SIEM Alerts Best Practices: Tuning, Examples, and Reducing False Positives

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By: RedLegg Blog

Every day, cyber threat actors look for weaknesses in connected devices, networks, and enterprise systems. While modern cybersecurity tools—especially Security Information and Event Management (SIEM) systems and EDR—help identify threats faster, many teams still struggle to respond effectively.

One major reason? SIEM alert fatigue.

SIEM systems collect and analyze log and event data across your environment, generating alerts when suspicious activity is detected. But when thousands of SIEM alerts are triggered daily, many of them false positives or low-priority events, security teams are left chasing noise. The result is alert fatigue: a state where analysts become desensitized, distracted, or overwhelmed by constant notifications.

The impact is significant. Missed alerts can lead to data breaches, compliance failures, reputational damage, and long-term business disruption. And the longer it takes to detect and act on a real threat, the more damage it can cause.

That’s where SIEM tuning becomes essential. By refining SIEM rules, thresholds, and correlation logic, organizations can reduce alert overload and help teams focus on what truly matters.

In this article, we’ll explore the benefits of tuning your SIEM, highlight actionable SIEM alerts best practices, and share how to reduce alert fatigue while improving response times.

Understanding SIEM Tuning

SIEM systems typically analyze high volumes of data from various threat monitoring and detection solutions deployed across your organization's networks, endpoint devices, enterprise systems and cloud applications.

As a result, your SIEM may churn out a large number of alerts, including some false positives and several minor, inconsequential or irrelevant alerts. You want your SIEM system to operate at peak performance and your security teams to focus on the alerts that matter.

SIEM tuning offers a solution to control the amount of data presented to you, minimizing irrelevant alerts and bringing attention to alerts that are most likely to represent genuine threats in the context of your organization's specific security landscape.

Recent research from the Neustar International Security Council (NISC) shows just how common false positives have become: 43% of organizations say more than 20% of their security alerts are false positives, and 15% report that over half of their alerts are false. The alert volume and fatigue rise as companies invest more in threat intel and monitoring tools. That means more wasted analyst time and a higher chance of missing actual threats

And if you have some basic questions like 'What is SIEM' or 'Why Use a SIEM', we suggest you download our free eBook on SIEM for an overview of how SIEM fits in the grander scheme of cybersecurity.

The Benefits of SIEM Tuning

There are a number of very good reasons to use SIEM tuning:

  • It enhances the accuracy of alerts: Regularly finetuning a SIEM system is essential to improve the accuracy of alerts and increase the chances of detecting targeted threats.
  • It saves time and effort for security teams: SIEM tuning uses automation to cut down on irrelevant or duplicate alerts and filters out false positives. It saves precious time and effort for your IT department or your managed security services provider. 
  • It reduces alert fatigue: When security professionals have to go through thousands of security alerts a day, they can miss a critical alert amidst a host of insignificant ones.
  • It prioritizes the alerts that matter: It also provides context and assigns priority levels to alerts so that your team can focus on the ones that matter and increase the chances of detecting threats early to mitigate the potential damage from cyber attacks.

RedLegg's co-managed SIEM service gives you access to a dedicated team of analysts who understand your security concerns. Our ongoing SIEM monitoring and tuning services with 24x7x365 support help you accomplish your security goals—and leave your team free to move forward with your overall business objectives.

Download our Managed SIEM Service Information Sheet for an overview of our SIEM Service features and benefits and how our Co-Managed SIEM is different from other MSSPs.

Effective Strategies for SIEM Alert Tuning

SIEM systems require ongoing refinements and adjustments to meet the dynamic and ever-evolving needs of your cyber threat landscape.

Let's look at some practical tips to adopt SIEM alert best practices and empower security teams to respond effectively to incidents. 

Refine your rules and alert configurations regularly

The very concept of SIEM tuning is based on customizing generic rules and configuring system settings to align more closely with your organization's specific needs and security goals.

As your network infrastructure and technology stacks change, you must refine and retune SIEM settings to accommodate new endpoints and applications and updated compliance requirements. Remove decommissioned hosts and add new ones as your network footprint changes with time.

Adapt to changing threat landscapes and current risks

Just as your network footprint and technology stacks change, so does the external threat environment. It is vital to understand the current risk vectors for your organization—as they may have changed since you last configured your SIEM—and build new use cases into your SIEM to optimize your security posture.

Update baselines and adjust thresholds 

You have set your SIEM to trigger an alert at a certain level of activity based on your organization's risk tolerance. But as your organization grows and changes, you may have to adjust the thresholds to maintain a balance between genuinely useful alerts and inconsequential ones.

If you are using SOAR (Security Automation, Orchestration, and Response), you will want to update your baselines to avoid false positives.

Customize & optimize event correlation rules

A correlation rule defines a sequence of actions or events in a network that denote an attack pattern. You must regularly optimize these rules to control the number of insignificant SIEM alerts. Finetuning these correlation rules requires a security expert who understands your organization's threat landscape. Work with an analyst from your MSSP or incident response team and set up feedback loops and discussions to review your SIEM alert best practices.

Stay on top of privilege changes for team members

As some employees leave your organization and new ones join in, their access privileges to various resources and their access details will change. It is critical to ensure that privileges are granted according to the level of access needed for each individual to avoid privilege escalation attacks. Additionally, it's a good idea to set up automated notifications to be triggered whenever a user attempts to change or alter these privileges.

Don't leave holes or blind spots

With all the refinements and retuning to weed out false positives and irrelevant alerts, remember to ensure that you don't leave a blindspot—that is—a security gap or vulnerability that lets through a potential attack. Carefully study your SIEM reports to ensure there are no holes in your security.

And finally, always apply patches and updates ASAP

Pay attention to any application updates for the SIEM that have been released. This will help you avoid zero-day attacks that can pass through threat detection solutions.

Following these SIEM alert best practices will streamline your security operations and protect your critical applications, network—and, ultimately, your business interests!

The Role of SIEM in Proactive Security Posture

A properly tuned SIEM system does more than reduce alert fatigue—it strengthens your proactive security posture. When SIEM rules are fine-tuned to prioritize relevant activity and filter out noise, the system becomes a strategic asset rather than a reactive tool.

By correlating log data across your network, cloud services, and endpoints, a well-calibrated SIEM can identify behavioral anomalies, policy violations, and indicators of compromise before they escalate. These early insights are critical for security teams aiming to take action before a minor event turns into a breach.

Instead of drowning in false positives, teams gain visibility into high-fidelity alerts that support early threat containment and smarter decision-making. This shift—from reactive triage to proactive defense—transforms a tuned SIEM from a burden into a force multiplier.

Whether managed in-house or supported by a Managed Security Services Provider (MSSP), a strategic SIEM approach supports broader threat intelligence efforts and improves your organization's ability to detect, respond, and adapt.

Continuous Tuning and Retuning of SIEM Alerts

SIEM tuning is not a one-time task. Rather it is an iterative process that needs regular refinement and validation. 

Whether you handle SIEM in-house or use a Managed Security Services (MSS) solution, it's important to tune and retune your SIEM.

Failing to do so can compromise your incident response capabilities. You risk alert fatigue and you may miss out on early threat detection, leading to a successful attack by a cyber threat actor.

Threats such as ransomware, phishing, and APTs (Advanced Persistent Threats) are constantly evolving. Correlation rules and thresholds you set in your SIEM will soon prove insufficient to deal with current attack vectors. So it its critical to readjust your SIEM settings to stay a step ahead of cyber threat actors and minimize the chances of a malicious breach.

That's why you need a systematic approach to retune and adjust SIEM configurations and settings regularly. 

RedLegg: Implementing Effective SIEM Alert Tuning Practices

Don’t expose your organization to unnecessary risks. Give your SIEM regular tune-ups and take corrective action to ensure your cybersecurity posture is strong. 

Take advantage of RedLegg's free SIEM Architecture Review and get actionable recommendations for SIEM alert best practices and to discuss various aspects of your security perimeter, tools, policies, procedures, and processes.

RedLegg offers a co-managed SIEM service that provides round-the-clock threat monitoring to enhance your organization's security posture.

Reach out to our cybersecurity experts today for more guidelines and recommendations to enhance your SIEM alert tuning efforts.

Get Your Free SIEM Architecture Review