What do you know about Forced browsing (URL-based attack)

Forced browsing is a type of web application vulnerability that often goes unnoticed. Despite its simplicity, this vulnerability can lead to serious security threats for both individuals and organizations. In this blog post, we will delve into the details of forced browsing, how it works, and what you can do to protect your web applications. Whether you're a developer, security professional, or just someone looking to improve your online security, this article is for you.

What is Forced Browsing ?

Forced browsing is a type of attack in which an attacker gains access to sensitive information by guessing the URL or using a commonly known URL pattern. This is made possible due to poor design of a web application or API.

Vulnerabilities Types of Forced Browsing

There are various types of vulnerabilities in business logic that allow forced browsing to occur. These are caused by the following security weaknesses during the design or coding phase of an application:

• Believing that hiding information (in this case, a URL) behind a complex identifier is sufficient protection.
• Using common and easily guessed directory names, such as "/admin/", "/config/", or "/backup/".
• Neglecting to implement, activate, or effectively test authentication for all access to URLs or directories containing sensitive information.

How to detect forced browsing vulnerabilities?

Forced browsing is not a specific vulnerability like SQL injection or XSS. It can result from various insecure authentication practices in an application or API.

How to prevent forced browsing attacks?

To prevent forced browsing attacks, developers should never assume that simple solutions are good enough for application data security:

• Never assume that a publicly accessible URL is impossible to find because it’s not linked or indexed. If it exists, it can be found, so authentication is always a must.
• Never assume that once the user is authenticated, they are a valid user and don’t need any other access control. For every web page and API endpoint that is accessed, developers must ensure that authenticated users also require authorization to access data or resources. Otherwise, they risk introducing an IDOR vulnerability.

Even less experienced developers can usually avoid these basic errors by using common frameworks for web application and API development. Used correctly, these effectively enforce authentication and access control.