What is Common Criteria?
Common Criteria (CC) is an international standard (ISO/IEC 15408) for certifying computer security software. Using Protection Profiles, computer systems can be secured to certain levels that meet requirements laid out by the Common Criteria. Established by governments, the Common Criteria treaty has been signed by 17 countries, and each country recognizes the other’s certifications.
In the U.S., Common Criteria is handled by the National Information Assurance Partnership (NIAP). Other countries have their own CC authorities. Each authority certifies CC labs, which do the actual work of evaluating products. Once certified by the authority, based on the evidence from the lab and the vendor, that certification is recognized globally.
Your certification is given a particular assurance level which, roughly speaking, represents the strength of the certification. Confidence is higher at a level EAL4 than at EAL2 for a certification. Attention is usually given to the assurance level, instead of what, specifically, you’re being assured of, which is the protection profiles.
CC certification represents a very specific set of software and hardware configurations. Software versions and hardware model and version is important as differences will break the certification.
How does the Common Criteria work?
The Common Criteria authority in each country creates a set of expectations for particular kinds of software: operating systems, firewalls, and so on. Those expections are called Protection Profiles. Vendors, like Red Hat, then work with a third-party lab to document how we meet the Protection Profile. A Target of Evaluation (TOE) is created which is all the specific hardware and software that’s being evaluated. Months are then spent in the lab getting the package ready for submission. This state is known as “in evaluation”.
Once the package is complete, it is submitted to the relevant authority. Once the authority reviews and approves the package the product becomes “Common Criteria certified” for that target.
Why does Red Hat need or want Common Criteria?
Common Criteria is mandatory for software used within the US Government and other countries’ government systems. Other industries in the United States may also require Common Criteria. Because it is important to our customers, Red Hat spends the time and energy to meet these standards.
What Red Hat products are Common Criteria certified?
Currently, Red Hat Enterprise Linux (RHEL) 5.x and 6.x meet Common Criteria in various versions. Also, Red Hat’s JBoss Enterprise Application Platform 5 is certified in various versions. It should be noted that while Fedora and CentOS operating systems are related to RHEL, they are not CC certified. The Common Criteria Portal provides information on what specific versions of a product are certified and to what level. Red Hat also provides a listing of all certifications and accreditation of our products.
Are minor releases of RHEL certified?
When a minor release, or a bug fix, or a security issue arises, most customers will want to patch their systems to remain secure against the latest threats. Technically, this means falling out of compliance. For most systems, the agency’s Certifying Authority (CA) requires these updates as a matter of basic security measures. It is already understood that this breaks CC.
Connecting Common Criteria evaluation to a specific minor versions is difficult, at best, for a couple of reasons:
First, the certifications will never line up with a particular minor version exactly. A RHEL minor version is, after all, just a convenient waypoint for what is actually a constant stream of updates. The CC target, for example, began with RHEL 6.2, but the evaluated configuration will inevitably end up having packages updated from their 6.2 versions. In the case of FIPS, the certifications aren’t tied to a RHEL version at all, but to the version of the certified package. So OpenSSH server version 5.3p1-70.el6 is certified, no matter which minor RHEL version you happen to be using.
This leads to the second reason. Customers have, in the past, forced programs to stay on hopelessly outdated and unpatched systems only because they want to see /etc/redhat-release match the CC documentation exactly. Policies like this ignore the possibility that a certified package could exist in RHEL 6.2, 6.3, 6.4, etc., and the likelihood that subsequent security patches may have been made to the certified package. So we’re discouraging customers from saying “you must use version X.” After all, that’s not how CC was designed to work. We think CC should be treated as a starting point or baseline on which a program can conduct a sensible patching and errata strategy.
Can I use a product if it’s “in evaluation”?
Under NSTISSP #11, government customers must prefer products that have been certified using a US-approved protection profile. Failing that, you can use something certified under another profile. Failing that, you must ensure that the product is in evaluation.
Red Hat has successfully completed many Common Criteria processes so “in evaluation” is less uncertain than it might sound. When a product is “in evaluation”, the confidence level is high that certification will be awarded. We work with our customers and their CAs and DAAs to help provide information they need to make a decision on C&A packages that are up for review.
I’m worried about the timing of the certification. I need to deploy today!
Red Hat makes it as easy as possible for customers to use the version of Red Hat Enterprise Linux that they’re comfortable with. A subscription lets you use any version of the product as long as you have a current subscription. So you can buy a subscription today, deploy a currently certified version, and move to a more recent version once it’s certified–at no additional cost.
Why can’t I find your certification on the NIAP website?
Red Hat Enterprise Linux 6 was certified by BSI under OS Protection Profile at EAL4+. This is equivalent to certifying under NIAP under the Common Criteria mutual recognition treaties. More information on mutual recognition can be found on the CCRA web site. That site includes a list of the member countries that recognize one another’s evaluations.
How can I keep my CC-configured system patched?
A security plugin for the yum update tool allows customers to only install patches that are security fixes. This allows a system to be updated for security issues while not allowing bug fixes or enhancements to be installed. This makes for a more stable system that also meets security update requirements.
To install the security plugin, from a root-authenticated prompt:
# yum install yum-plugin-security
# yum updateinfo
# yum update --security
Once security updates have been added to the system, the CC-evaluated configuration has changed and the system is no longer certified. STIG requirements are now being met, however, and the system is more secure. This is the recommended way of building a system: starting with CC and then patching in accordance with DISA regulations. Consulting the CA and DAA during the system’s C&A process will help establish guidelines and expectations.
You didn’t answer all my questions. Where do I go for more help?
Red Hat Support is available anytime a customer, or potential customer, has a question about a Red Hat product.
Additional Reading
