Business Logic Abuse — Exploiting the Rules of the Game — API Security

As Cybersecurity Awareness Month continues, we wanted to dive even deeper into the attack methods affecting APIs.

We’ve already reviewed Broken Object Level Authentication (BOLA), injection attacks, and authentication flaws; this week, we’re exploring business logic abuse (BLA). 

Unlike technical flaws, business logic flaws exploit how an API is designed to behave. They are difficult to catch because there are no security controls monitoring “approved” behaviors, so they must be caught more creatively.

Which means that security teams without anomaly detection have their work cut out for them. 

This is what we will touch upon:

What Is Business Logic Abuse

Business logic abuse occurs when attackers misuse a system’s (in this case, an API) intended functionality to get it to do things it wasn’t designed to do. These are things that it technically could do, however, because of design flaws and oversights. 

Instances of BLAs in APIs include:

• Bypassing workflow steps, like skipping the payment page.
• Data manipulation, like altering the price of items on the website.
• Violating business rules, like exceeding the coupon limit.
• Exploiting authentication gaps to escalate privileges.
• Session hijacking by exploiting sessions that didn’t expire correctly.

The list goes on.

How API Business Logic Abuse Works in the Real World

According to the most recent Wallarm Q2 2025 API ThreatStats Report, BLAs were largely to blame for the nearly 10% rise in API vulnerabilities over the previous quarter. Within the past year, attacks rose significantly within financial and retail APIs. 

As Wallarm’s CEO, Ivan Novikov, noted, “Attackers are no longer just scanning for outdated libraries; they’re exploiting the ways APIs behave, especially those powering AI systems and automation.” 

So, what does business logic abuse look like in these sectors? Here are a few real-world examples. 

API Skimming in Retail

This year, researchers discovered an attack on the popular payment processing API, Stripe. The Stripe API skimming campaign is a fine illustration of Business Logic Abuse in action, where attackers exploited a deprecated API intended for legitimate payment validation. Instead of a coding flaw, they abused the API’s intended logic to verify stolen card details, turning a normal business process into a tool for fraud—highlighting how valid functionality can be maliciously repurposed.

API Sign-Up Abuse in a Fast Food Chain

In the Burger King incident, ethical hackers abused RBI’s “open signup” API and GraphQL mutation to self-register, bypass email verification, and escalate privileges to admin. They then accessed drive-thru audio, internal store systems, and employee data — turning legitimate signup and role-management logic into a vector for deep internal compromise.

API Ticketing Abuse for Popular Events

In another case being investigated by FTC, resellers abused legitimate purchase APIs to exceed ticket purchasing limits for many popular events, including Taylor Swift’s Eras Tour, and resell the tickets at significantly higher prices, generating millions in revenue. They circumvented protections (e.g., per-account/credit card limits, SMS verification) using fake accounts, virtual cards, proxies, and SIM boxes. They turned Ticketmaster’s intended controls into a tool for mass acquisition and resale, subverting business logic meant to enforce fairness.

Challenges to Detection

Attackers are leaning into business application attacks because catching them is something that takes uncommon knowledge and expertise. 

Wallarm Security Strategist Tim Erlin explains that “finding vulnerabilities is important, but so is detecting attacks as they happen. They’re two sides of the same coin, and both require that understanding of normal application logic.” As he told TechNadu, detecting BLAs requires a deep understanding of business logic, and that’s not something everybody has.

Another challenge to API BLA detection is that APIs’ status as “internal tools” makes them automatically seem more secure. Therefore, they are less protected in practice. What security teams need to recognize, Erlin says, is that “internal tools are often accessible externally or through other external tools.”

These challenges, lack of business logic expertise and a false sense of security, contribute to BLAs’ recent rise in scope and success. 

Mitigating Business Logic Abuse in APIs with Wallarm

Wallarm provides advanced protection for APIs by focusing on the logic layer where traditional security tools often fail. The platform combines API discovery, specification enforcement, and AI-driven behavioral analysis to understand how APIs are designed to operate and detect when they deviate from that intent. By continuously analyzing traffic patterns and enforcing logical consistency, Wallarm stops attackers from exploiting weaknesses in workflows, transitions, or process rules that can lead to fraud or data manipulation. For example:

• Behavioral Anomaly Detection – Uses AI to identify deviations from normal API interaction patterns, blocking requests that violate expected workflows or parameter logic. This helps stop fraud attempts and misuse before they propagate through the system.
• Flow Order Enforcement – Ensures that API calls occur in the correct sequence, preventing attackers from bypassing intermediate steps or triggering operations out of order. This defends against logic abuses like premature transaction completion or skipping authentication steps.
• Specification Enforcement – Validates every request against an approved OpenAPI schema, ensuring that parameters, data types, and endpoints conform to intended design. This blocks attempts to exploit hidden or deprecated functionality.

Wallarm delivers protection where business processes and security intersect. Its combination of runtime visibility, behavioral intelligence, and precise specification validation enables security teams to detect and block subtle abuses that target workflow design rather than code vulnerabilities. With Wallarm, organizations can ensure their APIs behave as intended, protect revenue and customer trust, and prevent logic-based attacks before they cause harm.

Secure the APIs that underpin your revenue. Protect against emerging API threats, including the OWASP Business Logic Abuse Top 10, with Wallarm.

Business logic is unique to every API, so protection must adapt too. Check out Wallarm’s Advanced API Security to see adaptable, end-to-end API defense in action.