Does your organization rely on applications and APIs to power its digital services? A complex security threat is multiplying in volume and aims to exploit an application or API’s unique functionality. Most concerning, many businesses may not realize how vulnerable they are to these threats.
Business logic is the intended functionality and decision-making processes of an application. For example, if a customer orders more than five items, then they get a 15% discount. When programmed into software applications, this conditional logic automates business decisions and makes processes more efficient.
Unfortunately, business logic is increasingly targeted by bad actors as a means to gain unauthorized access or cause harm without triggering security alerts. In fact, 17% of all attacks on APIs in 2022 came from automated threats abusing business logic.
However, business logic itself is not the issue. The issue lies in the implementation of the business logic within the application. Risks emerge when multiple inputs and data-driven components are tied together through a web of APIs that are implemented without considering potential security vulnerabilities or misconfigurations.
To address the threats posed by business logic attacks, organizations must rethink their current security strategies for protecting applications and APIs, and the data they’re accessing.
What is a business logic attack?
Rather than targeting technical vulnerabilities, a business logic attack (BLA) exploits an application’s intended functionality and processes to manipulate workflows, bypass traditional security measures, and misuse legitimate features.
While business logic is well known to developers, it is less understood within the security community. Essentially, business logic is what dictates how an application operates. It’s a set of rules that determines how it interacts with users and other systems; but, as applications become increasingly complex over time, more rules are needed to dictate their behavior. This creates opportunities for abuse, as attackers are able to identify rules that they can manipulate to their advantage, leading to potential business losses or damages.
Given that business logic vulnerabilities are highly custom and specific to individual applications and APIs, there is not a common attack pattern for security leaders to monitor. Therefore, it’s impossible to apply a generic rule and assume all application and API deployments are secure. Complicating matters, an application without a business logic vulnerability today may become vulnerable in the next version after a change in the API implementation.
Three common ways business logic can be exploited are:
- Function misuse: Within an application, this exploits legitimate functions to perform malicious actions, such as issuing escalated privileges or granting access to unauthorized data.
- Security controls bypass: Alters the flow of an application to bypass security controls or engage in unauthorized actions.
- Cross-user data leakage: Exploits the input to an API in order to access data belonging to other users. This is difficult to prevent and can be extremely lucrative for attackers who are looking for sensitive information.
Many traditional security solutions, like web application firewalls (WAFs), are not designed to detect BLA activity. They rely on identifying known attack patterns and signatures. BLAs, however, are unique to each application. They are highly context-dependent, exploiting the specific logic of a given application. This makes it easy for BLAs to blend in with normal user traffic, especially since BLAs also lack other external indicators—such as malicious IPs or network traffic anomalies—that typically signify attack activity.
How to prevent business logic attacks
To successfully defend against BLAs, organizations should first understand their business logic and familiarize themselves with their application’s workflows, processes, and expected user behavior to identify potential weak points and vulnerabilities. If new functionality is being added to an application, thorough testing should be performed before that code is deployed to the production environment. When reviewing the code, organizations should pay particular attention to the input validation and ensure that only legitimate requests are processed. Even after the code has been deployed, tools like runtime application self-protection (RASP) and interactive application security testing (IAST) can help identify potential vulnerabilities as they arise, giving security teams the opportunity to address them in real time.
Organizations should also deploy anomaly and behavior-based analysis techniques to recognize abnormal patterns or sequences of actions. For example, a user visits an eCommerce platform and adds a large number of expensive items to their cart. While this is something that rarely happens for the business and it isn’t overtly malicious, it is uncommon and worth monitoring. By understanding the expected behavior of an application or its users and employing detection algorithms, businesses can identify and flag suspicious interactions that indicate potential BLAs.
Additionally, organizations should limit the scope of their APIs and implement access controls based on user roles to minimize potential damage in the event of a successful attack. One effective strategy for this is the principle of least privilege (POLP). This principle advocates for a user to be given the minimum levels of access, or privileges, required to perform their tasks.
With the majority of attacks now coming from automated threats, and a growing number of those attacks target business logic via APIs, traditional signature-based defenses are insufficient to stop targeted BLAs on their own. Ultimately, a multi-layered approach capable of scanning for vulnerabilities, monitoring behavior, and protecting websites, applications, and APIs from BLA activity is essential. Augmenting WAF platforms with bot management and API security solutions is imperative to be able to effectively identify attack activity, even when it does not conform to known attack signatures.
Don’t let business logic attacks damage your business
As applications grow more complex, attackers will increasingly seek to exploit vulnerabilities in business logic to bypass traditional security measures and gain unauthorized access. BLAs can be a highly effective way for attackers to steal sensitive data—including personal details, financial information, and healthcare data—and with the cost of breaches continuing to rise, organizations need to ensure they are adequately protected. While solutions like a WAF are still an essential element of application security, they are not equipped to defend against BLAs. Businesses need to act now and invest in security solutions that can identify and stop sophisticated automation that targets APIs and application business logic.
