> For the complete documentation index, see [llms.txt](https://n3t-hunt3r.gitbook.io/pentest-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://n3t-hunt3r.gitbook.io/pentest-book/web-application-pentesting/registration-vulnerabilities.md).

# Registration Vulnerabilities

## Registration Vulnerabilities

### Takeover

### Duplicate Registration

* Try to generate using an existing username
* Check varying the email:
  * uppsercase
  * +1@
  * add some some in the email
  * special characters in the email name (%00, %09, %20)
  * Put black characters after the email: `test@test.com a`
  * victim@<gmail.com@attacker.com>
  * victim@<attacker.com@gmail.com>

#### Username Enumeration

Check if you can figure out when a username has already been registered inside the application.

#### Password Policy

Creating a user check the password policy (check if you can use weak passwords).\
In that case you may try to bruteforce credentials.

#### SQL Injection

\*\*\*\***Check this page** to learn how to attempt account takeovers or extract information via **SQL Injections** in registry forms.

#### Oauth Takeovers

{% page-ref page="oauth-to-account-takeover.md" %}

#### SAML Vulnerabilities

{% page-ref page="saml-attacks/" %}

#### Change Email

when registered try to change the email and check if this change is correctly validated or can change it to arbitrary emails.

### More Checks

* Check if you can use **disposable emails**
* **Long** **password** (>200) leads to **DoS**
* **Check rate limits on account creation**
* Use username@**burp\_collab**.net and analyze the **callback**