There has been a lot of talk as of late about hosting companies discontinuing service to Joomla 1.5.26 website customers. The primary reason pertains to a security exploit that is widely known to allow unauthorized file uploads to a Joomla 1.5.x website installation. If an attacker - human or bot - is able to upload a file to your hosting account then you pretty much lost almost all of your defenses. Through a single uploaded file, if properly coded - the attack would be able to copy, export, delete or modify any or all elements of your files, images, databases, emails, etc. It essentially opens your hosting account and your website to any attack the infiltrator would like to carry out, ranging from defacing your website to sending massive amounts of spam to setting up a phishing website or distributing malware.