Web applications are crucial elements in the provision of services on the internet.

It's no longer news that many have suffered from security vulnerabilities. A website can expose individuals to significant risk if it's not properly protected.

Attackers can access restricted pages and confidential user data using several techniques, including forced browsing.

In this article, we shall discuss the concept of forced browsing and how it works.

What Is Forced Browsing?

Cyber Attacker

Forced browsing is a technique used by attackers to gain access to restricted web pages, or other resources, by manipulating the URL. It is also referred to as forceful browsing. Just as the name implies, an attacker is forcefully browsing a resource that they don't have authorization for.

Such an attack targets files in the webserver directory, or restricted URLs, that don't check for authorization.

These resources are profitable to attackers if they contain sensitive data. It could be about the website itself or the site's customers. Sensitive data might include:

  • Credentials
  • Source code
  • Backup files
  • Logs
  • Configuration
  • Internal network details

If a website can fall victim to a forced browsing attack then it isn’t properly secure.

Authorization should ensure that users have appropriate permission to access restricted pages. Users provide their login details, like a username and password, before they're allowed access. Forced browsing tries to bypass these security settings by requesting access to restricted paths. It tests to see if it can access a page without providing valid credentials.

How Does Forced Browsing Work?

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Forced browsing is a common problem with websites that have various user roles such as normal users and admin users. Each user logs in from the same page but has access to different menus and options. However, if the pages those menus lead to aren't secure, a user might guess the name of a valid page and try to access its URL directly.

Several scenarios show how forced browsing works, whether it's done manually or with the use of an automated tool. Let's take a look at some instances.

1. An insecure account page

A user logs in to a website and the URL for their account page is www.example.com/account.php?user=4. The user can proceed to do a number rotation and change the URL to www.example.com/account.php?user=6. If the page opens, they'll be able to access the other user's information without needing to know their login details.

2. An insecure order page

A user with an account on an e-commerce website views one of their orders at www.example.com/orders/4544. They now change the order ID randomly to www.example.com/orders/4546. If the orders page has a forced browsing weakness, the attacker might discover details of the user with that order. At the very least, they'll retrieve information about an order that isn't theirs.

3. URL scanning

An attacker makes use of a scanning tool to search for directories and files in the web server's filesystem. It might scan for common names of admin, password, and log files. If the tool gets a successful HTTP response, it implies that a matching resource exists. Then the attacker will go ahead and access the files.

Forced Browsing Methods

Lady on Tablet

An attacker can carry out a forced browsing attack manually or with automated tools.

In manual forceful browsing, the attacker uses the number rotation technique, or correctly guesses the name of a directory or file and types it into the address bar. This method is harder than the use of automated tools because the attacker cannot manually send requests at anything like the same frequency.

Forced browsing with the help of automated tools involves using a tool to scan for existing directories and files on the website. Many restricted files are usually hidden but scanning tools can fish them out.

Automated tools scan through many potential page names and record the results obtained from the server. They also store the URLs that correspond with each page request. The attacker will go on to carry out a manual investigation to discover which pages they can access.

With either method, forced browsing is like a brute force attack, where the attacker guesses your password.

How to Prevent Forced Browsing

Cybersecurity Lock

Here's something to bear in mind: hiding files doesn't make them inaccessible. Make sure you don't assume that, if you don't link to a page, an attacker can't access it. Forced browsing debunks this assumption. And common names assigned to pages and directories can be easily guessed, making resources accessible to attackers.

Here are some tips to help you prevent forced browsing.

1. Avoid the Use of Common Names for Files

Developers typically allocate common names to files and web directories. These common names might be "admin", "logs", "administrator", or "backup". Looking at them, they're quite easy to guess.

One way to keep forced browsing at bay is to name files with strange or complex names that are hard to figure out. With that in place, attackers will have a hard nut to crack. The same technique helps with creating strong and effective passwords.

2. Keep Your Directory Listing Off on the Webserver

A default configuration poses a security risk as it could aid hackers to gain unauthorized access to your server.

If you enable directory listing on your web server, you can leak information that will invite attackers. You should turn off your directory listing and keep filesystem details away from public view.

3. Verify User Authentication Before Each Secured Operation

It's easy to disregard the need for authenticating site users on a specific web page. If you're not careful, you might forget to do so.

Ensure that your web pages are accessible only to authenticated users. Deploy an authorization check at every step to maintain security.

4. Use Proper Access Controls

Using proper access controls involves granting users explicit access to resources and pages that correspond with their rights and nothing more.

Ensure you define the types of files that users have permission to access. For instance, you can restrcit users from accessing backup or database files.

Go Head to Head With Attackers

If you host a web application on the public internet, you're inviting attackers to try their best to force their way in. With this in mind, forced browsing attacks are bound to happen. The question is: will you allow attackers to gain access when they attempt to?

You don't have to. Put up a strong resistance by deploying different layers of cybersecurity on your system. It's your responsibility to secure your digital assets. Do whatever you have to do to secure that which belongs to you.