We’ve entered a new era in Mac security, but there’s no need to panic.

. . . Flashback is the name for a malicious software program discovered in September 2011 that tried to trick users into installing it by masquerading as an installer for Adobe Flash. (Antivirus vendor Integobelieves Flashback was created by the same people behind the MacDefender attack that hit last year.) While the original version of Flashback and its initial variants relied on users to install them, this new form is what’s called in the security business a drive-by download: Rather than needing a user to install it, Flashback uses an unpatched Java vulnerability to install itself.