Guarding Against Price Manipulation: Top 5 Vulnerabilities in E-Commerce Websites

Price manipulation vulnerabilities in e-commerce websites are security weaknesses that allow malicious users to alter the price of products or services offered online, often to their advantage. These vulnerabilities can lead to significant financial losses for businesses and damage their reputation. Below are the five most common price manipulation vulnerabilities found in e-commerce websites, along with code examples illustrating how these vulnerabilities might manifest and suggestions for mitigating them.

1. Client-Side Price Manipulation

Vulnerability Description:

Client-side price manipulation occurs when the price of an item is determined or modified on the client's side (e.g., in the browser) without proper server-side validation.

<form action="/purchase" method="post">

    Product ID: <input type="text" name="product_id" value="123">

    Price: <input type="text" name="price" value="100"> <!-- Vulnerable to manipulation -->

    <input type="submit" value="Purchase">

</form>

Mitigation:

Ensure that the price is validated server-side using a trusted source (e.g., database) rather than relying on client-side input. Always re-fetch the price on the server side based on the product ID during the purchase process.

2. Hidden Field Manipulation

Vulnerability Description: Similar to client-side manipulation but involves hidden fields in forms where the price or other critical transaction details are stored and can be altered using browser developer tools. <form action="/purchase" method="post"> <input type="hidden" name="price" value="100"> <!-- </form>

Mitigation: Never store prices or sensitive transaction details in hidden form fields. Always rely on server-side validation to ensure integrity.

3. URL Tampering

Vulnerability Description: Occurs when the application uses URLs to pass important parameters, such as prices, that users can modify.

GET /purchase?product_id=123&price=100

Mitigation: Avoid passing sensitive transaction details like prices in URLs. Always validate and set prices on the server side based on product ID or other secure references.

4. Cookie Manipulation

Vulnerability Description: Websites sometimes store pricing information in cookies, which are stored on the client side and can be modified.

Code Example: JavaScript code that sets a price in a cookie:

document.cookie = "price=100; path=/";

Mitigation: Do not store sensitive pricing information in cookies. If you must use cookies for non-sensitive data, ensure that any critical data validation or verification occurs server-side.

5. Direct Object Reference (IDOR)

Vulnerability Description: An attacker manipulates direct object references to access unauthorised data. For example, by changing a product ID in a query, they could access another product at a lower price.

Code Example: URL or request that includes a direct reference to a product:

GET /purchase?product_id=123&price=100

Mitigation: Implement proper access control checks and validation mechanisms to ensure that users can only access or modify data that they are authorized to. Use indirect object references or UUIDs that are not easily guessable.

General Mitigation Strategies:

• Server-Side Validation: Always validate data on the server side. Do not rely solely on client-side validation.

• Use Sessions or Tokens: Store critical information on the server and associate it with the user's session or a secure token.

• Logging and Monitoring: Implement logging and monitoring to detect unusual activities that could indicate attempts at price manipulation.

• Regular Security Audits: Conduct regular security audits and penetration tests to identify and mitigate vulnerabilities.
  

Addressing these vulnerabilities requires a comprehensive approach that includes secure coding practices, rigorous testing, and ongoing monitoring to protect against price manipulation attacks.