Composer & PHP cURL SSL Errors caused by Norton 360 (Network / SSL Inspection)

Norton 360 for Windows
1

Hello community and Norton support team,

I am writing this post to share an issue I recently experienced with Norton 360 on Windows 11 and how it severely impacts local PHP development tools, specifically Composer and PHP cURL.

The Problem

While using XAMPP (PHP 8.2.12) and running CLI tools like composer diagnose or updating packages via Composer, cURL requests to packagist.org and GitHub consistently failed with network connectivity and SSL/TLS timeout errors.

When checking the status via command line (composer diagnose), Composer flagged potential firewall/antivirus blocking.

What Was Tested

  1. Executed standard Composer and cURL network checks.

  2. Verified local PHP OpenSSL extensions and configurations (all enabled properly).

  3. Temporary rule tweaks on standard Windows settings did not yield results.

The Resolution

After trying multiple troubleshooting steps without success, I completely uninstalled Norton 360.

Immediately after rebooting the machine without Norton 360, I re-ran composer diagnose and the output was 100% OK:

  • Checking http connectivity to packagist: OK

  • Checking https connectivity to packagist: OK

  • Checking github.com rate limit: OK

Question / Suggestion

It appears that Norton 360’s deep packet inspection (SSL/TLS inspection or Smart Firewall) silently blocks or corrupts HTTPS traffic generated by PHP’s CLI binary (php.exe) and cURL requests.

  1. Is there a recommended configuration or official rule set for developers using PHP/Composer alongside Norton 360 without having to completely disable SSL inspection or Smart Firewall?

  2. Can the team look into improving default whitelist handling for developer tools like php.exe in local environments (C:\xampp\php\php.exe)?

Hopefully, this post helps other developers encountering similar cURL/Composer connection failures! I ditched Norton 360 because it prevents Composer from using SSL/TLS, and—as I likely mentioned above—the issue was only resolved once I completely uninstalled Norton from the computer. With Windows Defender, everything is running perfectly.Thanks a lot.