7 Efficient Practices For API Security

API is the key tool for building applications that have the ability to interact with other applications and services.  The openness and visibility of API is a boon and bane at the same time. By increasing the number of ways in which malicious entities cause chaos by gaining unauthorized access to the applications, API increases security risks by multiple folds. Failsafe application of security controls is necessary during the design phase of applications in order to overcome possible security challenges.

In this article, we discuss seven strategies that can be followed throughout the software development cycle to improve API security.

Ensure That The API Security Clues Are Hidden

Giving valuable clues to malicious users puts you at fault for attacks. The majority of organizations have some security controls that are viewed as a disadvantage in some cases. Attackers have all the time in the world to launch an attack at a time when you least expect it.

Consider a situation that serves as the perfect example of security clues increasing the chance of malicious attacks. Suppose you have a user authenticating by typing the username and password and they type the correct username but enter the wrong password. It is recommended that you do not expose that information through a response, that is often coupled with the reason.

Consider the response code, Status code:401, Reason: WRONG_PASSWORD

From such a response, an attacker will learn that that the username is right and they will shift their focus to finding the right password. Their work is half done already. A reasonable response that you can give in this situation is:

Reason: INVALID_USERNAME_PASSWORD_COMBINATION

Authenticate Prior To Authorizing

Sensitive and private information has to be authenticated in order to decide the user identity. Authentication can be performed in different ways and a multi-factor type of authentication is recommended for added security, whereby two or more pieces of evidence are used in determining the identity of the requester. APIs generally use an access token that is gained through an external process, for example when you sign up.

The authentication keys have to be kept secretively, and it is generally recommended that you maintain a secret management store in order to automate the overall process. However, authentication does not mean all the work is done. It has to be followed by an authorization step to decide what resources the identified user has to be granted access to. Different ways to check proper authorization include Content-Based Access Control (CBAC), Role-Based Access Control (RBAC), and Policy-Based Access Control (PBAC).

Enforce Encryption Throughout API Communication

Encrypting the communication flow using advanced cryptographic encryption methods is regarded as a fundamental security requirement. It ensures that the authentication credentials during transit including AP keys, tokens, and passwords are protected well. Consider adding extra layers like mutually authenticated certificates on top so that both parties involved in the communication can be certain that their API communication cannot be tampered.

Make Use Of Resource Quotas And Throttling

When you are protecting your APIs against DDoS attacks, it is essential to have rules that put restrictions on usage after certain criteria are met. This would include monthly quotas, requests per time unit, and bandwidth limits. 

To ensure availability and fair usage of business services, use more detailed rules for back-end intensive operations.

Realize The Importance Of Proper Validation

Securing the APIs typically means securing its request-response cycle. Input is taken in via the URL as parameters or the request body as content, which is then received by the API backend to process. It is at this stage when most attacks originate, as it is the easiest way for attackers if there are missing security controls.

For parameters, it is generally recommended not to trust any sort of input strings or objects blindly and validate them against a certain set of rules and regulations. Request payloads may include headers, attachments, or body text, and it is important to validate them against integrity and conformance.

Data leaks or obvious content should not be a part of the response entity.

REST API Design

REST API design is proven to be successful in reducing the complexity of applications and making them more understandable. While using the REST framework, you stick to certain rules and guidelines that contribute to improving the API security by design. For example, you can consider applying whitelisting to certain HTTP methods and reject anything that is not compliant with the contract guidelines. You can avoid responding through text and instead follow an HTTP return code table with the semantic response so that it does not expose sensitive information unintentionally.

Auditing And Logging

Auditing is a step that you should not skip by any means. Any entity or subject can be audited, and this feature has to be effectively used to detect and proactively deter attacks. Auditing is especially important in the case of the container ecosystem because only a few elements are used to run the app. The security threats that affect containers could further cause threats to API security, which is why we strongly recommend you to ensure that proper inspection tools are used.

Make Use Of Additional API Resources

An important step in risk mitigation is to understand how the best practices can be applied to APIs and protect the underlying platforms. A holistic approach in terms of security is important in designing APIs as they are part of a larger infrastructure.