
The ZIP file typically contains a file that looks like a document (.DOC) but it is really an EXE, there's just a lot of whitespaces between .DOC and .EXE.

Some of these ZIP files are protected by a password which makes it more likely to be allowed through an e-mail server. The password is always in the e-mail message so that the recipient can easily see it.

Using e-mail attachments has made a come back in popularity amongst malware writers during the last few months. We detect this latest batch as variants of the
Worm:W32/Autorun family.