Many organizations moving to the cloud make the same mistake: they treat it as “just another datacenter.” At first glance, the workloads look familiar — virtual machines, databases, storage. But beneath the surface, the security model is fundamentally different.
If you approach the cloud with an on-premises mindset, you’re setting yourself up for breaches, misconfigurations, and sleepless nights. Here’s why cloud security is not just a lift-and-shift of your old security practices — it’s a whole new game.
The Perimeter is Dead
- On-Prem: Security relied on firewalls, network segmentation, and the idea of a “trusted” internal network. Servers sat behind layers of protection, accessible only through controlled entry points.
- Cloud: The moment you spin up a resource, it’s potentially internet accessible. Storage buckets, web apps, APIs — all are designed for connectivity. The perimeter isn’t a firewall anymore; it’s your cloud configuration.
Example: A file server on-prem is hidden behind your firewall. An S3 bucket in AWS, if misconfigured, can be browsed by the entire world.
Identity is the New Perimeter
In the cloud, who you are (or more importantly, what permissions your identity has) is more critical than where you connect from.
- On-prem, attackers often escalate privileges by exploiting machines and moving laterally.
- In the cloud, stealing a set of API keys or abusing an over-permissive IAM role can give an attacker instant access to an entire environment.
Here’s a concrete example:
In the past, if an IAM user had broad S3 permissions (like s3:* or s3: ListAllMyBuckets), they could enumerate and sometimes even access S3 buckets — even if the bucket wasn’t “theirs” and wasn’t public. Misaligned IAM policies and bucket ACLs meant that “locked down” data wasn’t always as secure as teams assumed.
Even though AWS has improved controls (block public access, access analyser, better policy evaluation), the lesson still applies:
If your IAM permissions are too broad, bucket policies won’t save you.
Cloud Anti-Pattern: “Lambda with Admin Policy”
Serverless functions like AWS Lambda are meant to be small, focused, and with least-privilege workloads. But in practice, many organizations just attach the AdministratorAccess policy because:
- “We’ll fix permissions later.”
- “It’s easier to debug when it has full access.”
- “It’s just a small function, what’s the risk?”
- “AWS Lambda functions have permissions?”
The risk is enormous. If an attacker exploits a vulnerable Lambda (via insecure inputs, dependencies, or CI/CD compromise), they don’t just control that one function — they control your whole AWS account.
It’s the cloud equivalent of running every microservice on-prem as Domain Admin.
Ephemerality and Automation
On-prem servers are long-lived. Once deployed, they’re patched and maintained for years.
In the cloud, infrastructure is ephemeral: servers spin up and down in minutes, containers live for seconds, and deployments happen through Infrastructure as Code (IaC).
This agility is great for innovation, but a nightmare for manual security processes. If you’re relying on quarterly audits or ticket-based change approvals, you’ll always be behind. Cloud security requires continuous monitoring and automated guardrails.
The Shared Responsibility Model
Perhaps the most misunderstood concept in cloud security:
- On-prem: You own everything, so it’s on you to secure everything.
- Cloud: Depending on your cloud service model, the responsibility of securing the technology stack and other aspects such as hardware, networking, datacenter is delegated to the cloud service provider. However, if something goes wrong with your data, you (the customer) are ultimately held accountable because you are the data owner, you define safeguarding rules and policies, and you chose to whom to delegate the responsibility of securing your data.
This is where breaches happen. Many still assume “AWS secures S3,” but AWS only secures the servers and means to running S3, not your bucket permissions. That’s on you.
Visibility and Logging
On-prem environments typically rely on network taps, syslog exports, and SIEM correlation.
In the cloud, visibility is service driven. You need to enable and centralize:
- AWS CloudTrail for API calls.
- Azure Monitor/Defender for activity tracking.
- GCP Audit Logs for governance.
If you’re not ingesting and protecting these logs, attackers can operate in the shadows — and you’ll have little forensic evidence to respond with.
Expanded Attack Surface
With on-prem, the attack surface was predictable: servers, endpoints, and applications exposed through VPNs or DMZs.
In the cloud, every managed service (databases, serverless functions, APIs, storage, and queues) comes with its own security model. Misconfigurations are common because the ecosystem evolves faster than most security teams can keep up.
Example: An overly permissive serverless function trigger could allow attackers to inject code that exfiltrates sensitive data — without touching a single VM.
Compliance ≠ Security
Here’s a dangerous myth: “We passed our audit, so we’re secure.”
On-prem, compliance is often mapped closely to security practices. In the cloud, the two are drifting apart. It’s possible to be compliant while still leaving wide-open holes.
Passing SOC 2 or ISO 27001 won’t protect you from an attacker exploiting an IAM role with *:* permissions. Compliance frameworks can lag years behind cloud innovation — attackers don’t. Conclusion: Rethink, Don’t Lift-and-Shift.
How Curios Helps
Curios bridges the gap between compliance and security by mapping your real cloud risks to compliance frameworks. This means you can demonstrate compliance and prove you’re closing actual attack vectors, not just checking boxes.
Curios helps you make the mindset shift by:
- Replacing perimeter-based assumptions with configuration-aware monitoring.
- Elevating identity as the first line of defense.
- Automating security checks so you keep pace with ephemeral infrastructure.
- Providing visibility, context, and guidance that keep compliance aligned with real-world security.
With Curios, cloud security isn’t just different — it’s manageable, scalable, proactive, and cost-effective.