The idea for this article came about a year ago, maybe even a little earlier, when a message appeared in our corporate inbox informing us that we needed to install a new tool, and that tool was SIEM.
That email instantly triggered a new wave of discussions about SIEM, and a new question quickly emerged in our conversations: “Is the company really trying to spy on us?”. This reaction wasn’t surprising, because the unknown has a way of amplifying doubts and fueling speculation. It has been this way throughout history: ancient people attributed lightning and storms to mystical forces or divine anger simply because they had no better explanation. And now, in a regular corporate setting, a new tool can trigger that same reaction, a mix of curiosity and unease, long before anyone understands what it actually does.
And now it’s time to clear up the concerns and take a closer look at what SIEM actually is.
What is SIEM?
So, before we dive into the technical details, what this tool actually collects and analyzes, we need to understand what it is in the first place.
SIEM, or Security Information and Event Management, is an application that collects and analyzes log data to monitor critical activities in an organization. SIEM tools offer real-time monitoring and tracking of security event logs. The data is then used to conduct a thorough analysis of any potential security threat, risk, or vulnerability identified. SIEM tools have many dashboard options, each dashboard option helps cybersecurity specialists manage and monitor organizational data. So, in simple terms, SIEM acts as a central hub where security-related events from different systems are collected, processed, and analyzed. However, currently, SIEM tools require human interaction for analysis of security events.
What SIEM Actually Does
Alright, that all sounded nice, but it still doesn’t answer the main question: what does SIEM actually do?
Let’s break it down. At a high level, SIEM does four things:
- Collects events
- Normalizes and organizes data
- Detects suspicious or harmful activity
- Alerts security teams and helps investigate incidents
Now let’s take a closer look at each part.
SIEM Collects Events
Every system in an organization generates logs: servers, laptops, applications, firewalls, authentication services, cloud platforms - all.
SIEM acts as a central collector. It gathers:
- login attempts,
- system changes,
- network activity,
- application behavior,
- security alerts from other tools.
These signals are useless in isolation, but together they give context.
SIEM Normalizes and Organizes the Data
Each system logs events differently. One says “authentication failed,” another reports a “login error,” and a third system might only record an error code - all referring to the exact same thing. SIEM translates this chaos into a unified format so analysts (and automated rules) can actually work with it.
SIEM Detects Suspicious Activity
Here’s where SIEM earns its place in cybersecurity.
It correlates different events and looks for patterns such as:
- too many failed logins in a short time,
- access from an unusual location,
- abnormal data transfers,
- unexpected privilege escalations,
- behavior deviation from the user’s normal pattern.
One event means nothing, but a chain of events can mean an attack.
SIEM Alerts and Supports Investigations
When SIEM detects something suspicious, it generates an alert:
- for the security team (SOC),
- for automated response systems,
- or for further analysis.
And if an incident actually happens, SIEM becomes the main tool for reconstructing what occurred: who did what, when, from where, and how.
- Hold on, hold on! Didn’t you just say that employees were asked to install SIEM on their laptops? Based on what you’ve described so far, it might sound like the employees themselves would be doing the monitoring and analysis.
- So let’s clear that up. What we were actually asked to install wasn’t SIEM itself, but a SIEM agent - a small program that sends the necessary logs from employee devices to the central SIEM system. That’s it. The agent doesn’t analyze anything on its own; it simply collects relevant security events and forwards them for monitoring, correlation, and vulnerability detection.
Types of SIEM by Purpose
Although SIEM as a class solves the same core problem of collecting, correlating and analyzing security events, different systems vary in their focus, architecture and intended use cases. SIEM solutions are generally divided into the following categories:
Traditional SIEM
Early generations of SIEM systems focused primarily on log collection, static correlation based on rules, and meeting compliance requirements. The foundation is manual correlation rules and log search.
Focus: Logging, basic correlation, auditing, compliance.
Key features:
- rule-based analysis
- minimal automation
- limited behavioral analytics
- weak cloud support
- simple architecture but high alert noise Examples: MicroFocus ArcSight, older versions of QRadar, LogRhythm Classic
Next-Gen SIEM
Modern SIEM systems that include machine learning, UEBA, automation, and advanced correlation capabilities. Widely used as part of a full SOC ecosystem.
Focus: Advanced analytics, automated response, enhanced correlation.
Key features:
- UEBA (user and entity behavior analytics)
- ML-based anomaly detection
- tight integration with SOAR
- hybrid support (on-prem and cloud)
- improved threat intelligence context Examples: Splunk Enterprise Security, IBM QRadar (newer versions), Exabeam
Cloud-Native SIEM
SIEM systems built to run entirely in the cloud. They offer scalability, speed, and no need to maintain infrastructure. Often support large or nearly unlimited data retention.
Focus: SaaS architecture, high scalability, cloud integrations.
Key features:
- automatic resource management
- ability to process very large log volumes
- seamless integration with cloud platforms (AWS, Azure, GCP)
- fast correlation and search
- pay-as-you-go pricing model Examples: Microsoft Sentinel, Google Chronicle, Sumo Logic Cloud SIEM
Managed SIEM (for MSSP / Managed SOC)
SIEM solutions designed for service providers who monitor and respond to incidents on behalf of multiple customers. Built with multi-tenancy and SLA-driven workflows in mind.
Focus: Security monitoring as a service, MSSP-friendly features.
Key features:
- multi-tenant architecture
- centralized customer management
- automated response capabilities
- reduced operational load for customers
- preconfigured rules and playbooks Examples: AT&T USM (AlienVault), LogRhythm, Blumira
Open-Source SIEM
Systems built on open-source technologies that often require substantial customization. Popular with smaller teams, labs, and technical groups that want flexibility and control.
Focus: Flexibility, accessibility, customization without licensing fees.
Key features:
- free or open-core model
- requires significant configuration
- suitable for DevOps and SecOps experimentation
- strong community support
- flexible but not always enterprise-grade Examples: Wazuh, Elastic SIEM (partially open-core), OSSIM
A little more... (TOP 5 SIEM tools)
We have covered the basics, so it is time to meet the SIEM tools you are most likely to encounter in the real world.
Splunk Enterprise Security
The luxury sports car of SIEM tools.
Incredibly fast, extremely powerful and capable of almost anything… as long as your budget survives.
If a company has massive log volumes and money to spare, Splunk fits perfectly.
In short: "I can do anything. Just pay me."
2) IBM QRadar
The seasoned senior analyst who sees everything and forgets nothing.
It does not need flashy interfaces. It simply gets the job done.
Its event correlation capabilities outperform many newer SIEM products.
In short: "I know exactly what happened, and I have the flows to prove it."
3) Microsoft Sentinel
The SIEM for anyone living in the Microsoft ecosystem.
Easy to start with, cloud friendly and perfectly integrated with Microsoft tools.
Modern, automated and scalable as your organization grows.
In short: "If it is in Azure, I have already integrated with it."
4) Google Chronicle
The Big Data monster on steroids.
It works incredibly fast and stores almost unlimited data without blinking.
If you produce billions of events per day, Chronicle simply says: "So what?"
In short: "Oh, you have a lot of logs? Cute."
5) Elastic SIEM (Elastic Security)
The DevOps favorite: flexible, affordable and endlessly customizable.
It can do a lot if you know how to set it up. But it requires hands-on work, patience and sometimes late-night troubleshooting.
Perfect for those who like tailoring tools to their exact needs.
In short: "I can be anything you want, but you will configure me yourself."
Why Organizations Use SIEM
Companies rely on SIEM for several key reasons:
- Early detection of cyberattacks SIEM can catch signs of intrusions before serious damage occurs.
- Understanding what’s happening in the infrastructure Without SIEM, logs are scattered and unmanageable.
- Protecting sensitive data and accounts It identifies abnormal behavior that could indicate insider threats or compromised credentials.
- Compliance with security and privacy regulations Many standards (GDPR, PCI DSS, ISO 27001, SOC2) require monitoring and log retention - SIEM does exactly that.
- Efficient investigations and audits When something goes wrong, SIEM helps understand where, how, and why.
Final Thoughts: No, the Company Isn’t Spying on You
So, no - the company is not reading our messages (at least not in mine, and definitely not through a SIEM tool), not tracking how many minutes we spend making coffee, and not secretly watching our screens to see what we’re doing. What the company is doing is making sure that no one else gets access to our corporate devices while we’re busy doing our jobs.
In reality, SIEM is far less dramatic than many imagine. It doesn’t spy on employees; it protects the organization from suspicious activity, compromised accounts, and potentially serious incidents. It notices patterns that humans might miss, helps security teams react faster, and ensures that the tools we rely on every day stay safe and trustworthy.
If anything, SIEM’s role is closer to that of a quiet, overworked night guard: it doesn’t care what you typed in Slack - it only cares if someone tries to log in as you from the other side of the world at 3 a.m.
So the next time an email arrives asking you to install another “mysterious security tool” remember: it’s not about watching you - it’s about watching your back.
Talk soon…
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