Quote: "To defend against concatenated ZIP files, Perception Point suggests that users and organizations use security solutions that support recursive unpacking."

That's the worse advice actually. You want the hidden shit to stay there unable to be seen by default programs. That's how you got all the crap in Windows mail starting from 90's when Outlook started to trying to be "smart" and automatically detect and run additional content. Be dumb and don't discover anything, let it rot in there. The only one that should do this is the antivirus, rest of unpackers/readers/whatever stay dumb.