Protecting Against Business Logic Attacks in Web Applications

Protecting your web applications from attacks is essential to having a secure online presence. The most dangerous threats are often the most subtle, disguised as legitimate actions and transactions. These are referred to as business logic attacks and can cause substantial harm if not prevented. This article will explain what business logic attacks are, the most common types you might encounter, and how to protect your web applications from them. Let’s dive in.

What are Business Logic Attacks?

A recent study found that “bad bots” who exploited business logic accounted for 17% of all API attacks. This statistic highlights the increasing sophistication of cyber threats targeting web applications.

Business logic attacks are a type of security threat where an attacker exploits the normal operation of a web application to accomplish malicious goals. These attacks target an application’s ‘business logic’, which is the set of rules and procedures that govern how it operates. Unlike other attacks, they are not based on technical flaws or coding errors. Instead, they take advantage of the app’s legitimate features. This makes them especially insidious and difficult to detect, as they frequently mimic authentic user activities within the system.

Imagine a scenario where you own an online store that offers discounts for bulk purchases. An attacker could exploit this feature by placing a large order to get the discount, then canceling part of the order while keeping the reduced price. This causes financial loss from the sale, disrupts inventory management, and can potentially affect the pricing strategy of future orders. This is a simple example of a business logic attack.

The threat lies not in the vulnerability of your system but in manipulating its logic. Such manipulations can erode customer trust and tarnish the company’s reputation, making it imperative for businesses to implement robust controls to detect and mitigate these types of attacks.

Common Business Logic Attacks

Account takeovers, fraudulent transactions, and supply chain attacks are some of the most common business logic attacks.

An account takeover is a business logic attack where a hacker accesses a user’s account by leveraging features such as password recovery or account update functions. Once inside, the attacker can conduct unauthorized transactions, access sensitive data, or even lock out the actual user, causing financial and reputational harm to the individual and the organization.

For example, if your app sends a password reset link to an unverified email address, an attacker could intercept the link and gain access to the account. Similarly, suppose an application does not have adequate rate-limiting for login attempts or does not use CAPTCHA verification. In such cases, attackers will find it easier to guess passwords via brute force or automated scripts, raising the risk of account takeover.

Fraudulent transactions involve using the transaction process to gain an unfair advantage. An attacker can use a race condition, in which the order of operations affects the outcome, to make purchases without paying for them. This manipulation not only results in financial losses for businesses but it also undermines the integrity of the transaction system, eroding user trust and potentially leading to a loss of customer loyalty over time.

For instance, attackers could initiate two transactions simultaneously: one to purchase an item and another to withdraw funds for payment. If the purchase is processed before the withdrawal, they receive the item without paying for it. Attackers can also use promotional codes or vouchers in unexpected ways, such as applying them multiple times via race conditions or other vulnerabilities, amplifying the financial damage and exploiting the system beyond its intended purpose.

In a supply chain attack, an attacker compromises a third-party component of your web application to gain access to your system or data. This could be a library, a plugin, or any other external resource your application relies on. By exploiting vulnerabilities in these components, attackers can bypass your security measures and carry out their malicious activities.

In a recent supply chain attack, hackers infiltrated a network management solutions company’s development environment, embedding malicious code in the company’s software updates. Unaware of the compromise, organizations worldwide installed these corrupted updates, allowing attackers unauthorized system access. The breach demonstrates the extent to which vulnerabilities in third-party components can cause widespread security risks and data breaches that affect a wide range of systems.

Protecting Against Business Logic Attacks

To prevent business logic attacks, you must first thoroughly understand your web application and business rules. You need to identify potential areas of manipulation and put in place safeguards to detect and prevent it. This requires meticulous design, testing, and continuous monitoring of your application.

One of the most effective ways to secure your web applications is to use strict input validation. All user inputs should be validated and sanitized to prevent malicious manipulation. For example, if your application allows users to place bulk orders for discounts, ensure the number of items ordered matches the total price.

Some other best practices to prevent business logic attacks:

Regularly review and update business logic rules to address new threats and operational changes.
Enforce strong authentication and session management to prevent account takeovers. This could include multi-factor authentication, session timeouts, and secure password recovery procedures.
Use secure coding practices to reduce technical vulnerabilities that attackers can exploit. This includes input validation, output encoding, proper error handling, and secure configuration.
Regularly test your web application for business logic vulnerabilities. This can be accomplished through manual testing, automated testing, or a combination of the two.
Monitor your app for suspicious activity. Anomalies in user behavior or transaction patterns could indicate a business logic attack.

Protecting against business logic attacks is a continuous process that requires vigilance, awareness, and proactive strategies. Understanding your web application’s business logic, identifying potential vulnerabilities, and implementing the best practices outlined above can assist you in decreasing the risk of these subtle but dangerous attacks. Remember that web application security is about more than just protecting your data and systems; it also involves maintaining your users’ trust and confidence.

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Bogdan Sandu

Bogdan is a seasoned web designer and tech strategist, with a keen eye on emerging industry trends.

With over a decade in the tech field, Bogdan blends technical expertise with insights on business innovation in technology.

A regular contributor to TMS Outsource's blog, where you'll find sharp analyses on software development, tech business strategies, and global tech dynamics.