The latest Storm variants...now use a 40-byte key to encrypt their Overnet P2P traffic. This means that each node will only be able to communicate with nodes that use the same key. This effectively allows the Storm author to segment the Storm botnet into smaller networks. This could be a precursor to selling Storm to other spammers, as an end-to-end spam botnet system...we might see a lot more of Storm in the future...
The encryption is trivial and isn't the only new thing found in this variant. It seems to have some new techniques for propagation. Firstly, it is able to scan the file system and drop an executable into any folder with at least one .exe file. Secondly, the worm is able to harvest email addresses from the file system and send spam to those addresses. Lastly, it is able to search for .htm, .html, and .php files and inject malicious IFRAME code into them...
Considering how much this worm has evolved and where it is at currently, I think its time for us to escalate this worm to hurricane category...
Microsoft MVP - Consumer Security 2007-2012
Member of UNITE, Unified Network of Instructors and Trusted Eliminators