Application programming interfaces (APIs) are the connective tissue behind digital modernization, helping applications and databases exchange data more effectively. The State of API Security in 2024 Report from Imperva, a Thales company, found that the majority of internet traffic (71%) in 2023 was API calls. What’s more, a typical enterprise site saw an average of 1.5 billion API calls in 2023.
The expansive volume of internet traffic that passes through APIs should be concerning for every security professional. Despite best efforts to adopt shift-left frameworks and SDLC processes, APIs are often still pushed into production before they’re cataloged, authenticated, or audited. On average, organizations have 613 API endpoints in production, but that number is rapidly expanding as pressure grows to deliver digital services to customers more quickly and efficiently. Over time, these APIs can become risky, vulnerable endpoints.
In their report, Imperva concludes that APIs are now a common attack vector for cybercriminals because they’re a direct pathway to access sensitive data. As a matter of fact, a study from the Marsh McLennan Cyber Risk Analytics Center finds that API-related security incidents cost global businesses as much as $75 billion annually.
More API Calls, More Problems
Banking and online retail reported the highest volumes of API calls compared to any other industry in 2023. Both industries rely on large API ecosystems to deliver digital services to their customers. Therefore, it’s no surprise that financial services, which include banking, were the leading target of API-related attacks in 2023.
Cybercriminals use a variety of methods to attack API endpoints, but one common attack vector is Account takeover (ATO). This attack occurs when cybercriminals exploit vulnerabilities in an API’s authentication processes to gain unauthorized access to accounts. In 2023, nearly half (45.8%) of all ATO attacks targeted API endpoints. These attempts are often carried out by automation in the form of bad bots, software agents that run automated tasks with malicious intent. When successful, these attacks can lock customers out of their accounts, provide criminals with sensitive data, contribute to revenue loss, and increase the risk of non-compliance. Considering the value of the data that banks and other financial institutions manage for their customers, ATO is a concerning business risk.
Why Mismanaged APIs are a Security Threat
Mitigating API security risk is a unique challenge that frustrates even the most sophisticated security teams. The issue stems from the fast pace of software development and the lack of mature tools and processes to help developers and security teams work more collaboratively. As a result, nearly one out of every 10 APIs is vulnerable to attack because it wasn’t deprecated correctly, isn’t monitored, or lacks sufficient authentication controls.
In their report, Imperva identified three common types of mismanaged API endpoints that create security risks for organizations: shadow, deprecated, and unauthenticated APIs.
- Shadow APIs: Also known as undocumented or undiscovered APIs, these are APIs that are unsupervised, forgotten about, and/or outside of the security team’s visibility. Imperva estimates that shadow APIs make up 4.7% of every organization’s collection of active APIs. These endpoints are introduced for a variety of reasons—from the purpose of software testing to use as a connector to a third-party service. Issues arise when these API endpoints are not cataloged or managed properly. Businesses should be concerned about shadow APIs because they typically have access to sensitive information, but nobody knows where they exist or what they’re connected to. A single shadow API can lead to a compliance violation and regulatory fine, or worse, a motivated cybercriminal will abuse it to access an organization’s sensitive data.
- Deprecated APIs: Deprecating an API endpoint is a natural progression in the software lifecycle. As a result, the presence of deprecated APIs is not uncommon, as software is updated at a rapid, continuous pace. In fact, Imperva estimates that deprecated APIs, on average, make up 2.6% of an organization’s collection of active APIs. When the endpoint is deprecated, services supporting such endpoints are updated and a request to the deprecated endpoint should fail. However, if services are not updated and the API isn’t removed, the endpoint becomes vulnerable because it lacks the necessary patching and software update.
- Unauthenticated APIs: Often, unauthenticated APIs are introduced as a result of misconfiguration, oversight from a rushed release process, or the relaxation of a rigid authentication process to accommodate older versions of software. These APIs make up, on average, 3.4% of an organization’s collection of active APIs. The existence of unauthenticated APIs poses a significant risk to organizations as it can expose sensitive data or functionality to unauthorized users and lead to data breaches or system manipulation.
To mitigate the various security risks introduced by mismanaged APIs, conducting regular audits to identify unmonitored or unauthenticated API endpoints is recommended. Continuous monitoring can help detect any attempts to exploit vulnerabilities associated with these endpoints. In addition, developers should regularly update and upgrade APIs to ensure that deprecated endpoints are replaced with more secure alternatives.
How to Protect Your APIs
Imperva offers several recommendations to help organizations improve their API Security posture:
- Discover, classify, and inventory all APIs, endpoints, parameters, and payloads. Use continuous discovery to maintain an always up-to-date API inventory and disclose exposure of sensitive data.
- Identify and protect sensitive and high-risk APIs. Perform risk assessments specifically targeting API endpoints vulnerable to Broken Authorization and Authentication as well as Excessive Data Exposure.
- Establish a robust monitoring system for API endpoints to detect and analyze suspicious behaviors and access patterns actively.
- Adopt an API Security approach that integrates Web Application Firewall (WAF), API Protection, Distributed Denial of Service (DDoS) prevention, and Bot Protection. A comprehensive range of mitigation options offers flexibility and advanced protection against increasingly sophisticated API threats—such as business logic attacks, which are particularly challenging to defend against as they are unique to each API.