Original URL: http://www.theregister.co.uk/2007/07/03/mpack_reloaded/
MPack malware exposes cheapskate web hosts
Apache and the Domino Effect
Poor configuration of Apache servers allowed multiple websites hosted on the same physical server to become infected in last month's Mpack compromise.
An analysis  by security researchers at the SANS Institute's Internet Storm Centre reveals that only one of the websites hosted on a machine needed to contain a vulnerable PHP script to infect all the sites hosted on systems, in cases where Apache permissions were improperly configured. Often the root cause of the problem is when hosting firms skimp on hardware needed to add an extra layer of protective virtualisation.
Thousands of websites (mainly in Italy) were recently compromised using the MPack malware kit. This contained iframe tags that pointed surfers towards hacker-controlled websites.
"The main reason why this attack was possible was the fact that Apache’s process must be able to read all files (in order to serve/process them) and that the file system permissions were not correctly set. It remains questionable how many big hosting sites are affected with this (poor) setup," SANS Institute researchers conclude. "Check if your hosting company uses chroot and/or suExec because that is the only way to make sure that your own web site will not be compromised by other users sharing the same physical server."
MPack is a malware kit, sold online to hackers at prices ranging from $500 to $1,000. The application is offered with modular extras, maintenance updates and what amounts to support contracts that in many ways rival or surpass those offered by legitimate software suppliers. ®