What is Security Information and Event Management (SIEM)?

Quick Definition: A SIEM is a security platform that analyzes security alerts in real-time. They are crucial for compliance with regulations like HIPAA, GDPR, and CMMC by ensuring proper monitoring, reporting, and threat detection.

If you're here, you're likely trying to make sense of SIEM (Security Information and Event Management) and why it's such a big deal in cybersecurity. That is understandable because it can feel like a pretty complex topic. 

While it's not always explicitly mentioned in regulations or frameworks, like CMMC, many cybersecurity requirements point directly to the functions a SIEM provides—log collection, threat detection, and incident response. 

So, let’s dive into what a SIEM actually is and why it’s essential for protecting your network.

What is SIEM?

Security Information and Event Management (SIEM) is a security platform that provides real-time analysis of security alerts generated by hardware and software systems. SIEM systems are responsible for collecting, storing, and analyzing log and event data from firewalls, routers, servers, and applications, to detect potential security threats and incidents.

You can think of SIEMs as the central nervous system of your security operations, constantly processing and analyzing data from across your network to find and respond to potential threats in real time.

Key Functions of SIEM

SIEMs do a lot of heavy lifting for security teams. Let's take a look at their core functions.

• Log Collection and Aggregation: SIEMs gather log data from different systems, including network devices, security appliances, servers, and applications, and centralize this data for analysis.

• Event Correlation: SIEMs use predefined rules or algorithms to correlate events and detect suspicious activity, such as potential intrusions, malware, or other security incidents.

• Real-Time Monitoring: SIEMs provide continuous, real-time monitoring of an organization’s network and systems to detect threats as they occur.

• Incident Response: By identifying patterns that could indicate security incidents, SIEM systems help security teams respond quickly, investigate the root cause, and minimize damage.

• Threat Detection: SIEMs help identify anomalies, malicious activities, or vulnerabilities that could be exploited.

• Compliance Reporting: SIEMs provide audit trails and reporting capabilities that help organizations meet regulatory compliance requirements, such as those from PCI-DSS, HIPAA, or GDPR.

SIEMs and CMMC: How They Relate 

SIEMs play a crucial role in helping organizations comply with the Cybersecurity Maturity Model Certification (CMMC) by improving their ability to detect, monitor, and respond to security issues in real time. 

CMMC requires organizations to implement cybersecurity practices to protect sensitive information, and SIEMs help by providing centralized log management, automated threat detection, and incident reporting. Within CMMC, once we get to level three, log collection and analysis become crucial. For example, AU.3.048 says you should collect your audit logs into one or more central repositories. That sounds like a SIEM to me.

Then, AU3.051 talks about correlating audit log review, analysis, and report on audit logs collectively. The keyword there is "collectively" because without analyzing all the logs in a centralized manner, you will have difficulty correlating events from various systems. Again, it sounds like a SIEM to me!

So the next question is, what are my options when it comes to a SIEM solution?

3 Options for SIEM Solutions 

You have three options when looking for SIEM solutions: purchase, subscribe, or build. There are advantages and disadvantages to each option based on your budget and requirements.

1. Purchase a Commercial SIEM Solution

Purchasing a commercial SIEM can be hit-and-miss, to be honest. I say this because you have to vet the product and make sure it will do everything you need. After all, once you invest capital into the product, you're stuck with it unless you don't mind wasting money.

You must purchase training and spend the time necessary to train on the product, so your team can efficiently manage the platform. There will also be an annual support agreement to budget for and be careful of limitations of these products, such as limits on the amount of data they will process in a given time period. As your environment grows, you may need to consider the costs of upgrading the SIEM to support the additional data from new systems.

Pros of a Commercial SIEM:

• There are lots of vendors to choose from

• It's less costly than a SIEM service (most of the time)

Cons of a Commercial SIEM:

• Your internal team must manage the system

• You'll need to provide compute resources to host it on

• Training can be expensive and extensive

2. Subscribe to SIEM-as-a-Service

SIEM-as-a-service is the easiest to get up and running. Some benefits include (generally) no up-front costs, as it is a month-to-month operational expenditure. Since this is a hosted service, you won't need to provide compute resources, so you're not looking at any hardware upgrades to support it.

Another nice thing is the vendor team will manage the system and provide you with reports and alerts, which means you won't need the level of training with a commercial SIEM product. The downside is that these services are usually more expensive than a commercial SIEM solution, but that may not be true if you hire personnel to manage a commercial SIEM product.

The last thing to consider is that you're sending log data offsite, so you'll want to ensure you have adequate bandwidth. You'll also want to verify how the vendor stores the data and that they follow security best practices since they are housing some of your sensitive data.

Pros of SIEM-as-a-Service

• You don't need to provide computing resources

• Your internal team doesn't manage the system

Cons of SIEM-as-a-Service

• It's usually the most expensive option

• Added risk by sending your log data off-site

3. Deploy and Manage an Open Source SIEM

An open-source SIEM solution is going to be the most cost-effective SIEM solution. However, you must provide computing resources and people to manage the solution, just as you do with a commercial product. The key to going with open-source is oftentimes convincing executives that it's a sound decision.

To do this, you'll need to find an open-source project that's been around for a while and provides paid support services, preferably with some Service Level Agreement (SLA). With an open-source solution, you need to ensure adequate training is available. This means more than a few online videos from various users but honest-to-goodness training from the product makers.

This way, you are getting the training straight from the horse's mouth and not someone else’s opinion on how it works. Lastly, open-source projects are often more secure than closed-source commercial products because of the number of developers reviewing the code, and that's always a win!

Best Practices for SIEM Implementation

When you're implementing a SIEM, it’s easy to get overwhelmed with all the features and possibilities. But if you focus on best practices, you can set yourself up for success from the start. Here are some key steps to make your SIEM implementation smoother and more effective.

Define Clear Objectives and Use Cases

Before diving in, you must understand what you're trying to achieve with your SIEM. Are you looking for better threat detection? Maybe you're aiming to meet specific compliance requirements. By defining clear objectives and use cases, you can address your organization's unique needs— rather than just adding another piece of tech to your stack.

Ensure Proper Data Collection and Normalization

Your SIEM is only as good as the data it collects, so make sure to include data from every relevant source—firewalls, servers, routers, applications—basically, anything that could be a target for attackers or a source of vulnerability. But it doesn’t stop at collection. The data needs to be normalized, meaning it's transformed into a consistent format that your SIEM can analyze. This step is crucial for detecting threats across different systems.

Regularly Update and Fine-Tune Correlation Rules

The predefined rules your SIEM uses to detect threats will not stay effective forever. Cyber threats evolve, and your environment changes, so it’s important to regularly update and fine-tune these rules to ensure they're still relevant. If you don’t, you risk missing critical alerts or getting swamped with false positives, which can bury the real threats in noise. Set a schedule to review and adjust your correlation rules as needed.

Implement Automation for Incident Response and Remediation

The power of a SIEM isn’t just in identifying threats—it’s in what you do next. Implementing automation for incident response can help you react to threats faster and more efficiently. For example, you can automate processes like isolating compromised systems or blocking suspicious IP addresses. 

This way, you minimize damage while your security team focuses on investigating and resolving the issue.

Train and Educate IT Staff on SIEM Usage and Best Practices

Your IT team should be well-versed in how to operate the system, interpret alerts, and respond to incidents. Investing in training ensures that your team is prepared to maximize the system’s potential and more effectively mitigating security risks. Regular training sessions also help your team stay updated on new SIEM features and industry best practices.

Conclusion 

SIEMs are essential for maintaining security and compliance in an increasingly complex (and risky!) IT environment. For IT professionals, understanding how SIEMs work and why they matter is critical for protecting sensitive data, detecting threats in real time, and responding to incidents before they escalate. 

Whether you're tasked with ensuring regulatory compliance or safeguarding your organization’s network, a SIEM can provide the visibility, automation, and reporting you need to stay one step ahead of cyber threats. 

At the end of the day, mastering SIEM isn’t just about meeting requirements—it’s about equipping your team with the best tools to keep your systems secure and resilient. 

Want to learn more about cybersecurity? Consider our CompTIA Security+ Online Training!