API security – How to prevent attacks?

By Thomas Gonzalez|Posted 08 Jun, 2022

API security – How to prevent attacks?

An API or Application Programming Interface is a piece of software that enables different applications and services to communicate or exchange data. 

Modern applications work by exchanging data with multiple applications in order to boost their functionality. Without APIs, communication between different applications would not be possible. APIs are mainly used by web applications that use the microservices architecture.

The popularity of APIs in the last couple of years has caught the attention of cyber-attackers too. These attackers are now constantly coming up with ways of taking advantage of the vulnerabilities in APIs to destabilize or freeze the operations of apps that rely on them to operate. 

To avoid being the next victim, it is important to prioritize the security of your APIs at all stages; development, deployment, and maintenance.

Just like any other software, APIs need to be tested frequently to ensure any detected vulnerabilities are addressed before they are exploited by attackers.

In this article, we will discuss the common API attacks and how you can prevent hackers from compromising your APIs using any of these attacks. Let’s get started!

Common API attack types

Before we get into the various ways to prevent your APIs from being attacked, let’s first look at some of the common API attack types.

  1. API Injection Attacks

This has been one of the most popular API attacks in recent years. With this attack, the hacker injects malicious code into your software with the main aim of gaining access to its data. Once the attacker is successful, they can use this malicious code to take control of your application or extract sensitive data from it.

2. Parameter Tampering

With parameter tampering, the attacker manipulates the parameters between the client (browser) and the server (for a website or web app) with the aim of modifying the application data such as the credentials and permissions. In some situations, the data input by the user into a form field is manipulated without the user’s permission.

3. Man in the middle attacks (MITM)

Just like you might have guessed, this is the kind of attack where the attacker interferes with requests and messages between two parties communicating via the web to gain sensitive information. If a hacker gets in between the communication between a client and server, they will gain access to all information being exchanged between the client and the server. This information may include users’ login credentials such as their password, username or email.

4.DDoS attack

DDoS stands for Distributed Denial of Service, which is a type of cyber-attack on a web application or website that aims at disrupting the traffic of a particular network or a targeted server. Usually, these attacks are carried out by overwhelming your web app or website servers with artificially generated traffic hence making it hard for the actual visitors of the site to access it.

5. Authentication hijacking

This refers to the kind of attack where hackers compromise a session token by stealing or guessing a valid session token hence gaining access to a web server. With this attack, hackers will attempt to bypass the authentication methods used by your APIs by guessing the session code or stealing it from actual users.

6. Data exposure

This form of attack usually happens when applications do not correctly handle the exchange of sensitive data (such as payment information and login credentials). Hackers can do whatever they want when they land on this kind of information.

How to prevent API attacks

Now that we know the common ways hackers could attack your API, let us look at the API security best practices that you can use to protect your API from being compromised.

  1. Multifactor authentication

Two Factor Authentication (2FA) is the most common method used to enhance the security of web applications and APIs. With 2FA, a user is sent a code via SMS or emails whenever there is an attempted login from a distant location or another device. So, a user needs to have this code before they get access to your account.

So, even if an attacker gets access to the login details of a certain user, they won’t get access to the account unless they guess the 2FA code, which is very unlikely. It is also important to encourage users to change their passwords or even their email if they ever get notified about an attempted login to their account that was not made by them. All the best popular web applications we know, including Facebook, Gmail, and Amazon use 2FA to help enhance the security of their users.

2. Encrypt all your data

Another practical way you can prevent hackers from compromising your APIs is by encrypting all traffic that is coming to and from your servers. This is one of the most effective ways you will deal with man in the middle attacks. Even if the hacker gets access to the data while it is in transit, it will be meaningless to them since it is encrypted.

Use Secure Sockets Layer (SSL) or Transport Layer Security (TLS) to ensure all the data sent and received by your servers and the users’ browsers is encrypted. You should also consider implementing encryption at rest to ensure that hackers who get access to your API servers do not make use of the data on these servers.

3. Use a service mesh

A service mesh is a dedicated infrastructure layer that ensures secure communication between containerized application infrastructures. Using a service mesh applies different layers of management and control when routing requests from a given service to the next. With a service mesh, security is handled more efficiently, by combining security and operations capabilities into a transparent infrastructure layer in between the containerized applications and the network.

As more applications are now adopting the microservices architecture, using service meshes is becoming one of the most effective ways to ensure secure communication between the different services and APIs.

4. Use the Zero-trust Philosophy

This philosophy assumes that there can be attackers both outside and within the network, so all users or machines should be verified before getting access to the network. Traditionally, networks had some form of perimeter and all elements inside this perimeter were trusted and those outside were not. With the zero-trust philosophy, no elements are trusted, whether inside or outside the perimeter; they all have to be verified before being granted any level of access.

With this philosophy, the security focus is shifted from location to specific users, machines, and resources. Using zero-trust philosophy will ensure that APIs authenticate all users and applications (both inside and outside), give them the least possible privileges they need, and closely monitors for any abnormal behaviours.

5. Rate Limiting and Throttling

Rate limiting enforces a limit on the number of requests or the amount of data a certain client can consume. With rate-limiting, a single client cannot overwhelm the API with so many requests. Rate limits are usually calculated in requests per second. This strategy is specifically used to deal with DDoS attacks on APIs.

Rate limiting will also balance access and availability by managing and regulating user connections. Using this strategy will significantly limit the impact of any DDoS attacks on your API.

6. Take advantage of OAuth

OAuth, which stands for Open Authentication is a protocol that allows third-party services to exchange information without exposing the user credentials. Using OAuth, you will protect sensitive user information from being leaked to hackers.

7. Use push notifications

Another effective way of boosting your API’s security is by using push notifications that are sent by the receiving system to the user’s phone. Users can set up the push notification system when they are signing up on the application for the first time. So, whenever there is an attempted login using another device, the user receives a push notification.

This may not directly fight the attack, but it alters the user hence allowing them to fight back and save their account from being compromised by the attacker.

Final thoughts

We have looked at some of the API attacks that have been pretty common in the last couple of years. Knowing about these attacks alone is the starting point to help app and API developers to find ways of improving API security from the ground up. 

We have also discussed some API security best practices that you can implement to enhance the security of your APIs. Try to implement all of them if you can.

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