Performance Issues

How can I resolve the 403 Forbidden error returned by the server, which also states: "Access to this resource on the server is denied!"?

I'm facing an issue where submitting a form containing code examples (e.g., JavaScript or PHP) through my website that triggers a 403 Forbidden error with the message: "Access to this resource on the server is denied!" The form works fine when I submit text-only content, but when code is included in the form's text area, the server blocks the submission.

The error seems to be related to ModSecurity on the server, as the hosting provider mentioned that some ModSecurity rules are being triggered by the code content, blocking the form submission.

The hosting provider temporarily whitelisted the triggered ModSecurity rule, which resolved the issue, but I am concerned that this issue might occur again in the future. I have a few follow-up questions:

1. Can ModSecurity rules trigger again automatically in the future, causing similar problems with code submissions?
2. Is there any way I can manage or whitelist ModSecurity rules myself to avoid delays in resolving the issue if it happens again?
3. Is there a more permanent solution to allow users to submit forms with code examples without compromising security?
4. Are there recommended server or security settings that would allow safe submission of code (such as JavaScript, PHP, etc.) in forms?

Steps to Resolve:

1. Understand the ModSecurity Rules: ModSecurity protects your site from exploits by blocking specific requests that match its security rules. When you include code in your form, ModSecurity may interpret it as potentially harmful and block it. Temporarily whitelisting a rule solved the issue for you, but this may reoccur since ModSecurity rules can trigger again automatically in the future.

2. Access ModSecurity in cPanel: You can manage ModSecurity settings directly from cPanel to mitigate this issue. Here's how:

   Step 1: Log in to your cPanel.

   Step 2: Scroll down to the Security section and find the ModSecurity icon.

   Step 3: Click on ModSecurity. You will see the current status of ModSecurity for your domain(s).

   Step 4: Disable ModSecurity temporarily for the specific domain where you're facing the issue. This will stop ModSecurity from blocking your form submissions.

   Note: Disabling ModSecurity entirely is not recommended for long-term security, but it may help you test the form and identify if ModSecurity is the exact cause.

3. Whitelist ModSecurity Rules (via Hosting Support): Since you may not have the ability to whitelist ModSecurity rules yourself, you can request your hosting provider (Namecheap in this case) to whitelist specific rules that block your form submissions. This was already done for you once, but you can ask them to:
   • Make the whitelisting permanent, if possible, for the specific forms where code submission is required.
4. Permanent Solutions:
   • Adjust ModSecurity Sensitivity: Ask your hosting provider if they can adjust the sensitivity of ModSecurity for your account. This may allow forms with code content to pass through without triggering a false positive.
   • Use Input Sanitization and Encoding: Ensure that your form content is properly sanitized and encoded before submission. ModSecurity might block content because it interprets certain code as dangerous. By using HTML character encoding or input validation, you can reduce the chance of triggering ModSecurity rules.
   • Content-Type Handling: Another option is to change how your form handles content by using base64 encoding for code inputs, then decoding it on the server-side before processing. This can prevent ModSecurity from identifying the input as executable code.
5. Using Tools like CKEditor: If you're already using a text editor (like CKEditor), you can configure it to treat code snippets as text rather than executable code, which could help prevent ModSecurity from flagging the submission.

Conclusion:

The 403 Forbidden error you're experiencing is primarily due to ModSecurity rules blocking code content in your forms. You can disable ModSecurity temporarily through cPanel for testing, but for a more secure and permanent solution, work with your hosting provider to whitelist specific ModSecurity rules. Additionally, implementing input sanitization, content encoding, and adjusting ModSecurity sensitivity can help in allowing code submissions without compromising security.