At Render, we power over 2.5 million live services, making it easy for developers to deploy and scale their applications. With this extensive experience managing cloud infrastructure, we've seen firsthand the evolving challenges of keeping cloud applications secure.
As the adoption and implementation of cloud applications have become the norm, so too have the cyberthreats targeting these very applications. A modern cloud application will be subjected to many different types of attacks and attack vectors.
Securing a cloud application requires a multilayered approach, including secure identity and access management (IAM), robust encryption principles, a secure software development lifecycle (SSDLC), and continuous monitoring of your environment.
In this article, we'll share best practices for building secure cloud applications. You'll learn specific ways to secure your systems against cyberattacks, including:
- How to adopt a Secure Software Development Life Cycle (SSDLC) to ensure security at every stage of development.
- The importance of implementing robust IAM principles to safeguard access to your cloud resources.
- Techniques for setting up continuous monitoring and logging to detect and respond to potential threats in real time.
Adopting SSDLC: The First Step
The best kind of cloud application vulnerabilities are the ones you find before you deploy to production. SSDLC is a methodology that integrates security practices and security thinking at every phase of the software development process, ensuring that vulnerabilities are identified and mitigated before they become exploitable by users and threat actors. This thinking starts from the initial design phase of your application, all the way through to deployment. This proactive approach to cloud application development reduces the risk of data breaches. There are a few key tools and concepts in the SSDLC space that can help you secure your cloud application.Use Both SAST and DAST for Comprehensive Application Security Testing
Static application security testing (SAST) relies on tools like SonarQube or Snyk to statically look at the source code of your cloud application and identify insecure coding practices and/or code that could introduce vulnerabilities to your application. Once these vulnerabilities are identified, these tools offer fixes you can implement in your code to mitigate vulnerabilities. While SAST tools are great at picking up vulnerabilities in your code before it's deployed, certain types of vulnerabilities will only manifest after your code is running. That's why some SAST providers also provide dynamic application security testing (DAST) capabilities. DAST allows you to test your running application in a test environment, mimicking the conditions of a live deployment. DAST tools will test your running application with common attacks and malformed inputs and try to exploit authentication and API flaws. Where possible, use both SAST and DAST as complementary approaches to secure your cloud application. SAST ensures secure coding practices during development, while DAST identifies runtime vulnerabilities that could otherwise be missed. Together, these methods provide a comprehensive security testing strategy that reduces the risk of vulnerabilities making their way into production.Use Penetration Testing to Identify Security Gaps
Penetration testing, also called "pen testing," is a simulated cyberattack designed to evaluate the security of a cloud application and/or its underlying infrastructure. This can help to uncover common cloud application vulnerabilities, like SQL injection (SQLi) and cross-site scripting (XSS). Pen testing differs from DAST because it's an entirely manual process. It uses human ingenuity and tenacity to probe for complex vulnerabilities that might escape the eyes of an automated scan. There are two primary approaches to penetration testing:- You can employ your own internal pen testing team to probe and attack your own cloud application in a nondestructive, nonmalicious manner. The team's focus is to find vulnerabilities, not to exploit them. Vulnerabilities can then be reported to the development team for mitigation.
- You can also hire an external penetration team. These teams are usually provided by firms that specialize in identifying vulnerabilities by simulating real-world attacks against your application, just like any other threat actor would do. Their job is the same as an internal team: find and report vulnerabilities.
Use Containers and Isolate Services
A lot of cloud applications use container systems like Docker or Kubernetes to facilitate fast development and deployment. Beyond speed, there are also security benefits to using containers:- Service isolation: Containers enhance security by isolating your cloud application's processes and ensuring they run in a dedicated, self-contained environment. This separation minimizes the risk of a compromised process or application affecting others, reinforcing the security boundaries within your application.
- Immutable by design: Docker images are immutable by design, meaning they cannot be modified once created. Containers, which are instances of these images, can be replaced with updated versions rather than being modified directly. This approach minimizes the risk of introducing vulnerabilities by maintaining consistency and ensuring that changes are deliberate and traceable.
- Fine-grained access controls: Container systems like Kubernetes offer fine-grained access controls that enable role-based permissions between services.
Leverage Network-Level Isolation
Network-level isolation is an important aspect of securing cloud applications. It ensures that different components and environments are shielded from unauthorized access. Implement the following best practices to protect your internal services and APIs from unauthorized access:- Restrict network access: Protect internal services and APIs by limiting network access to trusted sources, such as specific internal services or approved IP ranges. Use virtual private clouds (VPCs) and configure firewall rules to enforce these restrictions.
- Avoid public exposure: Ensure that internal APIs and services are not accessible via the public internet unless absolutely necessary. If exposure is required, implement strict authentication and authorization protocols.
- Use API gateways: Deploy API gateways to control access, manage traffic, and keep internal endpoints hidden from external actors.
- Audit and monitor permissions: Regularly audit and monitor access permissions to minimize the risk of unauthorized exposure.
- Test configurations regularly: Regularly test API configurations for vulnerabilities to prevent common attack vectors.
Identity and Access Management (IAM)
IAM is a set of principles and best practices that ensures that only the right users, services, and software can access the right resources at the right time. This follows the principle of least privilege (PoLP), which helps reduce the risk of unauthorized access, data breaches, and exploitation of overprivileged accounts. PoLP is especially important in the context of cloud application security, where a typical cloud application might touch many data points, including accessing and storing confidential user information or interchanging data with authorized third parties. IAM is important for the users of your application as well as the business itself. It safeguards users' data not only from other users but also from threat actors inside and outside the organization. Just because an administrator maintains your application doesn't mean that they need access to payment card details that your application is storing. In a cloud environment, where your application might be subject to dynamic scaling, IAM ensures that cloud resources are used only by authorized entities and within approved limits. This prevents unauthorized access, misuse, or unintended consumption of resources, such as scaling up without oversight, which can lead to unnecessary costs or even security vulnerabilities. A strong IAM framework should include (but not be limited to) the following principles.Role-Based Access Control
Role-based access control (RBAC) is a fundamental principle of IAM best practices that ensures individuals and systems only have access to the necessary data required for their specific roles. For instance, a DevOps engineer responsible for the infrastructure aspect of a cloud application should never need to see customer data, while a customer support agent might need read-only access to specific portions of a customer's profile. Many cloud providers have tools that can help to set up and maintain RBAC:- Consider using AWS IAM to create detailed permission policies, including role-based access to AWS-specific resources.
- Microsoft Entra ID is Microsoft's take on a cloud IAM solution. It helps you set up RBAC to secure access to any application or cloud resource hosted on its Azure platform.
Multifactor Authentication
Multifactor authentication (MFA) adds a layer of security that goes beyond simple passwords. MFA forces privileged users to use another factor of authentication, like a hardware token or an authenticator app, after they've supplied their password. This significantly reduces the risk of unauthorized access to sensitive data. Make sure you configure sensitive data access, like viewing customer information or administrative dashboards, to require MFA. Also, consider requiring MFA for high-risk actions, like changing a customer's registered email address. This will strengthen your security posture by only allowing authorized users to make these high-risk changes.Data Protection and Encryption
Data encryption is considered a fundamental responsibility for any organization if they want to maintain their users' trust. Whether it's customer records, credit card data, or vendor information, encryption is an important layer of defense that can help to mitigate the damage of a data breach. Encrypting data at rest and in transit is essential for protecting sensitive information from unauthorized access at every stage of the data lifecycle.Encrypt Data at Rest
Data "at rest" refers to any stored data, like customer information in a database or backups of your production databases. The purpose of encryption at rest has many benefits. For instance, say an attacker gains access to your database or your backups. Without the proper decryption keys, they only have the encrypted data, which is useless and could take them millions of years to brute-force, depending on the encryption algorithm used. Additionally, even if you experience physical theft of your data storage, the same encryption is applied to the hard disk or other storage medium that was stolen. Even with physical access to your data, an attacker won't be able to glean anything useful from it. Common encryption algorithms, like AES-256, should be used to encrypt data on physical or virtual disks. While many cloud service providers (CSPs) now provide server-side encryption as a default setting, you should take particular care to identify any data stored in a system that does not provide this encryption by default. Data stored in specialized third-party databases or analytics stores would need to be encrypted as well.Encrypt Data in Transit
Not all data is stored; a lot of data is transmitted, either between your application and your users or between your application and a data storage medium, like a database. Data can also be interchanged between different APIs, including APIs that you might need access to but don't own or control. All data in transit is vulnerable to manipulator-in-the-middle (MITM) attacks, which can occur when your data traverses a network or a piece of equipment that you're not in control of, like a proxy server. If the proxy server has been set up to capture data that flows through it, any unencrypted data should be considered compromised. Transport Layer Security (TLS) is the standard protocol for encrypting data in transit. TLS works by establishing an encrypted connection between a client (like a browser) and a server, like the one hosting your web application. The two endpoints verify one another's identity using a system of digital, cryptographic certificates. The following are some best practices for when and how to implement TLS:- Always use TLS if you have any systems that transfer sensitive data between each other, even if they only communicate internally. This should mitigate the risk of MITM attacks by a malicious insider threat.
- Any public-facing endpoint, like your website or your APIs, should have TLS encryption enabled.
- TLS certificates can cost money, especially if you let your certificates be managed as a service. Consider your cost options vs. time saved by manually implementing and managing your certificates.
- Automate your certificate management as much as possible. Whether you use a paid service or implement an open source tool like CFSSL, automating your certificate management will go a long way toward reducing the possible frustration of working with certificates.
Implement a Key Management System
A key management system (KMS) is an important tool in your cloud application tool belt that helps you securely access sensitive data stored in other systems. Instead of passwords or access tokens being hard-coded in your application or your application database, keys can be retrieved on a just-in-time (JIT) basis. A KMS can also ensure the integrity of your sensitive information when you use best practices like the following:- Rotate keys: Regularly rotate your encryption keys to reduce the risk of long-term exposure if one of your keys is compromised. Should an old key leak somehow, periodic key rotation will make sure the key is not valid for very long.
- Use secure protocols: When you do share keys with a client system that requested them, make sure it's done over a secure protocol like TLS.
- Use PoLP: Use PoLP to ensure only relevant systems can request keys for the specific information they need access to.
- Azure: Microsoft has multiple key management solutions to choose from and has a dedicated blog post to help you choose the one that would be best for you.
- AWS: Amazon has its own key management service.
- GCP: Google's offering is called Cloud Key Management.