I was recently preparing a new installation of Magento CE version 126.96.36.199 via SSH, but after using wget to pull down the file system and going through the standard permissions settings as described in the Magento wiki article, I could not access the browser-based installation process. All I could get was a 403 permission error. It didn’t take much Googling around to discover that this issue is not unique to me. Maybe it’s due to something happening in transmission/extraction or maybe there is something wrong in the file system to begin with; either way the permissions settings are not correct somewhere in the file system.
Thankfully, it’s an easy fix via SSH. Make sure you’re in the root directory of your Magento installation, and then execute the following commands:
find ./ -type f | xargs chmod 644 find ./ -type d | xargs chmod 755chmod -Rf 777 var chmod -Rf 777 media
Clear your browser cache and reload the URL of your Magento instance. At this point you should be able to continue with the browser-based installation process and begin setting up your store.