6.10, and now with Ubuntu 9.10 – three years later – they begin to ship its distribution with the first native upstart scripts.

Splitting Unix systems apart

Years ago there only have been two init systems: SysV init and BSD init, a sysadmin was comfortable to use them on whatever system. Now there are SysV init, Upstart from Ubuntu, lauchd from Apple, SMF (System Management Facility) from Sun Microsystems and possibly others. All of this SysV init replacements are working differently,¬† different commands, different architecture… This makes the job of a sysadmin not easier when managing a heterogeneous system landscape.

Linux distributions stay together

The good news: On the Linux side it looks like Upstart will be the future standard for system initialization, no balkanization of the Linux Landscape so far.

Linux Distribution with upstart

The following distributions are already shipping upstart:

  • Ubuntu
  • Debian
  • Fedora
  • Others?

Since Fedora 11 and 12 will be the upstream for the upcomming RHEL6 distribution it is most likely that RHEL6 comes with upstart. At openSUSE there are some discussions (see for details). Maybe there is a chance for openSUSE 11.3 and later on SLES12.

Further readings:

Upstart web site:
Wikipedia article:

Have fun!