Certified: The Security+ Prepcast

If Domains One through Three are about understanding the principles and design of cybersecurity, then Domain Four is about the actual day-to-day work that keeps systems secure. This is where cybersecurity gets real. Welcome to Security Operations.
Domain Four is the largest domain on the Security Plus exam. It makes up 28 percent of the test—that’s nearly one-third of the total questions. That alone tells you how important this material is, both for the exam and for your career. Whether you want to work in a Security Operations Center, manage a network, or help an organization stay secure over time, this is the knowledge you need.
Security operations is all about what happens after systems are built and deployed. It’s the constant, ongoing effort to monitor, maintain, and protect information systems against threats that evolve by the day. It’s the stuff that never stops—patching, logging, monitoring, responding to alerts, managing identities, and maintaining secure configurations.
Let’s start with what you’ll see in this domain. One major focus is system hardening. That means reducing the attack surface of systems by turning off unnecessary services, removing default accounts, restricting access, and applying secure configurations. A hardened system is one that’s been deliberately stripped of excess features that attackers could exploit. You’ll be expected to know how to apply hardening to different types of devices—like workstations, mobile devices, servers, and cloud services.
Next is patch management. Vulnerabilities are discovered all the time in operating systems, applications, and firmware. Keeping systems updated with the latest security patches is a core operational task. And not just blindly applying updates—you’ll also need to understand change control processes, testing patches before deployment, and maintaining rollback options in case something breaks.
You’ll also dive into asset management. This is about knowing what’s on your network—what devices, what software, what services. You can’t secure what you don’t know about. Asset inventories must be kept current, categorized, and regularly reviewed. That includes tracking lifecycle status so outdated or unsupported systems can be retired or isolated.
Then there’s alerting and monitoring. This is where tools like SIEMs—Security Information and Event Management systems—come into play. A SIEM collects logs from across the environment, analyzes them for patterns, and triggers alerts when something suspicious happens. You’ll be expected to understand how SIEMs work, what kind of data they collect, and how security teams use them to detect incidents.
Related to that is logging and auditing. You’ll need to know which logs matter—like authentication logs, firewall logs, and system event logs—and how they help trace incidents or detect unusual behavior. You’ll also learn about centralized log management, log retention policies, and log integrity—because logs are only useful if they’re accurate, complete, and tamper-proof.
Another core focus is identity and access management, often called IAM. This includes things like multifactor authentication, password policies, account provisioning and deprovisioning, least privilege, and role-based access control. You’ll see scenario questions that describe a set of user requirements, and you’ll need to choose the correct IAM configuration based on security best practices.
Automation and orchestration are also covered in this domain. That means using scripts, tools, and platforms to reduce manual work and enforce consistency. You might automate patch deployment, access reviews, or incident ticketing. You’ll be expected to know what kinds of tasks are good candidates for automation, and what the benefits and potential risks are.
This domain also introduces endpoint protection platforms—things like antivirus, anti-malware, host-based firewalls, and more advanced tools like EDR and XDR. EDR stands for Endpoint Detection and Response. It monitors endpoint behavior, detects threats, and allows security teams to investigate and respond to incidents. XDR—Extended Detection and Response—takes that idea further by combining data from multiple sources like endpoints, networks, and cloud services into one unified system.
Another big area is incident response. You’ll need to understand the steps of the incident response process—preparation, detection, analysis, containment, eradication, and recovery. You’ll see questions that describe a scenario and ask you what to do next, or how to handle a specific type of attack. This isn’t just about theory—it’s about action. What do you do when something goes wrong?
And closely related to that is digital forensics. While you won’t be performing full-scale forensic investigations on the exam, you’ll need to understand the basics. That includes preserving evidence, maintaining chain of custody, and recognizing which data sources are useful for investigations. You’ll also learn about legal considerations and how forensic practices support incident response and compliance.
Let’s make this real with an example. Imagine a financial services company notices unusual outbound traffic from a server that doesn’t normally talk to the internet. The SIEM picks up the anomaly. Logs show connections to a suspicious external IP. The security team isolates the server, pulls logs for forensic review, and starts containment and eradication. This is a classic security operations scenario—and one that could easily be mirrored in a Security Plus exam question.
So how do you prepare for this domain? First, understand that practice is essential. There’s only so much you can absorb by reading or watching videos. You need to interact with the tools—whether that’s in a lab environment, a simulation, or a virtualized setup. Try working with firewall settings, creating user accounts with different permissions, or reviewing logs in a SIEM interface.
Use flashcards to reinforce terminology. Make sure you understand the differences between things like IDS and IPS, EDR and XDR, multifactor and single sign-on. And don’t just memorize definitions—be able to apply them. If a question says, “A user’s account was locked after five failed login attempts,” you should immediately connect that to account lockout policies and brute-force mitigation.
And finally, track your progress across the topics in this domain. Break it down into smaller sections—patching, monitoring, IAM, incident response—and focus on one at a time. This domain is dense, but it’s also full of concrete, real-world knowledge that will serve you well beyond the exam.
From a test perspective, expect lots of scenario-based questions. You’ll need to recognize symptoms of attacks, choose the right response, configure secure settings, and explain why certain tools are used. If a question says “a user downloads a suspicious attachment,” you’ll need to know what logs to check, what alerts to expect, and what action to take next.