[BreachExchange] Why You Need to Think About API Security

[Destry Winant]

https://www.darkreading.com/application-security/why-you-need-to-think-about-api-security/a/d-id/1335861

Businesses of all sorts are increasingly relying on APIs to interact
with customers in smartphone apps, but they have their own unique set
of vulnerabilities.

As cyberattackers continue to take advantage of vulnerable people,
processes, and technology, they are also expanding their operations
beyond the usual targets. Nothing appears to be outside of their
jurisdiction, and no one is 100% safe from their malicious campaigns.
Although organizations are making progress in protecting themselves,
as soon as one attack vector is thwarted, another quickly becomes
exposed.

Today's adversaries are focusing on APIs in particular, which are
quickly becoming the new attack frontier. Recent reports suggest that
by 2022, API abuses will be the vector most responsible for data
breaches within enterprise web applications. This is primarily due to
the extensive growth of API implementations worldwide, providing a new
target that hasn't been widely exploited yet. With this, protecting
APIs is becoming more important.

Although the concepts of API security are somewhat new, the attacks
that can be performed through them are not. Most organizations have
been experiencing similar threats targeting their networks and
Internet-facing applications for years. Now, they must focus their
efforts on mobile apps, APIs, and back-end servers being targeted by
similar methods as seen in the past. Before discussing the risks
associated with today's APIs, we must first understand exactly what
makes them unique and vulnerable.

API-Based Apps vs. Traditional Apps
API-based apps are significantly different from traditional
applications. In the past, users/visitors would access a web server
via a browser, for example, and most of the "data processing" was
performed on the server itself. As client devices became more varied
and increasingly powerful — with faster CPUs, extensive memory, more
bandwidth, etc. — much of the logic moved away from being performed on
back-end servers to the front end (that is, on the client device
itself) as highlighted in the graphic below.

In the modern application at the bottom of this graphic, the
downstream server acts more like a proxy for the data consumed by the
API-based app. The rendering component in this instance is the client
that consumes the raw data, not the server itself.

Many will remember the early days of using smartphones and traditional
websites when trying to reserve a flight, for example. People would
open a browser on their phone and attempt to use an airline website
that was designed for a large computer monitor, not a small smartphone
screen. This didn't work too well, and companies began to update their
websites by making them more smartphone-friendly. Although this
improved the customer experience, navigating a website and completing
an airline reservation was still quite cumbersome.

As a result, airlines, hotels, car rental companies, etc., began to
develop their own mobile apps. Instead of trying to reserve a flight
using a mobile-friendly version of the airline's website via a browser
on their phone, people now download and install the airline's mobile
app and use it exclusively when reserving flights directly from their
smartphones. So, how is this different?

When making a flight reservation using an airline mobile app, the app
uses API calls that are interacting with back-end servers primarily to
retrieve data about flight schedules, availability, pricing, seats,
etc. The app is also interacting with the user, allowing the customer
to specify travel dates, departure and arrival cities, seat selection,
and purchase options. In this case, the smartphone is performing
almost all of the processing load of the flight reservation within the
mobile app itself, without the use of a browser. Although this has
tremendously improved the flight reservation experience overall when
using a smartphone, it raises the question: Are APIs just as
vulnerable to cyberattacks as browser-based applications?

The Risks Associated with APIs
Unfortunately, APIs are also exposed to attacks and, at a very high
level, API security issues exist, similar to their browser-based
counterparts. However, since APIs expose the underlying implementation
of a mobile app, and the user's state is usually maintained and
monitored by the client app, plus more parameters are sent in each
HTTP request (object IDs, filters, etc.), some of the security issues
surrounding APIs are unique. For the most part, these issues lead to
vulnerabilities that can be categorized into three areas of concern:

Exposing sensitive data
Intercepted communications
Launching denial-of-service (DoS) attacks against back-end servers

A Good Project with a Nobel Cause
As a result of a broadening threat landscape and the ever-increasing
usage of APIs, I, along with Inon Shkedy, head of security research at
Traceable.ai, have been spearheading the OWASP API Security Top 10
Project. The project is designed to help organizations, developers,
and application security teams become more aware of the risks of APIs.

Here's what makes the project important: According to the project's
site, "a foundational element of innovation in today’s app-driven
world is the API. From banks, retail, and transportation to IoT,
autonomous vehicles, and smart cities, APIs are a critical part of
modern mobile, SaaS, and web applications, and APIs can be found in
customer facing, partner facing, and internal applications. By nature,
APIs expose application logic and sensitive data such as Personally
Identifiable Information (PII) and because of this, have increasingly
become a target for attackers. Without secure APIs, rapid innovation
would be impossible."

The OWASP API Security Project aims to develop, release, and track an
ongoing top 10 list of the risks that organizations face concerning
their use of APIs, similar to the OWASP Top 10 Most Critical Web
Application Security Risks. From broken object-level authorization to
insufficient logging and monitoring, this list rounds up the most
critical API risks facing businesses while also providing example
attack scenarios and recommendations for mitigating these threats. IT
teams, security professionals, and developers alike would be
well-advised to carefully read through this list to better understand
the benefits of APIs, as well as the potential risks presented through
their implementation as adversaries set their sights on this emerging
target.