GitHub Security Advisory: GHSA-q3qx-cp62-f6m7
Package: getgrav/grav (COMPOSER)
Severity: MODERATE (CVSS 6.5)
CWE: CWE-204: Observable Response Discrepancy
Vulnerable versions: < 1.8.0-beta.27
Patched in: 1.8.0-beta.27

Summary: Grav Admin Plugin vulnerable to User Enumeration & Email Disclosure

Details:
# Grav v1.7.49.5 / Admin v1.10.49.1 – User Enumeration & Email Disclosure

### Summary
A **user enumeration and email disclosure vulnerability** exists in Grav **v1.7.49.5** with Admin plugin **v1.10.49.1**.  
The "Forgot Password" functionality at `/admin/forgot` leaks information about valid usernames and their associated email addresses through distinct server responses.  
This allows an attacker to enumerate users and disclose sensitive email addresses, which can be leveraged for targeted attacks such as password spraying, phishing, or social engineering.  

### Details

The issue resides in the [`taskForgot()`](https://github.com/getgrav/grav-plugin-admin/blob/6d673fc7c4f6962756f93ae651371e81f7f20924/classes/plugin/Controllers/Login/LoginController.php#L349) function, which handles the forgot password workflow.  
Relevant vulnerable logic:

```php
if (null === $user || $user->state !== 'enabled' || !$to) {
    ...
    // Generic message for invalid/non-existing users
    $this->setMessage($this->translate('PLUGIN_ADMIN.FORGOT_INSTRUCTIONS_SENT_VIA_EMAIL'));
    return $this->createRedirectResponse($current);
}

if ($rateLimiter->isRateLimited($username)) {
    ...
    $interval = $config->get('plugins.login.max_pw_resets_interval', 2);

    // Sensitive message for valid users
    $this->setMessage($this->translate('PLUGIN_LOGIN.FORGOT_CANNOT_RESET_IT_IS_BLOCKED', $to, $interval), 'error');

    return $this->createRedirectResponse($current);
}
```

When an attacker submits the password reset form at `/admin/forgot` with an **invalid username**, the application responds with:  

```
Instructions to reset your password have been sent to your email address
```

However, when a **valid username** is supplied, and the attacker repeatedly triggers password reset requests, the application responds with:  

```
Cannot reset password for <USER_EMAIL>, password reset functionality temporarily blocked, please try later (maximum 60 minutes)
```

This discrepancy in responses enables:  
1. **User Enumeration** – Attackers can determine if a username exists in the system by analyzing the response.  
2. **User Email Disclosure** – The system discloses the actual email address associated with the account (e.g., `admin@localhost.test`).  

This violates best practices for authentication flows, where responses should remain generic to avoid leaking sensitive information.

### PoC
1. Navigate to the **Forgot Password** page:  `https://<target>/admin/forgot`
1. Submit a reset request with a random/invalid username (e.g., `invalid_user`):  

- Response:  
  ```
  Instructions to reset your password have been sent to your email address
  ```
3. Submit a reset request with a valid username (e.g., `admin`).  
4. Repeatedly request a reset for the same username until the lockout mechanism triggers.  
- Response:  
  ```
  Cannot reset password for admin@localhost.test, password reset functionality temporarily blocked, please try later (maximum 60 minutes)
  ```
5.