What is API Authentication?

In the classic French thriller “Diva,” a crook mocks a police officer’s badge by saying, “ID? That stands for ‘idiot’s delight.’” The film came out in 1981, the same year as the IBM PC. The sentiment on display was ahead of its time. The bad guy was anticipating the cybersecurity problem of authentication, which is now reaching crisis proportions. System access should only be granted to users who can prove they are who they say they are. This is a foundation of cybersecurity. Otherwise, it’s “idiot’s delight,” and unauthenticated or falsely authenticated users will enter places where they don’t belong.

The issue is all the more pressing when it comes to APIs, which often sit in front of vast stores of sensitive information. API authentication is the solution to user authentication. It enables API owners to guard against improper API access from users who cannot verify their identities.

A proven API authentication method

API authentication is a combination of technology and processes that verifies the identities of users requesting API access. It employs software protocols to ensure that users are who they claim to be when making API calls. API authentication solutions are designed to block access if irregularities are detected during the authentication process. Essentially, it acts as an online ID verification mechanism, safeguarding APIs from unauthorized access, particularly from malicious actors. It’s important to note that in many instances, the API user may be a machine rather than a person.

The importance of API Authentication

API authentication plays a crucial role in ensuring the security of APIs and, by extension, the overall cybersecurity defense of an enterprise. APIs serve as access points to valuable and sensitive data, as well as software functionality. Without proper authentication mechanisms in place, unauthorized and untrusted users may gain access to the data or functionality exposed by the API. This can lead to various risks, including data breaches, corruption or deletion of data, and denial-of-service (DoS) attacks.

Done correctly, API authentication reduces the likelihood of attacks and mitigates their impact should they occur. It also leads to greater user trust. In many cases, especially those involving financial information or personal data, users appreciate API authentication even if it adds extra login steps. It makes them feel more confident that their data is protected.

What are API keys?

An API key is a unique numeric identification code that authenticates an API user. It’s the basic element of API authentication. In particular, a known API user will have an established API key. When requesting access to the API, the user will submit the key to the API security solution. The API security solution will, in turn, either grant or deny access to the API based on the validation of the API key. This process usually occurs without a human user having to take any specific action. Rather, this handshake and key inspection process occur on a machine-to-machine basis, out of view. A first-time API user will have to receive an API key, which usually occurs after the individual’s (or machine’s) identity has been validated by other means.

How does API Authentication work?

API authentication involves presenting a credential and/or supporting data, which is then accepted or rejected. Credentials can take the form of an API key, username/password pair, or digital token. Supporting data may include information related to the user’s device or location. For instance, if a user is based in Boston but the device using their credentials is located in London, the user’s identity may be compromised. Either the user traveled to London, or someone is impersonating them. A well-configured API authentication solution should detect such anomalies and respond by blocking the user until further verification steps, such as one-time passwords, can be completed.

API authentication vs API authorization

Authentication alone is not enough to ensure API security. After all, authentication only establishes a user’s identity. It does not determine what kind of API access he or she is entitled to have. That is a matter of authorization. It’s like the difference between a key to a building and a key to a room inside that building. The first key gets you in. That’s authentication. The second key lets you into a specific room. That’s authorization. With APIs, authorization is about what level of access the user is entitled to receive.

Types of API authentication methods

There are three popular methods for API authentication:

• HTTP Basic Authentication — The simplest form of API authentication only requires users to create a username and password with Base64 encoding. This method uses the HTTP header, making it simple and straightforward. No additional solutions are necessary.
• API Key Authentication — API key authentication was created to address the vulnerabilities of shared credentials, which made HTTP Basic Authentication an inadequate method. In API key authentication, the API security solution authenticates the API key, confirming the user’s identity, and granting access to the API. The API key is sometimes called a “bearer token.” The idea is that if you possess the token (are the bearer of the token), you are authorized to communicate with the API.
• OAuth Authentication — Able to handle authorization as well as authentication. The API requests authentication, which takes the form of an OAuth token that is forwarded to an authentication server, which accepts or rejects it. The token has limited allowed uses and often an expiration time.

Pros and cons of popular methods

There are advantages and disadvantages to the common methods of API authentication. For instance, HTTP Basic Authentication is straightforward to use, which is a significant benefit. However, the sharing of username and password pairs introduces security risks, especially in the context of man-in-the-middle attacks. Therefore, it is essential to secure the process with a secure socket layer (SSL).

API keys are an improvement over HTTP Basic Authentication because they use long, usually unguessable keys. However, API keys do not provide authorization, meaning that an attacker with an API key can often gain unrestricted access to all data and processes associated with the API.

OAuth is considered a robust protocol for API authentication, especially with mobile applications, due to its wide support and popularity. However, it does have some drawbacks. OAuth is more complex to set up and manage compared to other methods. It necessitates a dedicated solution, which can incur costs for acquisition and ongoing support.

API authentication is a crucial security measure for protecting APIs from unauthorized access. It encompasses various processes and technologies. Three main methods of API authentication are commonly used: Basic authentication, API key authentication, and OAuth. While OAuth is considered the most secure, it can also be complex to manage. For effective API authentication, it should be complemented with API authorization, making sure that only authorized users have access to specific data and processes based on their permissions.

How Noname can help

Noname’s API security platform can help you protect your APIs with authentication issues.  We test APIs early and often throughout the SDLC, so authentication issues are discovered and remediated sooner rather than later. You can quickly re-test for vulnerabilities previously discovered to confirm the fixes have taken effect. Early testing in pre-production environments can reduce or eliminate threats like broken user authentication issues before they can be exploited.

For APIs in production, we provide runtime protection to monitor and analyze all API traffic. Our platform has an established baseline for many types of APIs, like REST, GraphQL and SOAP. By having a baseline for normal API communication methods, our anomaly detection, powered by AI and machine-learning, can pinpoint when an attacker is trying credential stuffing or password spraying against an API. We can also alert you if there are surges of authentication failures – a typical outcome of probes for weak user authentication.

If an attack has been identified, Noname offers a flexible range of ancient response options. This includes integrations with ticketing systems like JIRA or ServiceNow, which allow Noname alerts to be triaged by your security team. You can also elect a fully automated approach to incident response, which immediately blocks the IP address for predetermined time period. Our platform can de-authenticate a client’s access token at the API gateway. APIs without proper authentication are automatically cited as vulnerable.

Lastly, our platform dynamically creates an inventory of all of your APIs. You can catalog your APIs based on hostname, path/URI and HTTP method. Beyond knowing how many APIs you have, you also get insight into the types of sensitive data that traverse your APIs. You can even create custom data types to accommodate business-specific data, and restrict sensitive data in API communications.

For example, a policy to disallow credit card numbers from ever leaving an API could be created. Any policies on data are enforced by the platform’s runtime protection including policies around authentication token use.