Complexity is the price of flexibility. And nowhere is that more apparent than in multi cloud security.
According to Flexera’s 2026 State of the Cloud Report, multi cloud adoption has risen by 2 percentage points year over year. However, out of the 14% operating exclusively in multi cloud, some organisations end up with complex cloud environments by circumstance rather than by design. (1)
Whether enterprises adopt multi cloud strategies intentionally or not, the most important question to ask is whether the security strategy has kept pace with the infrastructure decisions that led there.
For organisations to reap multi cloud benefits, security can’t be retrofitted. It must be built in from the ground up.
What is multi cloud (multicloud)?
The multi cloud definition is straightforward: using services from more than one cloud provider simultaneously. Rather than relying on a single vendor for all hosting, storage, and compute needs, organisations distribute workloads across two or more platforms, for example using both Azure and Amazon Web Services (AWS). For example, this could be done to optimise workload placement or as a failover between clouds.
Multi cloud differs from hybrid cloud, which combines an on-premises environment with a public cloud. Multi cloud is broader – multiple public clouds, not necessarily integrated at the architecture level.
Multi cloud examples: common use cases
Multi cloud adoption rarely follows a single path. Four scenarios account for most of it:
1 Operational technology (OT) and Information technology (IT) separation
Organisations running operational technology (industrial control systems, monitoring grids, energy infrastructure) alongside corporate IT often find that different platforms suit different workload types. A single cloud rarely serves both well without introducing latency, compliance issues, or capability gaps.
2 Mergers and acquisitions
When a business acquires another, it inherits that organisation’s existing technology environment. Immediate migration isn’t always feasible – so the combined business runs across multiple clouds, sometimes indefinitely. The complexity arrives with the deal, not by design.
3 Failover and disaster recovery
Spreading workloads across two providers builds resilience. When one platform goes down, the other keeps services running. For businesses with high availability requirements, this level of physical protection is a deliberate architectural decision.
4 Siloed applications across separate clouds
According to Flexera’s report, this is the most common multi cloud architecture – 59% of organisations run separate applications in separate clouds. Rather than a unified multi cloud strategy, different teams or business units adopt the platforms that best suit their workloads, resulting in a fragmented environment that grows organically over time.
Multi cloud security challenges
Managing security across multiple cloud environments is fundamentally different to managing a single platform. The challenges are distinct, and they compound quickly.
- Interoperability and expanded attack surface. Every additional platform introduces new connection points – APIs, applications, integrations, identity systems. Each one is a potential entry point. The more environments an organisation connects, the wider the attack surface grows. Managing API security across two or more platforms demands specialised expertise that many teams don’t have in-house.
- Patching complexity. Different cloud platforms run on different patching cadences and standards. Across two or more platforms – often running different operating systems and workload types – the administrative burden multiplies fast. Verizon’s 2024 Data Breach Investigations Report found that 50% of known exploited vulnerabilities remain unpatched after 55 days. In a multi cloud environment, closing that window takes deliberate, sustained effort.
- Tool sprawl. Each platform ships with its own native security tooling. Organisations layer additional tools on top to fill gaps or gain visibility. The result – multiple tools meeting the same business function – drives up administrative overhead, introduces inconsistency, and creates more surface area for things to go wrong.
- Monitoring overload. Monitoring overload. As platforms multiply, so do event streams. Systems calibrated for a single environment struggle to keep up, leaving blind spots where threats can move undetected.
What good multi cloud security looks like
Good multi cloud security starts with the right architecture. Security design needs to reflect how a business operates – its risk appetite, environment, and industry. It’s not one-size-fits-all.
That means network segmentation that follows business functions, not just technical boundaries. It means choosing platforms based on genuine capability fit, and resisting the pull towards standardising on a single tool stack when environments have different requirements. Best-of-breed only works when it’s chosen with intent, not pieced together over time.
Designing security in from day one is what separates genuinely resilient environments from those that appear managed. Embedding security into Infrastructure-as-Code, with automated patching and built-in vulnerability remediation from the outset – not bolted on later – is what makes the difference.
The case for multi cloud managed services
Technology should actively support business outcomes, not just sit behind them. This puts pressure on internal teams.
Most are still carrying a heavy operational load, leaving limited capacity to build and maintain the depth of security a multi cloud environment demands. In-house models increase the likelihood that critical security functions are missed or mishandled:
- Missing emerging threats in time
- Delayed or ineffective mitigation
- Data theft and data loss going unnoticed
- Single point of failure in people
- Fragmented monitoring
Multi cloud managed services change that. Instead of one team trying to cover everything, organisations gain access to shared security capability – from SOC and SIEM to automated monitoring and response – delivered at a scale that’s difficult to replicate in-house. Continuous 24/7 coverage, AI-driven automation, and dedicated security engineering move the model from reactive oversight to proactive defence.
The cost dynamic shifts as well. Building and sustaining multi cloud security internally requires significant and ongoing investment in people, tooling, and processes. For many organisations, maintaining that level of capability over time is difficult, particularly as the threat landscape continues to evolve.
A stronger multi cloud security posture starts here
Multi cloud environments aren’t inherently insecure. But they demand a more deliberate, sophisticated approach to security than most organisations can deliver on their own.
The businesses that get it right build the right architecture from the outset – security embedded at every layer, with the operational discipline to sustain it over time.
Advent One’s cloud services practice is built on exactly that foundation. With over 25 years of managed services experience, Advent One brings cloud-agnostic capabilities across hyperscale cloud environments and multi cloud architecture and platform engineering, with security woven into every stage from architecture through to ongoing operations.
Ready to close the gaps in your multi cloud environment? Talk to our expert team today.
(1) https://info.flexera.com/CM-REPORT-State-of-the-Cloud