Navigating the security landscape across the migration lifecycle is essential to safeguard operations and avoid costly breaches. Ensure a secure cloud migration with expert tips on data protection, access management, and post-migration audits.
A QUICK SUMMARY – FOR THE BUSY ONES
Plan and encrypt before you move
Validate the technical and financial feasibility of migration. Encrypt all sensitive data in transit and use secure VPN protocols like WireGuard for connectivity.
Control access and monitor actively during migration
Limit exposure through least privilege access and monitor activities using tools like CloudWatch and IaC scanners to detect misconfigurations early.
Clean up and fortify post-migration
Ensure secure deletion of old data, conduct security audits and penetration tests, validate disaster recovery setups, and update security policies and documentation.
Scroll down to get the full scoop - including hard-earned lessons, favorite tools, and insider tips picked up from real migration projects.
TABLE OF CONTENTS
As a CTO or Head of Engineering, you’re no stranger to the weighty responsibility of keeping your business running smoothly – especially during cloud migration. It’s not just about shifting data and applications; it’s about making sure everything stays secure and protected from potential breaches along the way. I know there’s no one-size-fits-all approach, as every company, system, and set of regulations is different.
In this article, I’ll share some practical tips on how to prepare for a smooth migration and keep your data secure before, during, and after the process.
Here are the main steps and considerations that I believe all companies must be aware of when planning their cloud migration security strategy.
When I’m involved in a cloud migration project, the very first thing I and the team usually check for is whether there are any vendor lock-ins. This means looking at whether we're tied to a specific solution that can’t be easily transferred elsewhere. Sometimes, we discover that the current setup simply isn’t portable; we’d have to build something from scratch to start working with the new system.
So, in my experience, if you’re a business considering migration, the first step is always about answering the question: “Can we migrate at all?”
Beyond that, we also look into potential migration costs. We assess whether those costs will eventually pay off in the long run. For example, if we’re currently storing data in something like AWS S3, we’re charged for every bit of data we move. So, if we've stored a large volume of data, transferring it elsewhere could be really expensive.
We must also verify which approach we want to choose, because each Cloud Provider provides special services for migrations. For example, AWS offers Snowball/Snowmobile, which are used for transferring huge datasets. Using the right tools and services for your project can cut the costs.
To sum up, at this stage, it's all about evaluating whether the switch is technically possible and whether it makes financial sense.
Expert tip: First check, if you can migrate all the data – from a technical and financial standpoint.
We have to make sure that all data, such as files and databases, is properly encrypted or secured. This is important because if anyone gains access to unencrypted data, it could result in a serious security breach.
We also need to confirm whether we can set up a secure, encrypted connection between the old and new cloud providers, and what the costs would be. If possible, we can use the Canary Release strategy to gradually shift data and workloads to the new environment, reducing risk and minimizing potential disruptions. To make this approach work effectively, we’ll need to establish a secure and reliable network connection between the existing and new environments. To do this, we can use a VPN, and we highly recommend tools based on WireGuard, which has worked well for us in the past.
Expert tip: Make sure that all sensitive data is encrypted during migration and check that both cloud providers support secure, encrypted connections. Using a reliable VPN like WireGuard can simplify the process and enhance security.
First, check what specialists there are on your team and ensure your budget can support the necessary expertise for specific areas of the migration. This will guide you in making an important decision: whether to choose Infrastructure as Service (IaaS), Platform as a Service (PaaS), or a hybrid solution.
The right choice largely depends on your team's skills and how you prefer to manage the system. If you go with Infrastructure as a Service (IaaS), you get more control over infrastructure costs since you lease servers and manage them yourself, while the provider handles things like hardware maintenance, power, connectivity and basic required security like limited physical access to infrastructure, securing the network, and so on.
This option is great for fixed costs but does require a skilled team and enough budget.
Platform as a Service (PaaS) shifts more responsibility to the provider. It delivers enterprise-grade solutions aligned with industry standards, equipped with built-in monitoring, backup, and recovery tools, and backed by high SLA guarantees for reliability and uptime.
A hybrid approach is becoming more popular – and it’s my personal favorite. Using this approach, you can combine PaaS and IaaS. For example, you might use a managed Kubernetes cluster like AWS Auto EKS, while managing the underlying nodes through IaC. This approach gives you more cost control and reduces the complexity of managing the cluster.
Take Home Depot as an example – they operate over 2,000 edge devices on their own infrastructure but manage them centrally using a platform-as-a-service model. With PaaS, you can potentially manage infrastructure with a smaller internal team, but you’ll face higher costs – especially early in the migration. However, over time, switching to annual billing can bring savings of up to 70%. A solid cloud migration security strategy can also help ensure your systems are protected throughout the process.
No matter how you set up your cloud environment, you need to decide who’s in charge of managing it. That could be a full internal team, or an outside partner on a fixed monthly contract, which often makes budgeting easier.
Cloud providers like AWS, Azure, and Google Cloud work on a shared responsibility model.
That means that – on top of their Infrastructure – they take care of maintenance, security, SLA, fulfilling industry standards, and other tools/services that are built by them. That said, while you can primarily focus on running your solution, you’re still responsible for proper configuration and the security of your data.
If you're using IaaS (Infrastructure as a Service), you’re responsible for everything except the physical hardware and its SLA. This means you take on more responsibility for setting up, securing, and maintaining your systems. You’re also responsible for ensuring that any tools or services running on that infrastructure meet all relevant industry standards and compliance requirements.
With PaaS (platform as a service), the provider takes care of more, but you still need to secure your applications and data.
SaaS (software as a service) is a good option if you want delegate as much responsibility as possible to others. However, a SaaS-based approach has its limits. For example, lets take SaaS for finances – taxes can start limiting how many responsibilities for security and maintenance are on your side. This option offers the most coverage – the provider handles most of the security – but you’re still responsible for how users access and use the platform.
So, before migrating or scaling in the cloud, it’s smart to review the shared responsibility model and make sure the right security measures are in place, i.e., using either the provider’s tools or trusted third-party solutions.
These choices also affect your costs. IaaS often includes things like data transfer and bandwidth. PaaS, on the other hand, may charge for every bit of traffic. There was a well-known case where a major Polish e-commerce brand ran a marketing campaign without adjusting their cloud setup. The sudden spike in traffic drove costs through the roof, and their platform couldn’t keep up.
Expert tip: Don’t treat cloud migration and responsibilities as a purely technical decision. Knowing which party is responsible for which part of security – and at which price – will help you avoid unpleasant surprises when traffic spikes.
Speaking about cloud security best practices would be incomplete without mentioning team-level permission and access levels.
When it comes to cloud migration security, at the highest level, you must decide exactly who gets access to what type of data. This is a multi-tier subject, as it’s not simply about introducing different clearance levels depending on the team’s seniority or project involvement levels.
You must take into account the specifics of the product or service you’re offering, database context, and even industry. For instance, you can’t give just “any” developer access to financial records. Those who should have it are people with the right expertise and awareness of legal and regulatory obligations. When choosing a provider, compliance is key. We must ensure it meets all necessary standards, like GDPR in Europe or upcoming data regulations in the U.S., and that they offer infrastructure in appropriate geographic locations to meet these requirements.
Apart from the above, you can also decide to limit access to the infrastructure itself to just a handful of authorized admins or software team members.
We can set things up so that developer access is limited – they can deploy their work with predefined tools like Argo CD, where they can view logs, monitor applications, and check the status of deployments. But they won’t get direct access to the infrastructure itself.
Using GitOps approach combined with Infrastructure As Code approach secures that any changes must be reviewed by authorized team members. Once approved, it will enter the production environment.
Expert tip: Limit access to live/production code to prevent not only code defects, but also as a measure of securing your infrastructure.
I also strongly encourage you to have a complete picture of vulnerability risks before you begin migrating. You can use vulnerability scanners like Qualys or Nessus – the best choice depends on your infrastructure and individual use case. These tools help identify not only how many issues there are, but also decide which vulnerabilities need to be patched before the migration, and which ones can be tackled during the move.
These tools typically assign severity scores. If something is rated very high, we usually want to fix it immediately – unless we know the issue will be resolved automatically by migrating to a more secure setup.
This brings me to a scenario I encountered on a project. A client used an Infrastructure as a Service provider that offered disk storage, but as default data wasn't encrypted at all. The client stored data on them assuming everything was secure. In reality, anyone who gained access could simply copy the contents. So, before starting the migration, we prioritized fixing this issue by adding encryption first. Only then did we move forward with migrating to the new provider. This allowed us to close a critical security gap before the migration began.
I’m not really talking about obvious things like using TLS or SSL – that's a given. It’s more about the fact that when we’re moving large volumes of data, we need to think about how we’re actually transferring it. Are we sending it through VPN tunnels? Or are we encrypting the data beforehand and then decrypting it once it reaches the other end (for example, using Borgmatic or similar solutions)? That layer of security is crucial, especially during large-scale migrations. Implementing cloud migration security best practices ensures that sensitive data remains protected throughout the process.
When it comes to migration monitoring, I’d actually combine it with the normal process we’re already preparing and implementing for our solutions. Whether it’s something more straightforward, like using CloudWatch, where you can configure alerts so that the system can automatically inform you whenever anything goes wrong – this ties into the scanning and preparation process, we discussed earlier. We already know the potential cloud migration security risks, and we also determine which tools will be used for scanning.
This is essentially the missing piece where we have a security scanning process in place. Standard tools delivered by Cloud providers allow us to monitor what's happening, but how we interpret the data is a whole different story. In fact, this should be integrated with serviceability. Ideally, we should start monitoring and collecting basic logs from our vendor’s platform, but also incorporate additional scanning tools, such as static code analysis or Infrastructure as Code scanning. For example, if we’re writing Terraform scripts, we can scan them for security issues before applying them to the new infrastructure.
At this stage of the migration, we’re already scanning our solutions, checking for issues like outdated Docker images or unencrypted data before transferring it.
We’ve already touched on these points earlier, as they are part of the migration process. These are general principles, but people often forget them. A common mistake during migrations is that someone migrates their data, but then grants full access rights without thinking. This happens all the time, especially in migration scenarios.
So, it’s important to briefly refer back to this topic. Often, when clients come to us for support, they lack the necessary knowledge and, unfortunately, grant far too many permissions to improper users. A common mistake in AWS, for example, is migrating under the root account instead of creating separate sub-accounts for specific services, tools, or departments and using IAM roles to manage access. Even worse, we frequently see clients sharing between too many employees access to the root account itself – a much bigger risk than simply running services under it. This highlights why clear access and security policies are essential for everything you build and manage.
Aside from knowing that things can go wrong during a migration – and that’s completely normal – we always need to have a backup plan. What happens if something doesn’t go as expected? How can we roll things back? How do we restore the critical parts of the system to keep things running smoothly if needed?
This brings us to an important point, you must know what the critical elements of your system that absolutely must function are. For example, if your company relies heavily on something like a helpdesk, then you know you must ensure communication with clients – those calling in – continues without disruption.
And beyond that, you need to identify what your key business functions are. You have to protect those and make sure you can quickly recover them if anything goes wrong.
Make sure the data is properly cleaned before canceling any subscriptions. Some companies forget to do this, which makes their data retrievable (especially if they used HDD-s).
When moving from on-premise servers or a data center to the cloud, the service provider is supposed to wipe the drives. However, we cannot always be sure that wiping data was done according to standards, and are wiped in an unretrievable manner. There's a risk that someone could recover sensitive data from old drives, even after they’ve been wiped. I've seen it happen – people buy decommissioned servers and are able to recover data from Hard Drives.
That’s why it’s essential to plan for a post-migration cleanup. Once everything is running smoothly on the new infrastructure, securely erase the old one using proper data destruction tools. Only then you should cancel the service.
Expert tip: Secure data destruction after migration; it’s as important as the migration itself.
To ensure your new cloud environment is secure, it’s important to run both vulnerability assessments and penetration tests. Vulnerability scans can identify known weaknesses, but pen tests (or "ethical hacking") take it a step further by mimicking real-world attacks.
These tests help you see how well your security holds up under pressure. They can either be run internally or externally (the latter especially if you're in a regulated industry like banking or pharma, where third-party security audits are often required by law). These experts dig deeper, evaluate your security, and suggest ways to improve.
Another cloud security best practice that should make it into your post-migration security checks is using honeypots. These are intentionally vulnerable decoy systems that lure attackers in. When suspicious activity is detected, it’s redirected to these honeypots, letting you test your monitoring tools and security setup and see how well they catch threats. It’s a controlled way to track potential attackers and learn from their tactics without compromising your real systems.
Naturally, don’t forget about tools that check your certificates, subdomains, and DNS records. For example, if you operate a subdomain which includes the name of the tool (like: wireguard.domain.com), the domain itself would hold the name of the tool. This makes it prone to automated attacks, which target well-known shortcomings of the tool you’re using. But, if the certificate is issued to a wildcard (*.domain.com) and DNS records are similarly set up, then we hide information on the tools we’re using. Paying attention to things like these can help you spot vulnerabilities early, so you’re not caught off guard later.
Automatic updates can be a double-edged sword. On one hand, they’re great because many teams simply don’t prioritize security patches the way they should. On the other, they could introduce issues, especially if the automatic updates conflict with the current configuration.
What’s the middle ground? Most teams opt for security scanning tools that continuously monitor for vulnerabilities. When an issue is flagged, they assess the risk and decide when and how to patch it – making sure it won’t disrupt the infrastructure.
I want to underline here that it's smart to assume that every tool or service is potentially vulnerable. If it doesn’t need to be public-facing, then don’t expose it to the internet. Instead, hide it behind a VPN.
That way, only your internal team (or selected clients) can access it, and only via secure VPN connections. If a service isn’t public, it’s not visible to threat actors, which means it’s much less likely to be scanned or targeted in the first place.
If a vulnerability does appear here, you’re not under immediate pressure to patch it within hours. But if the service is exposed to the web, you’ll need to act fast.
Backups are fundamental, that’s why I’ve mentioned them multiple times throughout this piece. They need to be prepared in advance, and after migration, we must ensure backups are set up correctly. This is also a post-migration process, where we additionally verify if our Disaster Recovery process is working.
For example, we test a portion of our system to check if we can recover from any failures. It’s part of the ongoing maintenance process – periodically, we randomly check our recovery processes to ensure they still work. Infrastructure changes can affect disaster recovery procedures. Sometimes, clients think they’re prepared, but when disaster strikes, they find out that they were only prepared for an older version from months ago. So, during migration, we check these processes, and post-migration, we validate them again to ensure everything is functioning.
If regular security reminders haven't been implemented in the company as part of an ongoing cycle, it’s important to introduce that. This cycle should remind employees about various threats and security practices.
Make sure your staff are aware of the fact that there are scripts (hidden behind unknown links or pdf-s) that can be unintentionally run and encrypt data or open a backdoor to the system/network - those can reveal your company’s information like your IP, system update status. All this could help to create vector attacks on your Infrastructure. This can happen through an infected employee laptop – even when your tools are behind a VPN. It’s also good to include XDR and SIEM solutions like Wazuh, which can help in the fast identification of incidents and speed up your response to them.
This involves defining roles, establishing VPNs, and deciding which systems are securely hidden behind firewalls. Additionally, a key step at the end of the migration process would be conducting a re-inventory and verifying the architecture. It’s crucial to check if everything aligns with the original plan. During migration, some aspects may change, so it's necessary to update documentation on what has been implemented, how it's secured, what is exposed publicly, and what isn’t. This serves as a final audit that ensures everything is in line with the initial security plan.
If we plan to make infrastructure changes later, it’s easier to refer to this updated documentation. It's essential to make sure that, even if the migration timeline spans months or even years for large infrastructures, we can track any modifications made during the process.
I’d also suggest keeping a decision log throughout the migration process. This helps document why certain choices were made and provides valuable context for future reference. Each entry should include the background of the decision, the challenges faced, and the reasons behind the chosen solution.
Having this log makes it much easier to revisit past decisions, especially if a similar issue comes up down the line. It can save time for you or anyone else who might be investigating a related problem in the future. Instead of starting from scratch, they can review the decision log to understand what was done before and why, and apply those insights to the current situation.
Cloud migration – choose a safe path for your business
The steps I discussed illustrate that there’s never a one-size-fits-all approach to cloud migration security. There are probably multiple cloud migration security challenges and questions you’ll come across, which is why it’s worth working with the right partner who’ll safely guide the way.
At Brainhub, we have years of experience with building and managing cloud-based solutions for companies – reach out to learn how we could help you with yours.
Our promise
Every year, Brainhub helps founders, leaders and software engineers make smart tech decisions. We earn that trust by openly sharing our insights based on practical software engineering experience.
Authors
Dariusz Luber is a dynamic and versatile Solution Architect & DevOps Engineer at Brainhub.
Software development enthusiast with 7 years of professional experience in the tech industry. Experienced in outsourcing market analysis, with a special focus on nearshoring. In the meantime, our expert in explaining tech, business, and digital topics in an accessible way. Writer and translator after hours.
Dariusz Luber is a dynamic and versatile Solution Architect & DevOps Engineer at Brainhub.
Software development enthusiast with 7 years of professional experience in the tech industry. Experienced in outsourcing market analysis, with a special focus on nearshoring. In the meantime, our expert in explaining tech, business, and digital topics in an accessible way. Writer and translator after hours.
Read next
Popular this month
previous article in this collection
It's the first one.
