5 mistakes when implementing Microsoft SOC that cost time and money

Building a Security Operations Center based on Microsoft Sentinel and the Defender ecosystem is an ambitious project – both technologically and organizationally. Sentinel offers powerful capabilities for detection, event correlation, and automated response (SOAR). However, as is often the case with advanced tools, to work properly it must be carefully planned and well structured. Otherwise, instead of supporting the business, the SOC starts to slow it down. And no one wants that. 

If the topic of SOC is still new to you, be sure to check out our article “What is an SOC?” and learn more about our SOC service. And if you already know the basics, we invite you on a short journey through the 5 most common mistakes made when implementing Microsoft SOC – mistakes we regularly observe and that are very easy to make.

We believe this reading will help you avoid them – after all, it’s better to learn from others’ mistakes than from your own! 

At first, everything looks harmless. One business unitn – one workspace. Another department – another workspace. And then another. And another. As a result, after a few months a problem emerges: there are too many workspaces, data is scattered, and event correlation starts to resemble a puzzle with several missing pieces. 

On top of that come rising data storage and transfer costs, as well as complex permission management. Sounds familiar? 

We know a better way! At Euvic, we apply the “as few as possible, but done wisely” approach – meaning a centralized workspace model, well-thought-out governance, and retention aligned with regulations such as NIS2 or DORA. 

It is worth knowing that in many organizations, a central workspace with logical data separation works better than splitting the environment into several or even a dozen smaller ones. 

“Let’s log everything; we’ll filter it later if needed.” This sentence sounds a bit like “quick, before we realize it makes no sense.” In practice, it means an avalanche of data, an avalanche of costs, and… an avalanche of alerts. In such noise, truly important signals simply get lost. 

In 2024 and 2025, we observed a clear trend – SIEM log storage costs could account for even more than half of the IT security budget. That’s why sometimes less really does mean more – especially if “less” means “smarter.” 

First, we select what truly has analytical value: identity logs, endpoint logs, access gateways, or critical systems. The rest only comes later, when we know why it is needed and that it is truly necessary. 

It is worth remembering that logs no one analyzes and that do not support detection are, in practice, just a form of archiving – a very expensive form of archiving. 

Out-of-the-box Sentinel rules are a great starting point. But only a starting point. Environments differ, so if we leave the rules “as they are,” alert fatigue quickly sets in – the system is constantly shouting, and analysts simply stop reacting. 

These are not isolated cases – in many SOCs, as much as 40–60% of alerts are false positives. That is why mature teams operate in a cycle: analysis → tuning → validation → repeat. 

Each adjustment reduces noise and increases detection accuracy. And that means faster response times and fewer sleepless nights. Sounds fair, right? That’s exactly why rule tuning is not an optional “nice-to-have.” It is the foundation of an effective SOC. 

This is one of those mistakes that happens “quietly.” The agent works? It works. So why update it? 

Meanwhile, old versions of agents and connectors mean incomplete telemetry and inconsistent data, and sometimes even complete interruptions in log delivery. Add architectural changes – such as the transition from MMA to AMA – and suddenly it turns out that the SOC is losing visibility exactly where it is needed most. 

Interestingly, in mature organizations, versioning of agents and connectors is part of governance, not an “extra task.” It is definitely worth following their example. 

An SOC does not operate in a vacuum. If network, application, DevOps, or IAM teams are not involved in the logging and response process, gaps will always appear. And when an incident occurs, the lack of context means one thing: slower response and greater risk. 

A mature SOC is a cross-departmental process in which the system owner is not “somewhere on the side,” but actively supports analysis and escalation. Unfortunately, a lack of cooperation equals a lack of visibility. And a lack of visibility equals a lack of security. It’s simple – but there are still many companies that fail to see this or simply ignore it. 

We have gathered a few principles that really work – regardless of the size of the organization. 

1. Design the workspace architecture before connecting logs. 
2. Log what has real analytical value. 
3. Remember to tune rules regularly – SOC is a process, not a project. 
4. Update agents and connectors. 
5. Involve system owners from day one. 
6. Measure effectiveness (e.g., MTTD, MTTR, % of false positives). 

A well-designed SOC built on Microsoft Sentinel can significantly reduce detection and response times while optimizing costs. But the key is process and architectural maturity – not just the choice of technology itself. 

 

„Microsoft Sentinel is a powerful platform, but it is not a magic ‘monitor everything’ button. The success of its implementation depends on whether we can combine technology with process, conscious log selection, and a mature SOC operating model. Without this, even the best tools become nothing more than an expensive console for viewing alerts”.