The worm spreads by automatically tweeting a link to a fake Twitter app called "Profile Spy." The link is accompanied by text that reads, "Wow! See who viewed your twitter with Profile Spy" followed by a link.
If a user clicks the link and approves the phony app, two automated tweets are posted to the infected account. The first announces how many people have viewed this particular profile: "53 people viewed my profile today," for example. (HoneyTechBlogreports that this number is likely random). The second tweets a link to Profile Spy.
F-Secure CRO Mikko Hypponen has notified the Twitter community about the worm. "Warning! Do NOT click on Twitter links about 'See who viewed your twitter with Profile Spy', do NOT authorize the 'Profile Spy' Twitter app," he tweeted.
Nevertheless, a Twitter search reveals that the worm is still spreading fast.