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5 Reasons to Pentest your APIs

  • APIs are prolific today and much of your core operations leverage them.

  • Most APIs have many unknowns, making them an easy attack vector.

  • Pentesting your APIs is the most cost-effective way to understand real flaws in coding and business logic.


The explosive growth in recent years of APIs shows no sign of slowing down yet. By facilitating communication between different applications, APIs open up a wealth of possibilities to automate aspects of development, innovation, and improvement of the user experience.

Today’s API-enabled digital ecosystems offer many benefits, but the downside is that API security isn’t where it needs to be. Threat actors increasingly set their sights on APIs as targets for cyber attacks. Data breaches, DDoS attacks, and fraudulent transactions are some of the potential consequences of lax API security.

The prevalence of APIs and the perception of their weak security led to 95 percent of surveyed organizations experiencing an API security incident between 2021 and 2022. Businesses need an actionable API security strategy that strengthens their security posture—this article explains why API pen testing should be a crucial part of that strategy.

The Growing Use of APIs

API calls account for 83 percent of web traffic! Apart from the alluring business benefits, analyzing the growth of APIs from an operational perspective reveals some deeper factors influencing their continued proliferation:

  • Widespread cloud migration to SaaS applications creates a bigger need for integrations.

  • The increased need for agile software development means leveraging pre-built tools and services rather than coding from scratch. It’s much faster to link to an existing API to get what’s needed for an app or service.

  • There are more mobile apps than ever, and many of these apps have the majority of their functionality powered by APIs. Consider how a ride-sharing app might call social media APIs, Google Maps, and PayPal to provide three core components; user registration, real-time navigation, and payment.

  • There is an overall expectation for apps and services to connect to each other in today’s tech landscape. Every software vendor has an API! But, is it safe?

5 Reasons to Pentest APIs

An API pentest systematically assesses the security of your APIs by identifying security vulnerabilities and attempting to exploit them in much the same way as a genuine malicious outsider would. However, many API security incidents stem from business logic flaws that require the thoroughness and depth of a pen test to uncover. Here are five compelling reasons to pen test your APIs.

1. Ad Hoc Processes Increase Risk

The ad hoc nature of API coding leads to increased security risks. Developers get tasked with coding APIs at a point in time when the business deems it necessary to expose an application’s functionalities and build the bridge that facilitates connecting to other apps and services.

With ad hoc processes, it’s easy for developers to get sloppy with their coding and forget to pay attention to secure coding practices. After all, coding an API is fundamentally about interconnectivity, so it’s this task that takes precedence. Further increasing the risk is the somewhat hidden nature of APIs. Developers may not emphasize API security as much because they don’t think anybody sees the API.

Run through a list of recent high-profile API security incidents and you’ll find evidence of sloppy coding. In one case, a security researcher uncovered serious and basic flaws in an API belonging to credit reporting company Experian. The errors included using publicly available information to authenticate requests and not properly validating authentication. An API pentest uncovers these sloppy coding practices.

2. API-Specific Threats

With API development being less disciplined from a security perspective, there are many new and emerging threats to contend with. Threat actors see APIs as an enticing path to compromising an application, database, or internal infrastructure. Malicious outsiders may focus on reverse engineering client-side code, authentication hijacking, parameter tampering, man-in-the-middle attacks, API injections, and API key pools. Penetration testing can unearth any weaknesses that make these threats more likely to succeed in compromising an API.

3. New Ways to Exploit

APIs are susceptible to living off-the-land cyber attacks in which threat actors take advantage of the way APIs work without flagging any indicators of suspicious activity. In fact, these attacks enable outsiders to use legitimate functions to achieve their malicious aims.

A pertinent example is the use of malicious web scraping against APIs. While the threat of scraping is not new, identifying malicious scraping against APIs is tricky. LinkedIn recently saw the impact of this security weakness when an outsider compiled a dataset of 700 million LinkedIn users that included locations and phone numbers.

Pentests on APIs can help to flag any weaknesses related to the nature of API architecture that hackers are likely to exploit. For example, tests can identify cases of excessive data exposure, where too much information gets passed to client applications from an API. This can occur when developers rely on the client to filter data rather than setting up effective filtering at the API level.

4. Shared Development

There is frequently a shared development model in APIs where multiple parties or stakeholders collaborate in the design of an API. A niche SaaS app used by a few different businesses might have its API collaborated on by the app’s owner along with the businesses using it.

Such a situation is useful for tweaking an API until it provides the maximum utility for all parties involved, but shared development is also ripe for security misunderstandings. Important security tasks and checks might get missed because it has been assumed that another party was handling them. Before you know it, you have an API in production that doesn’t have any user authentication.

By simulating attacks on an API, a pen test helps to detect the vulnerabilities that may have slipped through the often convoluted process that is shared development.

5. Rapid Proliferation

The rapid proliferation of APIs creates a security issue in itself. Businesses commonly struggle to maintain a complete and accurate inventory of all APIs used within their digital ecosystem due to the pace at which new APIs get added and versions are updated. This inventory needs to include all third-party APIs too because they could pose security risks.

A lack of visibility can lead to zombie APIs that are mistakenly left unsecured and wide open to attack. Shadow APIs from third parties that aren’t documented can also easily slip under the radar and introduce further security risks. Penetration tests can help businesses keep better pace with API proliferation and uncover serious risks before it’s too late.

Call Security Pursuit for API Pentesting today

Security Pursuit’s certified, expert penetration testers can identify exploitable vulnerabilities using real-world hacking techniques on your APIs. You also get detailed evidence of findings along with step-by-step remediation. In a world where APIs are quickly becoming the most targeted component of your IT environment, it’s time to bring in the experts and shore up your defenses.

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