APIs are the backbone of the digital world, enabling seamless communication between applications and unlocking endless possibilities for innovation. But with this convenience comes a significant responsibility to keep our data secure. That's why API secure design principles are more critical than ever before and why we need to incorporate them into every stage of an API lifecycle.
From design to deployment and beyond, every step in the process presents new opportunities for attackers to exploit vulnerabilities and compromise our data. By integrating security into every stage of the API lifecycle, we can significantly reduce the attack surface and keep our APIs and their related data safe from harm.
But what exactly are we protecting against? The OWASP top 10 security risks for 2023 outline the most significant threats facing APIs today, including broken authorization, authentication, and function-level authorization, among others. Understanding these risks is a crucial first step in the design phase, not an afterthought once your APIs are already in production.
By building security into every aspect of the API lifecycle, we can proactively address these risks, reduce the likelihood of a breach, and avoid the costly and time-consuming task of backfilling or redoing work. So, let's start with security, let's prioritize it in every stage of the API lifecycle, and let's protect our data from harm.
API Secure Design Step 1:
When it comes to securing your APIs, simplicity is key. As the superb Gall's Law states, all complex systems that work evolved from simpler systems that worked. So, the first design principle is to keep it simple because simple means secure. Don't make securing a complex system or a collection of APIs harder than it has to be. Keeping things simple means it's easy to understand and fix when things go wrong.
When implementing security functionality like authentication and authorization, use the same concepts and ideas to keep things simple. Don't try to reinvent the wheel. Leverage industry standards that have been developed and vetted by multiple experts. There's no point in trying to build something better than an established industry standard.
It's also essential to start from a secure state by setting secure defaults. Make things secure by default, and don't let anyone turn them off. Secure, by default, should always be the norm. And if there are any changes to those secure defaults, raise a warning. Starting from a secure state is a critical part of the secure design process.
So, let's keep it simple, leverage industry standards, and start from a secure state. By following these principles, we can ensure that our APIs are secure and that our data is protected from harm.
API Secure Design Step 2:
The subsequent design principle is to do API versioning upfront. Versioning your API is a critical design principle that ensures a secure API. By utilizing versioning, we can continue to grow and improve our API over time while still maintaining backward compatibility. This approach allows for faster iteration and more frequent releases, enabling us to move quickly and stay ahead of the curve.
One of the most significant advantages of API versioning is the ability to make a clean swap of more robust security methods. By creating a new version of the API, we can add new and more robust security methods as a default while still maintaining the older version for backward compatibility. This approach ensures that we can keep up with emerging threats and stay ahead of potential security risks.
Another benefit of versioning is the ease of deprecating older, less secure API methods. We shouldn't think of versioning as keeping version one forever after we've created version two. Instead, version one should have an expiration date, and when version two is released, version one should expire in one year. By giving our customers plenty of warning, we can encourage them to migrate to the newer, more secure version of the API.
In summary, API versioning is an essential principle for designing a secure API. It allows for faster iteration, more robust security methods, and easy deprecation of older, less secure API methods. By following this principle, we can ensure that our APIs are always up-to-date and protected from potential security risks.
API Secure Design Step 3:
API secure design principle number three is all about enforcing the concept of "least privilege." It means that users should only have access to the most basic level of privilege necessary to perform their authorized tasks. In other words, if a user only needs to read data, then they shouldn't be given write access.
One effective way to enforce least privilege is to use role-based access control. This allows you to assign specific roles to each user or group, with each role having a predefined set of permissions. This ensures that users only have access to the functions and data that they need, without giving them unnecessary access.
Another best practice is to separate read and write API keys. Many APIs use a single API key with both read and write access, which can be risky. By separating these keys, you can ensure that each key only has the necessary privileges, reducing the potential for unauthorized access or misuse.
Remember, the key to enforcing least privilege is to focus on providing users with the minimal amount of access necessary to complete their tasks. By doing this, you can help ensure that your APIs are secure and that your users' data is protected.
API Secure Design Step 4:
In today's world, data is king, but that doesn't mean you should collect every piece of information that comes your way. Secure design principle number four is all about minimising the data you collect through your API. Why accept and store data you don't actually need? Not only does it create unnecessary clutter, but it also adds additional risk to your system.
To ensure you're only collecting what's necessary, document why you're collecting each piece of user data. This way, you'll be able to defend why you chose to store it if anyone ever questions your reasoning.
But that's not all. You must also document user consent when they give you data via the API. Users have the right to know what you're going to do with their data, so make sure you're transparent about it. Keep a record of their consent to assist you in case of any disputes about the data you've received.
By minimising the data you collect and being transparent with users about why you're collecting it, you'll not only reduce the risk of a security breach but also build trust with your users.
API Secure Design Step 5:
When designing a secure API, the fifth principle to keep in mind is to limit data exposure. This means we want to store only the minimum amount of data necessary behind our API. It also means we want to minimize the chances of accidentally exposing sensitive information to users.
Have you ever sent a piece of information to the front end of a user interface only to realize you attached something sensitive that got included in the JSON? We never show it in the UI, but the user could still see information about themselves or somebody else in that JSON. That's why it's essential to be vigilant and hunt for inadvertent disclosures of Personally Identifiable Information (PII) from multiple database correlations.
When thinking about how your API connects to the backend, be mindful of how someone could put together multiple pieces of information across different databases and API endpoints to pinpoint a user's identity or other sensitive information. By limiting data exposure, we can help prevent accidental or intentional leaks of sensitive information and protect our users' privacy.
API Secure Design Step 6:
Secure design principle number six is all about logging requests and responses in our API. By doing so, we can easily audit, debug, and search for any issues or potential attacks.
To make this process more efficient, we should add a unique request ID to each API request. This request ID helps us quickly identify and correlate multiple logs that may be attached to the same request. But we can't just build a request ID in any old way - we need to use a cryptographic hash to ensure that it's not predictable or easily manipulated by attackers.
Logging is crucial for security purposes. In the event of an attack, we need to be able to trace the source and determine how it happened. But logs can also be beneficial for debugging purposes. Instead of spending hours trying to track down an error, we can simply refer to the logs to pinpoint exactly what went wrong, where it happened, and when it occurred.
So, remember to log requests and responses in your API, and make sure to use a unique and secure request ID to simplify the process.
Part two, which goes into more detail and covers the implementation details required to shield your API and safeguard your data by embracing security best practices, is available here.