Certified: The Security+ Prepcast

When it comes to cybersecurity, detection is just as important as prevention. Even the strongest defenses can be bypassed. When that happens, you need eyes on the system—watching, recording, and alerting you to suspicious behavior. That is where monitoring comes into play. Monitoring computing resources is a core practice that allows organizations to maintain visibility into what is happening across systems, applications, and infrastructure. In this episode, we explore how real-time monitoring supports threat detection, performance management, and incident response across three layers: systems, applications, and infrastructure.
We begin with systems monitoring. This involves keeping track of the health, performance, and behavior of individual computing systems such as servers, desktops, and cloud-based instances. System monitoring tools observe key metrics like CPU usage, memory consumption, disk activity, process behavior, and logins. The goal is to detect performance issues, operational disruptions, and indicators of compromise.
Real-time monitoring helps security teams detect threats that may otherwise go unnoticed. For example, a sudden spike in processor usage could indicate a crypto-mining attack. Excessive disk activity might signal ransomware encrypting files. Unusual outbound network traffic could suggest a compromised system exfiltrating data. These changes in behavior often precede or accompany an active security incident. Without monitoring, such events might remain hidden until damage has already occurred.
Let’s consider a practical example. A system administrator notices an alert from a monitoring dashboard showing that a critical server is using an abnormally high amount of memory and has experienced a dramatic increase in outgoing traffic. Upon investigation, the team discovers a rogue process transmitting data to an unfamiliar address. Because the system was being monitored in real time, the breach is contained quickly—preventing data loss and limiting damage. Without monitoring, the issue could have persisted for days or weeks.
System monitoring is also important for operational resilience. It helps teams identify failing hardware, misbehaving services, or software conflicts that could lead to downtime. Security depends on stability, and early detection of system issues gives teams time to respond before users are impacted or security is compromised.
Next, let’s look at application monitoring. Applications are where business happens. Whether it is a website, a database, or an internal workflow tool, applications contain the logic and data that drive operations. Monitoring applications involves tracking logs, observing runtime behavior, and watching for performance anomalies that may signal a security threat or operational failure.
Application logs capture a wealth of valuable information. These logs record user actions, authentication attempts, system errors, and transaction history. Monitoring tools can parse these logs in real time, alerting administrators to failed logins, suspicious inputs, or unauthorized access attempts. This visibility is especially important in web applications, where attacks such as Structured Query Language injection, cross-site scripting, or privilege escalation may leave digital fingerprints in the logs.
Runtime behavior monitoring goes a step further. It watches what the application actually does while running. This includes which resources it accesses, how long it takes to respond, and whether it interacts with unexpected components. If an application suddenly starts making external network calls, loading unknown libraries, or spawning new processes, that may indicate compromise. Monitoring tools can alert administrators or even automatically quarantine affected services based on predefined rules.
Let’s look at a real-world example. A company’s human resources portal is being monitored for application behavior and user activity. The monitoring tool detects repeated login failures from a single Internet Protocol address, followed by a successful login using an administrator account. It then observes the download of several large employee data files. These alerts prompt the security team to investigate. They quickly discover that the admin credentials had been stolen through phishing, and the attacker was attempting to exfiltrate sensitive information. Because of application monitoring, the attack was detected and stopped early.
In another case, an e-commerce company tracks page load times and error logs in real time. A sudden spike in errors reveals a Structured Query Language injection attempt that is causing the database to fail. Developers respond immediately, patch the flaw, and restore functionality. The system not only avoids compromise but also benefits from enhanced logging that prevents similar issues in the future.
Now let’s turn to infrastructure monitoring. This involves observing the devices and systems that support communication and connectivity across the organization. Think of switches, routers, firewalls, and wireless access points. Infrastructure monitoring tools track uptime, configuration changes, traffic flow, bandwidth usage, and device health. They help ensure that the network is not only running—but also secure.
Changes in network behavior often signal attacks in progress. A sudden increase in bandwidth usage could mean a distributed denial of service attack. A router configuration change made outside of normal maintenance hours could suggest unauthorized access. A firewall that suddenly opens unexpected ports may be exposing systems to the internet. Monitoring these devices in real time enables rapid detection and response.
Let’s explore a case study. A security team monitors a core switch that connects multiple business units. Late one evening, the system logs an unauthorized configuration change followed by an unusual increase in internal traffic. The change was made using stolen credentials, and the attacker was attempting to reroute data through a compromised host. Because of the monitoring system’s alert, the network team rolls back the change and initiates an investigation. The breach is contained, and additional controls are put in place to prevent future unauthorized changes.
Another example comes from a hospital using network monitoring to oversee wireless access points. When an unknown device begins broadcasting near the surgical unit, the monitoring tool detects the new signal, compares it to a known list of approved devices, and flags it as rogue. The device is investigated and removed before any patient data is compromised. Monitoring infrastructure helps organizations stay ahead of attackers who might exploit weak or unobserved network segments.
Infrastructure monitoring also supports long-term security by creating a detailed baseline of normal activity. By knowing what typical usage looks like, deviations become easier to spot. Over time, trends can be analyzed to improve capacity planning, optimize configurations, and identify latent vulnerabilities before they are exploited.
To tie it all together, monitoring across systems, applications, and infrastructure gives organizations the visibility they need to stay secure. Systems monitoring focuses on resource usage and operational behavior. Application monitoring captures logs and runtime data that reveal misuse or attacks. Infrastructure monitoring keeps the underlying network and communication layers under continuous watch. When used together, these tools create a layered, intelligent defense that goes beyond prevention and enables rapid detection, response, and recovery.
As you prepare for the Security Plus exam, be ready to recognize the types of monitoring and the kinds of alerts they generate. Understand how monitoring fits into incident response, risk management, and ongoing security operations. Expect scenario questions that ask you to analyze a monitoring alert, determine its significance, or recommend a next step. Review terms like log aggregation, event correlation, anomaly detection, and configuration drift—they are all part of effective monitoring.