Users of LinkedIn are being targeted in a massive spam campaign designed to install the bank credential-stealing Zeus trojan on their machines. The emails, accounting for nearly a quarter of all spam at one point Monday, mimic LinkedIn invitations, according to Cisco. But when users click on the link contained in the message, they are delivered to a website that reads "PLEASE WAITING...4 SECONDS" and then are directed to Google. During that time, however, Zeus is installed on their machines if they are unpatched for certain browser vulnerabilities. This particular spam campaign and ensuing drive-by download attempts are notable because of the size and the apparent targets: business professionals with access to corporate bank accounts, Henry Stern, a Cisco senior security researcher, said in a blog post. — DK