Outdated security information and event management systems (SIEMs) are costing your business more than you might think. Here we take a deep dive into the hidden costs of legacy SIEMs and how a modern, next-generation SIEM platform can eliminate them.
Legacy SIEM vs Modern SIEM
What’s the Difference Between Legacy and Modern SIEMs?
SIEMs first emerged around the turn of the century with the aim of centralizing and correlating logs to more efficiently respond to cyberattacks. This allowed security teams to detect and respond to breaches in real time, rather than react blindly after the damage had been done. As such, SIEMs brought with them a huge improvement in the efficiency of security operations centers (SOCs) and the protection they could provide.
Like any technology, SIEMs are constantly evolving. And in an area like cyber security, this evolution is essential for keeping up with ever-changing threats.
However, rather than the steady evolution you might expect, in recent years SIEMs have undergone nothing short of a revolution. The explosion in data creation, combined with the growing accessibility of AI has caused the threat landscape to evolve quickly – and SIEMs have had no choice but to keep up.
Such a fundamental shift in the way SIEMs operate has created a clear divide between old (legacy) SIEMs and new (modern) SIEMS.
Learn more about the competitive SIEM market in our exclusive whitepaper SIEM Wars: A Battle for Dominance in Security Information and Event Management.
Why are Many Organizations Still Using Legacy SIEMs?
There are many reasons why firms are stuck on legacy SIEMs. These could be a lack of resources, a lack of skills required for such a complicated migration procedure, or simply a reluctance to embrace change. However, often the most prominent reason we hear is cost.
In many cases, CFOs and other non-technical executives find it hard to justify the initial capital expenditure involved in migrating their legacy SIEM to a modern SIEM platform.
However, when you look beyond the visible bill and instead consider the total cost of ownership (TCO) of a legacy SIEM vs a modern SIEM, the benefits of SIEM migration are clear.
The Visible Bill vs TCO
What Makes up the Visible Cost of Owning a SIEM?
The visible cost of owning a SIEM consists of several key elements, which are all easily quantifiable. These include the cost of a license, surcharges, support and maintenance, and any add-on modules that are required.
Beyond these visible costs, however, there are a number of other factors in play that are harder to put an exact figure against.
What Makes up the TCO of Owning a SIEM?
The TCO of a legacy SIEM can be significantly higher than what is immediately attributable to the platform – identified above as the visible cost. However, because SIEMs have always represented a vast improvement on earlier iterations – and indeed the firewall-only protection of the 1990s – costs have simply been accepted as a saving.
The difference with today’s landscape is that modern SIEMs offer a the next-level of efficiency, and that has a huge knock-on effect on TCO.
In this article, we break these down into six hidden-cost areas, namely: infrastructure, staffing, efficiency, compliance, vendor lock-in, and opportunity cost.
The Hidden Costs
1. Infrastructure & Scalability
What’s the Problem with Legacy SIEM Infrastructure?
Your on-premises (on-prem) hardware-based SIEM is fine for the environment it was built for. The problem is, that environment looks very different now – and it’s changing constantly.
Hardware-based SIEMs are restricted by the capabilities of the hardware they use, so they lack the flexibility to scale and evolve with the threat.
Why do you Need to Scale up your SIEM?
Scaling up your SIEM is essential for a number of reasons, and they all come down to data.
As the threat landscape evolves, attacks are becoming more complex. This means SIEMs are capturing, processing, and storing more logs, which requires bigger drives and more powerful processors.
Furthermore, requirements for long-term (cold) storage are increasing. The UK’s National Cyber Security Centre (NCSC) recommends that your most important logs should be stored for at least six months, while Article 10.5.1 of the Payment Card Industry Data Security Standard (PCI-DSS), now requires companies to hold data for 12 months. This increases the pressure on legacy hardware with limited capabilities.
Why is Legacy SIEM Hard to Scale?
Legacy SIEMs can be hard to scale because expanding their capabilities means sourcing, installing, and configuring additional hardware. This takes time, effort, and expertise, but most importantly – money. Hardware doesn’t come cheap.
Modern cloud-native SIEMs, on the other hand, are elastic in nature, meaning they can grow and shrink on demand, automatically, with minimal cost and effort.
2. Staffing & Skills Drain
What is the Labor Cost of Legacy SIEMS?
Legacy SIEMs are static and manual in nature, which means they demand more resource to run than their modern successors. When you also consider the size of the global cybersecurity workforce gap is now 4.8 million – up 19% YoY – finding the staff to fulfil these roles is becoming increasingly difficult.
Why are Legacy SIEMs more Resource Dependent?
Legacy SIEMs can tie up engineers with essential processes like tuning scripts, writing parsers, developing correlation rules, and performing manual triage. This is exacerbated by higher false positive rates from less capable legacy technology.
Modern cloud-based SIEMs benefit from machine learning (ML) technology that automates these processes, freeing up valuable time and resource.
This economic impact study from Forrester and Microsoft, for example, found that migrating to a modern SIEM could potentially enable the redeployment of 50% of infrastructure services staff and 16% of legacy SIEM specialists.
What is The Knock-on Effect on Staff Retention?
With less-capable legacy SIEMs, engineers often waste valuable hours fighting the technology, rather than hunting threats. When combined with the skills gap, the additional stress loaded onto already overstretched teams can lead to burnout and attrition. In fact, in one study of cybersecurity leaders, 93% of those looking to leave their roles said stress and job demands were the main drivers.
3. Efficiency
Why is SIEM Efficiency so Important?
According to a Pao Alto Networks study, in 2020 the average SIEM received 11,000 alerts every day and, due to lack of resource, 28% of those were never addressed. This is a problem that hasn’t gone away, with Splunk’s State of Security 2025 report finding that 47% of respondents face alerting issues and 59% spend too much time maintaining tools and workflows.
Much of this valuable time is spent manually performing tasks that are fully automated in modern SIEM platforms. Indeed, the same Slunk study found that 28% spend too much time normalizing data and 31% feel they have outdated or inadequate processes.
What is the Cost of High-Noise Alerts?
The cost of high-noise alerts for legacy SIEMs without ML and automation can be huge. For example, in this article, Elastic claims that its automated workflow is triaging and closing over 3,000 alerts per day – the equivalent workload of 94 full time employees.
4. Compliance Exposure
Why can Legacy SIEMS be Less Compliant with Regulations?
Legacy SIEMs utilize on-prem infrastructure, which was not built for today’s cloud-based threat landscape and can leave cloud accounts unmonitored. These blind spots often lead to dangerous gaps in security that attackers can exploit and auditors will penalize.
Additionally, on-prem storage limitations mean that logs are often not kept long enough to satisfy regulators in the event of a breach.
How Much can you be Fined for a Non-Compliant SIEM?
There are a number of different regulations in place that impose significant fines on those who are not meeting requirements. Examples include NIS2, which can impose fines of up to €10m or 2% of turnover on essential entities and GDPR, which can demand up to €20m or 4% of turnover.
These enormous figures become more likely the longer you leave the blind spots. Furthermore, every incident that goes undetected extends dwell time, which can increase breach-response time and potentially raise the costs of resolving an attack.
5. Vendor Lock-In
Why are Legacy SIEMs more Susceptible to Vendor Lock-in?
Legacy SIEMs are based on intricate manual tuning and vendor-specific languages, along with custom parsers and correlation rules. The more intricate these become, the more labor-intensive it is to change to a new platform.
Combine all this complexity with early cancellation penalties and the resulting cost can make annual license-fee uplifts seem like the lesser of two evils.
Why are Modern SIEMs Different?
Modern SIEMs are cloud-native, benefit from advanced automation, and most importantly, use vendor-neutral, open formats such as the Open Cybersecurity Schema Framework (OCSF).
This means that there are no on-prem hardware restrictions on storage and no time-consuming rewrites. Using a modern SIEM makes it much easier and cheaper to walk away if a better tool comes along.
6 . Opportunity Cost & Reduced Innovation
Why is your Legacy SIEM Slowing Innovation?
According to the previously mentioned Forrester and Microsoft report, discontinuing a legacy SIEM could potentially reduce TCO by 44% as a result of lowering ingestion, reducing licensing fees, and eliminating hardware costs.
Consider this in the context of your budget and think how much money you could reallocate to areas of innovation that will improve efficiency even further.
What Opportunities are Being Lost?
In addition to freed-up budget, your team will also benefit from freed-up time. For example, this study found that since adopting a unified platform approach, 53% of respondents spent less time maintaining tools.
That means your analysts can spend more of their days proactively hunting threats or working on strategic initiatives such as AI-assisted threat-hunting, zero-trust architecture, and other initiatives that can give you the edge.
Conclusion
It’s clear that legacy SIEMs present a broad range of hidden costs that, while not immediately obvious, together can add up to a significant total cost of ownership.
The key takeaway here is that these hidden costs are optional, not inevitable.
Sure, there will be an initial outlay for migrating from a legacy SIEM to a modern SIEM, but the long-term savings will make up for it in droves.
If you’re ready to take the next step, our experienced team can help. We have performed over 100 SIEM migrations for some of the largest organizations in the world.
We are completely vendor agnostic, so if you’re looking for impartial advice, contact our friendly experts for a no-obligation chat.
