Auth0 Misconfigurations

1 Click Or 0-Click Account Takeover Due To Account Linking Misconfiguration In OAUTH

Account Takeover using "Log In with Google"Auth0 Community

0-Click

• The victim will create a account using the option “Log In with Google”

• The attacker creates an account using the same email and a new password

• Logged in Without confirmation

1-Click

• Victim will receive a email to confirm the account

• The attacker waits for the victim to click on the confirmation link and he will be able to log in using the password he set for the victim’s account

Self Registration in Loggin-Only Targets

How I Exploited an Auth0 Misconfiguration to Bypass Login RestrictionsMedium

• Intercept Login Requests:

  • Enter random login credentials (any email and password) on the login page and intercept the request with Burp Suite.

  • Inspect the request structure and headers to confirm that it resembles an Auth0 request.

• Modify the Request:

  • Send the intercepted login request to Burp Repeater.

  • Change the endpoint from /co/authenticate (or similar) to /dbconnections/signup.

  • Replace the username parameter with email, and set the realm parameter to connection.

  • Add parameters such as client_id, email, password, and connection if they’re not already present.

• Send the Request:

  • In Burp Repeater, send the modified request.

  • Check for a 200 OK response and a response body indicating account creation, such as {"_id":"<id>","email":"<your-email>","email_verified":false}.

• Test Access with New Credentials:

  • Use the credentials you specified in the signup request to attempt login on the application.

  • If successful, this confirms the misconfiguration, as you've bypassed the disabled signup restriction.

Account Linking Misconfiguration in Aouth-Logging-Only Targets

Exploiting Auth0 Misconfigurations: A Case Study on Account Linking VulnerabilitiesMedium

1. Identify the Social Login Mechanism:

   • Access the login page of the target application and check for any social login options, like "Sign up with Google."

   • Note the primary email address used during the social login (e.g., using [e-mail]).

2. Create an Account Using Social Login:

   • Use the available social login option (like Google) to create an initial user account on the application.

3. Intercept the Request to Identify the dbconnection:

   • Attempt to create a new account with the same email via the email/password method. If you encounter a failed response, intercept this request in Burp to analyze the dbconnection parameter.

   • Identify the correct dbconnection name for the application.

4. Craft a Signup Request with dbconnection:

   • Using Burp Repeater, send a POST request to the Auth0 /dbconnections/signup endpoint.

   • Modify the request as follows:

     POST /dbconnections/signup HTTP/2
     Host: auth.<target_domain>.com
     Content-Length: 224
     Content-Type: application/json
     Origin: https://auth.<target_domain>.com
     Referer: https://auth.<target_domain>.com/
     
     {
       "client_id": "XXXXXXXXXXXXXXXXXXXX",
       "email": "[e-mail]",
       "password": "testA@123",
       "connection": "app-prod-users",
       "credential_type": "http://auth0.com/oauth/grant-type/password-realm"
     }

5. Verify Account Creation and Linkage:

   • Submit the request with the correct dbconnection and client ID.

   • Check for a successful response indicating the account creation for the same email.

6. Test Access with Modified Authorization URL:

   • Try logging in with the newly created email/password by modifying the authorization URL to use dbconnection:

     https://auth.<target_domain>.com/authorize?client_id=<client_id>&response_type=token&connection=app-prod-users&prompt=login&scope=openid%20profile%20phone&redirect_uri=<redirect_uri>

   • Confirm if logging in with email/password redirects you to the original social login account, indicating an unintended account linkage.

Exploiting Email Normalization and Custom Database Configurations in Auth0 for Account Takeover

AuthC Under Siege: Innovative Approaches to Penetrate Authentication Across All Layers | NotionDeepStrike on Notion

1. Identify the Email Registration Endpoint:

   • Locate the target application's signup endpoint that uses Auth0, specifically for Email and Password authentication. This is where the potential vulnerability exists.

2. Create a Primary Account:

   • Register an account with an email like [e-mail] using a password such as Password123.

   • Confirm that you can log in with these credentials and access your account details.

3. Attempt Registration with a Unicode Variant:

   • Construct an email address with a visually similar Unicode character. For example, change i to a Unicode dotless or dotted variant:

     • Example: Change [e-mail] to vı[e-mail] (with a dotted or dotless "i").

   • Try to register a new account with this email variant and a different password like Password456.

4. Observe the Response:

   • If Auth0’s Get User Script does not normalize Unicode characters, it may allow the creation of this account without triggering a duplicate email error.

   • If the account creation is successful, Auth0 likely has a misconfiguration with email normalization.

5. Test for Account Credentials Overwrite:

   • Log in with the Unicode variant email (vı[e-mail]) using the password you set (Password456).

   • If this account gives you access to the original account details, Auth0’s Create User Script might be normalizing email addresses, leading to the overwriting of the original credentials.

6. Confirm Account Takeover:

   • Check if both email variants ([e-mail] and vı[e-mail]) can log in, especially if each set of credentials provides access to the same user data.

   • This behavior suggests that Auth0’s inconsistent email normalization is causing an account takeover scenario.