Just a quick note and apology to users of the DSTK EC2 AMI. The default public key that Amazon adds to ~/.ssh/authorized_keys wasn't being removed automatically during the AMI creation process as I expected, so I had unknowingly been given login access to any unmodified instances created from a DSTK AMI. Happily Amazon's audit procedures spotted the problem, so I've now gone ahead and built a new version with my public key removed. Apologies to everyone, that was my mistake. To be clear the worst case was that I would be able to log in to a server you'd created, it didn't give anyone else access.
I've updated the docs and released ami-a971b7c0 as the current version of DSTK 0.35. I recommend users of the current AMI either switch to the new one, or just edit ~/.ssh/authorized_keys to remove the first line containing my key. It will be the line that begins ssh-rsa AAAAB3Nza… Be careful not to delete your own login credentials, or you'll be unable to log into the box yourself!
To be sure I wasn't missing anything else I've been studying the Amazon guide to creating shared AMIs, and use the following commands just before I build the image to wipe sensitive data like website visitors, command line histories and the default server SSH keys:
sudo rm -rf /var/log/apache2/*
sudo rm -rf ~/.ssh/authorized_keys
sudo rm -rf /etc/ssh/ssh_host_dsa_key
sudo rm -rf /etc/ssh/ssh_host_dsa_key.pub
sudo rm -rf /etc/ssh/ssh_host_rsa_key
sudo rm -rf /etc/ssh/ssh_host_rsa_key.pub