Best Practices For Securing Serverless Functions: A Practical Guide
Technology delivery is constantly changing, but the fundamental need to protect your business data remains exactly the same. Since 1980, CTS Companies has helped businesses in Michigan figure out which technology they need to solve problems in a simple and reliable way. Today, many organizations are shifting toward serverless architecture to reduce infrastructure management and improve scalability. However, moving away from traditional servers does not mean moving away from security responsibilities.
Without a physical server or operating system to manage, IT teams often assume the cloud provider handles all the security. While providers secure the underlying infrastructure, protecting the actual code, data, and access remains your responsibility. Implementing the best practices for securing serverless functions ensures your applications run efficiently without exposing your network to unnecessary risks. In this guide, we will walk you through clear, straightforward strategies to protect your serverless environments.
Understanding the Serverless Security Landscape
In a traditional IT environment, security often focuses heavily on the network perimeter. You build firewalls, monitor server traffic, and manage operating system updates. In a serverless model, the perimeter changes. The application is broken down into small, individual functions that are triggered by specific events. This fragmentation creates a larger attack surface. Every function, API gateway, and database connection represents a potential entry point for malicious activity.
Security runs through nearly every decision an IT manager makes. At CTS, we look at security through a comprehensive lens, including physical security, password policies, antimalware, remote access, and web filtering. When applying these concepts to serverless computing, the focus shifts to strict access controls, secure coding practices, and continuous monitoring. A solid cybersecurity strategy must account for these modern application structures to prevent data breaches and unauthorized access.
Core Best Practices For Securing Serverless Functions
Securing a serverless environment requires a proactive approach. By setting up strict policies and procedures early in your development cycle, you can prevent most common vulnerabilities. Here are the primary areas your IT team needs to focus on.
Enforce Strict Identity and Access Management
The most critical step in serverless security is applying the principle of least privilege. In many standard setups, developers might assign broad permissions to a function just to get it working quickly. This is a major security flaw. If a function is compromised, the attacker gains access to everything that function can touch.
Each serverless function should have its own unique identity and access role. If a function only needs to read data from a specific storage bucket, do not give it permission to write or delete data. Do not give it access to other databases it does not need. By restricting permissions to the absolute minimum required for the function to execute its task, you limit the potential damage of a breach. This approach aligns closely with strong internal password policies and access procedures.
Secure Application Code and Dependencies
Serverless functions rely heavily on third-party libraries and dependencies. While these pre-written code packages save time, they can also introduce vulnerabilities. If a library you use contains a known security flaw, your serverless function inherits that flaw.
To mitigate this risk, you must continuously scan your code and its dependencies for vulnerabilities. Automate these scans within your deployment process so that vulnerable code is flagged before it goes live. Additionally, write clean, secure code that sanitizes user input to prevent common attacks like injection flaws. Treat your serverless code with the same rigor you would treat any traditional application.
Protect Sensitive Data and Secrets
Never hardcode sensitive information like API keys, passwords, or database credentials directly into your serverless function code. If your code is exposed or accidentally shared, those credentials become public. Instead, utilize dedicated secrets management tools provided by your cloud vendor.
These tools store sensitive data securely and allow your functions to request the information dynamically during execution. Furthermore, ensure that all data is encrypted both at rest and in transit. Protecting data as it moves between functions and databases is a fundamental requirement for a secure IT infrastructure.
Implement Robust API Security
Serverless functions are typically accessed via Application Programming Interfaces (APIs). If your APIs are left unprotected, they can be overwhelmed by malicious traffic or accessed by unauthorized users. To secure these access points, implement API gateways that require proper authentication and authorization for every request.
Additionally, configure rate limiting and timeouts. Rate limiting prevents a single user or bot from spamming your API, which can lead to denial-of-service attacks and unexpected billing spikes. Setting strict timeout limits ensures that if a function gets hung up or compromised, it shuts down automatically rather than running indefinitely.
Integrating Backup and Recovery Plans
Even with the best security practices in place, incidents can still happen. A compromised function could accidentally corrupt database entries, or a malicious attack could delete critical files. Because serverless applications constantly interact with stored data, ensuring that data is backed up is crucial.
Whether you decide to implement on-site, off-site, or a mixed storage solution, CTS has specialized in business continuity since the late 90s. Your serverless architecture must connect to a secure, isolated backup environment. If your primary data store is compromised, you need a tested, reliable way to restore operations quickly. Building a comprehensive data backup and recovery plan guarantees that a temporary security failure does not become a permanent business disaster.
Continuous Monitoring and Logging
Because serverless environments spin up and down rapidly, tracking what happened during a security incident can be difficult. Traditional server monitoring tools often fall short because there is no persistent server to monitor. Therefore, you must enable detailed logging for every function and API request.
Send all logs to a centralized, secure logging platform where your IT team can analyze them. Set up automated alerts for unusual behavior, such as a function taking longer than usual to execute, repeated failed access attempts, or a sudden spike in data transfers. Visibility is your best defense. If you cannot see what your serverless functions are doing, you cannot secure them.
Partnering with a Reliable Technology Expert
Managing the complexities of serverless architecture, strict access controls, continuous code scanning, and data recovery requires significant time and expertise. Many businesses do not have the internal bandwidth to handle this on top of their daily operations. While some companies force you into one type of partnership, we deliver across a spectrum from one-off projects to acting as your full IT department.
Working with an experienced managed service provider ensures your technology infrastructure is designed securely from the ground up. If your team needs ongoing assistance, we offer a mix of help desk solutions, including full on-site members, bulk rates, and reactive support. Choose the option that best suits your business needs.
Securing modern technology doesn’t have to be complicated. By following these best practices for securing serverless functions, implementing least privilege access, monitoring your systems, and ensuring reliable data backups, you can protect your business from evolving threats. If you need help evaluating your current infrastructure or implementing a more secure approach, reach out to our team. We are here to help you solve your business problems in a simple, reliable way.