I followed up with MT and below is their response. Totally makes sense and I’ll be taking their described steps to harden my sites. Here’s the main link they provided below:
GS:Improve your PHP security
https://wiki.mediatemple.net/w/GS:Improve_your_PHP_security
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As a courtesy, I ran a scan on your (gs) Grid-Service to find and remove any known malware and payloads that our customers have been infected with recently. The results of this scan can be found in the mt_change.log file located in your home directory, as well as the changelog file located in data/mt_dbclean.
I definitely do see that the infection has spread across several domains as you’ve reported. However, this is most likely due to the infection gaining access to your (gs) Grid-Service through an out-of-date WordPress installation. Unless you enable open_basedir restrictions to secure PHP on your (gs) Grid-Service a bit further, it will be possible for these infections to spread across all domains. This is why you saw the infection on static HTML sites. That being said, enabling open_basedir restrictions would provide you with added security. This would essentially isolate your domains from each other, which would prevent the infection from spreading.
GS:Improve your PHP security
https://wiki.mediatemple.net/w/GS:Improve_your_PHP_security
The out-of-date WordPress installation that I’m seeing is for the domain xxxxxxx.com. You will want to update this, as well as other CMS installations that you have on your (gs) Grid-Service, to the latest version. Currently, the latest version of WordPress is 3.0.3. The latest releases, according to WordPress/Codex, are mandatory updates. This is due to the nature of the update, which was done as a security patch for exploits that were made known.
Please do keep in mind that we are happy to help you set up everything regarding our servers, and will often go the extra mile to help you set up third-party software to access our servers correctly; however, we are not responsible for the configuration or malfunctions of third-party software.
You may also consult the “Scope of Support” page for more details regarding the scope and amount of support covered by (mt) Media Temple for this and/or other specific products. Please visit the following URL for more information: https://www.mediatemple.net/go/sos/.
Let me know if there’s anything else I can answer for you regarding your (mt) Media Temple services.
Best regards,