API Threat Trends: How Attackers Are Exploiting Business Logic

As businesses rely more on APIs, attackers are quick to turn that trust into opportunity. Among the most dangerous and difficult-to-detect threats are business logic exploits, which let cybercriminals manipulate legitimate functionality to gain unauthorized access, exfiltrate data, or disrupt operations. These attacks often slip past traditional defenses unnoticed, making them a growing concern for security teams. In this blog, we’ll break down the latest trends in API abuse, focusing on business logic attacks, and show how Wallarm helps you stay one step ahead.

Understanding the New API Threat Paradigm

Traditional security solutions, like web application firewalls and intrusion detection systems, are designed to spot common API threats like SQL injection, cross-site scripting (XSS), and other known vulnerabilities – and they do so extremely effectively. However, when it comes to business logic abuse, these defenses often fall short. 

Unlike straightforward code injection or command execution attacks, business logic vulnerabilities require a deep understanding of an application’s intended workflows. Traditional solutions lack this understanding, typically being unaware of an API’s business context – who the user is, what roles exist, and which endpoints are legitimate for different user profiles. 

Attackers capitalize on this lack of understanding, subtly manipulating API calls to avoid detection. Instead of triggering obvious alerts with high-volume attacks, they stealthily alter the sequence or parameters of API requests. As a result, they can carry out malicious actions – like bypassing authentication or modifying transactions – without being detected by traditional tools. 

While we’re not there yet, OWASP is working on a top 10 for Business Logic Abuse. You can check out the project and even contribute here. 

Business Logic API Threats in the Real World

Banking Sector: OTP Flooding and Account Takeover

Financial institutions use APIs to deliver one-time passwords (OTPs) and offer an extra layer of security. However, attackers can flood endpoints with requests to disrupt legitimate transactions or even force a temporary lockout. If the authentication mechanism fails to distinguish between legitimate and automated traffic – as is typical with traditional solutions – attackers can leverage the weakness to execute a total account takeover. 

Retail Sector: Payment Processing API Skimming

E-commerce platforms rely on intricate API calls to manage the checkout process, including item validation, pricing computation, and payment processing. Earlier this year, researchers at Jscrambler uncovered a new skimming attack that exploits the Stripe API – a popular payment processing API – to steal payment information. Unlike traditional skimming attacks that insert fake payment forms, attackers used the legitimate Stripe AI to siphon off data in real-time, injecting JavaScript directly into checkout pages and capturing credit card details before they reach Stripe’s secure processing system. 

Gaming and Digital Rewards: Exploiting In-Game Economy APIs

APIs play a crucial role in the modern gaming industry, and they are used to manage in-game currencies, rewards, and progression systems. But when these APIs fail to enforce strict business logic, attackers can manipulate the order or parameters of API calls to gain unauthorized benefits, such as acquiring extra virtual currency, unlocking premium features, or bypassing in-game spending. 

Transportation and Ridesharing: Surge Pricing Exploitation

Ridesharing platforms use APIs to handle ride requests, pricing, and driver matching. Attackers can abuse these APIs by sending artificial ride requests from multiple accounts or devices, tricking the system into interpreting requests and genuine demand surges, and triggering surge pricing algorithms. 

How Wallarm Mitigates Business Logic API Threats

Contextual and Session Analysis

Contextual awareness is crucial for mitigating business logic abuse. Wallarm gains this context by reconstructing entire sessions rather than examining individual requests in isolation. Understanding the natural progression of API calls in normal business operations allows the platform to recognize when attackers try to bypass critical checks or reorder actions. 

Moreover, our platform uses machine learning and statistical techniques to establish a baseline of normal behavior for key API endpoints. With this information, we calculate scores – such as the business logic score – that quantify how frequently a client interacts with sensitive parts of an application. If an attacker attempts to manipulate this flow – such as by submitting out-of-order or atypical requests – those anomalies are flagged as suspicious. 

Multi-Stage Parsing and Adaptive Rule Engine

Wallarm’s multi-stage approach to parsing breaks down each API request in layers—from raw HTTP elements to deeply encoded payloads—to uncover not only classic injection signatures but also more subtle changes in request behavior that might indicate an abuse of business logic. Moreover, Wallarm’s platform allows security teams to deploy custom rules tailored to the specifics of their application’s logic. This means that if a business workflow is prone to certain types of abuse, security teams can refine rules accordingly.

Automated Endpoint Discovery and Protection

Wallarm’s API Discovery module automatically catalogs all endpoints, paying special attention to those that power critical business functions, like authentication, billing, or transaction processing. This capability helps pinpoint which parts of the API are at higher risk of business logic abuse. 

Real-Time Mitigation and Reporting

When Wallarm detects an attack, the platform automatically launches remediation actions like blocking malicious requests or rate-limiting offending IP addresses. Using dynamic, real-time mitigation significantly reduces the risk of successful exploitation. What’s more, the platform offers detailed dashboards and session analytics that not only alert security teams to potential abuses but also provide the information necessary to adjust security policies and respond to new attack patterns. Want to find out more about Wallarm’s approach to API abuse prevention? Click here.

The post API Threat Trends: How Attackers Are Exploiting Business Logic appeared first on Wallarm.

*** This is a Security Bloggers Network syndicated blog from Wallarm authored by Tim Erlin. Read the original post at: https://lab.wallarm.com/api-threat-trends-how-attackers-exploite-business-logic/