A baseline is a known starting point and organizations commonly use secure baselines to provide known starting points for systems. If you’re planning to take the SY0-501 version or the SY0-401 version of the Security+ exam, you should have a basic understanding of baselines and how they can be used in different situations. This includes monitoring the systems for any baseline changes, which is a common security issue.
Here is a sample practice test question:
Q. Network administrators have identified what appears to be malicious traffic coming from an internal computer, but only when no one is logged on to the computer. You suspect the system is infected with malware. It periodically runs an application that attempts to connect to web sites over port 80 with Telnet. After comparing the computer with a list of applications from the master image, you verify this application is very likely the problem. What allowed you to make this determination?
A. Least functionality
B. Sandbox
C. Blacklist
D. Integrity measurements
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.
Secure Operating System Configurations
Most operating systems aren’t secure out of the box. Instead, administrators must take specific steps to secure them. A common method of deploying systems is to create a master image with a secure configuration, and then deploy the image to multiple systems.
A trusted operating system meets a set of predetermined requirements with a heavy emphasis on authentication and authorization. The overall goal of a trusted operating system is to ensure that only authorized personnel can access data based on their permissions. Additionally, a trusted operating system prevents any modifications or movement of data by unauthorized entities. A trusted OS helps prevent malicious software (malware) infections because it prevents malicious or suspicious code from executing.
A trusted OS meets a high level of security requirements imposed by a third party. For example, the Common Criteria for Information Technology Security Evaluation (or simply Common Criteria) includes requirements for a trusted OS. Operating systems that meet these requirements can be certified as trusted operating systems. Also, a trusted OS typically uses the mandatory access control (MAC) model.
Using Master Images
One of the most common methods of deploying systems is with images starting with a master image. An image is a snapshot of a single system that administrators deploy to multiple other systems. Imaging has become an important practice for many organizations because it streamlines deployments while also ensuring they are deployed in a secure manner. The Deploying Systems with Images blog post discusses the overall process of capturing and deploying an image.
Resiliency and Automation Strategies
Resiliency and automation strategies include automation, scripting, and templates and they can help deploy systems securely, and keep them in a secure state. As an example, administrators often use Group Policy in Microsoft domains to automatically check and configure systems. Group Policy provides automated courses of action by applying security and other settings.
Additionally, Microsoft has created several security templates with various levels of security. Administrators can modify these templates to fit their needs, import them into a Group Policy Object (GPO), and then apply them to systems within the domain. Some organizations deploy a master image to all systems, and then use the security templates to automatically apply different security settings to different groups of systems based on their security needs.
Secure Baseline and Integrity Measurements
A baseline is a known starting point and organizations commonly use secure baselines to provide known starting points for systems. One of the primary benefits of secure baselines is that they improve the overall security posture of systems. Weak security configuration is a common security issue, but secure baselines help eliminate this.
The use of baselines works in three steps:
- Initial baseline configuration. Administrators use various tools to deploy systems consistently in a secure state.
- Integrity measurements for baseline deviation. Automated tools monitor the systems for any baseline changes, which is a common security issue. Some tools such as vulnerability scanners monitor the systems and report any changes they detect. Other tools such as Group Policy automatically reconfigure the systems to the baseline settings when they detect changes.
- Remediation. Chapter 5 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide covers network access control (NAC). NAC methods can detect some changes to baseline settings and automatically isolate or quarantine systems in a remediation network. Typically, administrators need to correct the problems in these systems manually.
Remember this
A master image provides a secure starting point for systems. Administrators sometimes create them with templates or with other tools to create a secure baseline. They then use integrity measurements to discover when a system deviates from the baseline.
Q. Network administrators have identified what appears to be malicious traffic coming from an internal computer, but only when no one is logged on to the computer. You suspect the system is infected with malware. It periodically runs an application that attempts to connect to web sites over port 80 with Telnet. After comparing the computer with a list of applications from the master image, you verify this application is very likely the problem. What allowed you to make this determination?
A. Least functionality
B. Sandbox
C. Blacklist
D. Integrity measurements
Answer is D. The master image is the baseline and the administrators performed integrity measurements to identify baseline deviations. By comparing the list of applications in the baseline with the applications running on the suspect computer, you can identify unauthorized applications.
None of the other answers include the troubleshooting steps necessary to discover the problem.
The master image would include only the applications, services, and protocols needed to meet the principle of least functionality.
A sandbox is an isolated area of a system, typically used to test applications.
A blacklist is a list of prohibited applications.
See Chapter 5 of the CompTIA Security+: Get Certified Get Ahead: SY0-501 Study Guide
or
Chapter 6 of the CompTIA Security+: Get Certified Get Ahead: SY0-401 Study Guide
for more information on securing hosts and data.