Basic HTTP authentication

Overview of Basic HTTP Authentication:

• Basic HTTP Authentication (Basic Auth) is a simple method used by web applications to secure sensitive data and functionalities.

• It operates as a challenge-response protocol where the server requests user credentials before granting access to protected resources.

• When a user tries to access a restricted area, the server responds with a 401 Unauthorized status and a WWW-Authenticate header, prompting the browser to display a login dialog.

How Basic Auth Works:

1. The user enters their username and password.

2. The browser concatenates the credentials into a single string in the format username:password.

3. This string is encoded using Base64 and included in the Authorization header of subsequent requests, formatted as Basic <encoded_credentials>.

4. The server decodes the credentials, verifies them against its database, and either grants or denies access.

Example of Basic Auth in HTTP GET Request:

GET /protected_resource HTTP/1.1
Host: www.example.com
Authorization: Basic YWxpY2U6c2VjcmV0MTIz

Exploiting Basic Auth with Hydra:

• To demonstrate brute-forcing Basic HTTP Authentication, we will use Hydra with the http-get service.

Setup:

1. Download Wordlist (if needed):

   curl -s -O https://raw.githubusercontent.com/danielmiessler/SecLists/refs/heads/master/Passwords/Common-Credentials/2023-200_most_used_passwords.txt

2. Hydra Command:

   hydra -l basic-auth-user -P 2023-200_most_used_passwords.txt 127.0.0.1 http-get / -s 81

Command Breakdown:

• -l basic-auth-user: Specifies the username for the login attempt.

• -P 2023-200_most_used_passwords.txt: Indicates the password list file to use for the brute-force attack.

• 127.0.0.1: The target IP address (localhost in this case).

• http-get /: Specifies that the target service is an HTTP server and the attack should be performed using HTTP GET requests to the root path (/).

• -s 81: Overrides the default HTTP port and sets it to 81.

Execution:

• Upon running the command, Hydra will systematically attempt each password from the specified list against the Basic Auth login.

• Eventually, it will identify the correct password for basic-auth-user, allowing access to the protected resource and enabling the retrieval of the flag.

Conclusion:

• Basic HTTP Authentication is straightforward but vulnerable to brute-force attacks. Tools like Hydra can efficiently exploit these vulnerabilities, highlighting the importance of using stronger authentication methods and implementing security best practices.