Serverless has transformed the approach to development by eliminating the need to manage the underlying infrastructure. As a result, Serverless was the highest growth public cloud service, according to the CBInsights research.
However, currently, the serverless ecosystem has matured. According to MarkNTel, the global serverless security market is expected to grow at a CAGR of around 25.85% from 2022 to 2027.
This evolution highlights that organizations will choose serverless options in the future, and many businesses will leverage this technology.
It’s also no surprise that serverless application architecture has improved its security. But, there are still threats that persist since serverless apps embrace hundreds of functions. It means that maintaining security needs to adopt and follow best practices. Before moving ahead, let’s quickly know about serverless security and challenges.
As you may already know, serverless is a cloud-native development technique wherein developers don’t need to manage servers. But, they need to deploy code as functions and servers are assigned based on demand. In simple words, it also enables developers to create and execute applications without managing servers.
Talking about how security works in serverless, the serverless providers, e.g., AWS Lambda or Google Cloud Functions, are responsible for securing cloud components (network, sensors, data center & operating systems). But, it merely reduced the burden of security. However, app developers are responsible for application logic, code, data, and application-layer configurations, making it a shared responsibility.
What are Serverless Security Challenges?
When the code is written in a way that does not follow security best practices or the functions use a lot of permissions, then it can be vulnerable to different security attacks. So, it is important to approach the functions differently. This is because serverless functions operate differently compared to traditional application platforms. They can live for a few minutes, and the maximum duration to run a function is only 15 minutes. Serverless functions can be triggered by an event or a simple SMS. Therefore, it can change everything.
In a traditional monolithic app, the attack surface is generally predictable; however, serverless functions use a variety of event sources such as HTTP APIs, cloud storage, IoT device connections, and queues. In short, serverless functions. The attack surfaces may be increased since some of these parts contain untrusted message formats.
Furthermore, serverless apps are stateless, and if the function’s authentication is mishandled in an app with hundreds of serverless functions, then it impacts the rest of the application. Attackers can focus on one function in order to get access to the system via different methods, for example, dictionary attacks and automated brute-force attacks.
6 Best Practices for Serverless Security
Check out some of the best practices that can secure your serverless functions:
1. Use API Gateways as security buffers
Separating data from functions using API HTTPs endpoint gateways is one of the best ways to prevent event-data injection. When different sources fetch data, the API gateway acts as a security buffer, separating app users on the client-side and serverless functions on the backend. Hence, it helps reduce the attack surface by offering several security checks using reverse proxy.
In simple words, use HTTPs endpoints that can help you leverage in-built security protocols (e.g., data encryption), which can help to protect the stored sensitive data and environment variables.
2. Insecure authentication
This serverless security best practice can enforce customized password complexity requirements such as length and character type in the password. Therefore, it becomes harder to crack for hackers. When handling the risks arising from broken authentication, you need an implementation of multiple specialized access control and authentication services. Use CSP’s access control solutions (OAuth, OIDC (OpenID Connect), SAML (Security Assertion Markup Language) & MFA (Multi-factor Authentication) if authentication is hard to penetrate.
This serverless security best practice can enforce customized password complexity requirements such as length and character type in the password. This way, hackers find it challenging and can’t crack the passwords.
3. Cut down privileges
One of the best practices is to cut down privileges in independent functions. You can do this by separating them from one another and limiting their interactions. Provisioning IAM roles can do it. On the other hand, the second method is to ensure that the code runs with the least number of permissions for performing a successful event.
4. Controlling sensitive credentials
The other serverless security best practice is to handle sensitive credentials, which generally plays an important role in security. Sensitive credentials mean storing databases in a safe place and keeping their accessibility extremely limited. Furthermore, keep an eye on API keys also. For example, Azure functions use environment variables with “Key Vault.” Below, you can see an example of Python code in which an API key is stored on System Manager Parameter Stores.
# Using System Parameter Parameter Stores to store third party API Key
ssm = boto3.client(‘ssm’)
parameter = ssm.get_parameter(Name=’MY_ACCESS_TOKEN’, WithDecryption=True)
In the above example, the function can call an AWS API call to access in order to access the access token, which is stored in the SSM Parameter stores without hardcode anything.
What’s more? Follow these best practices to make the most of it:
- It is advisable not to use the same configuration file in multiple functions. The best method to prevent this issue is to rotate the keys regularly, even if it is hacked. It simply ensures that access to hackers is cut off.
- All the individuals (component, developer, project) must have separate keys.
- Moreover, encrypt sensitive data and environment variables by using encryption helpers.
5. Secure SDLC
Software Development Lifecycle (SDLC) provides a framework to develop software applications and manage and streamline the development process. However, an insecure application is bound to become a risk for businesses. Such insecure and vulnerable apps result in personal sensitive information and data loss and damage business reputation.
These vulnerabilities generally happen during the testing phase in the development process. To prevent the loss of money and risks to your business, integrate security during the process. It helps you in the following ways:
- It guarantees authorization and ensures that an application works properly.
- It constantly checks and reviews the conditions for weaknesses. Hence, it ensures that the app is aligned with security best practices.
6. Geographic considerations
Developers should understand that geographic conditions also affect serverless security while deploying application modules. For example, if the code is deployed from different locations, it can create code-related risks due to completely different time zones in deployment settings.
One of the best serverless security practices you should adopt is to use a single geographic location or an ideal time zone for deployment. Furthermore, you can use a safeguard to avoid unexpected development challenges and manage work dependencies while working with a serverless framework.
Conclusion: Staying Ahead of Serverless Security Risks
Like any cybersecurity practice, securing serverless applications is essential throughout the application development lifecycle. A proper development process is insufficient, but following best practices can surely help to improve security posture. Adopting serverless security tools (Protego & PureSec) can provide security assurance, attack detection, prevention, and deception.
Serverless architecture has tremendous benefits, and all you need is a dedicated solution to help developers do the right thing while adopting serverless security best practices.
If you want to add your thoughts on serverless security best practices, comment below.
Also Read: Serverless Is A Security Nightmare