Gửi #886159: itsourcecode Payroll System 1.0 Unrestricted Upload

Description:
The `save_settings()` function handles file uploads with zero validation. No extension allowlist, no MIME type verification, no content inspection. Uploaded files retain their original filename and extension, and are stored in the web-accessible `assets/img/` directory. Combined with missing authentication (VULN-01), an unauthenticated attacker can upload and execute arbitrary PHP code.

Vulnerable Code:
**File**: `admin_class.php`, Lines 100-129
```php
function save_settings(){
extract($_POST);
$data = " name = '".str_replace("'","’",$name)."' ";
$data .= ", email = '$email' ";
$data .= ", contact = '$contact' ";
$data .= ", about_content = '".htmlentities(str_replace("'","’",$about))."' ";
if($_FILES['img']['tmp_name'] != ''){
$fname = strtotime(date('y-m-d H:i')).'_'.$_FILES['img']['name'];
$move = move_uploaded_file($_FILES['img']['tmp_name'],'assets/img/'. $fname);
$data .= ", cover_img = '$fname' ";
}
// ...
}
```
- No extension allowlist
- No MIME type validation (`getimagesize()`, `finfo`)
- No file content inspection
- Original filename and extension preserved (`$_FILES['img']['name']`)
- Files stored in web-accessible `assets/img/`

Proof of Concept:
**Upload PHP webshell**:
```http
POST /ajax.php?action=save_settings HTTP/1.1
Host: localhost:8093
Content-Type: multipart/form-data; boundary=----Boundary

Impact:
- Remote Code Execution on the web server
- Complete server compromise
- Data exfiltration, malware deployment, lateral movement
- Zero authentication required — fully unauthenticated RCE

Reference: https://github.com/microwaveabi/vul/issues/12

• Nguồn: ⚠️ https://github.com/microwaveabi/vul/issues/12
• Người dùng: microwave (UID 96185)
• Đệ trình: 11/07/2026 05:17 (cách đây 2 các tháng)
• Kiểm duyệt: 24/08/2026 00:50 (1 month later)
• Trạng thái: được chấp nhận
• Mục VulDB: 394579 [itsourcecode Payroll System 1.0 admin_class.php save_settings img nâng cao đặc quyền]
• điểm: 20