Anti Virus software is pretty much entirely worthless for protecting from this sort of attack. Anti Virus software is largely botnet size limiting software. It is to prevent a botnet virus from spreading to two million machines, not to prevent it from spreading to one million machines and definitely not to prevent it from infecting *you*. In other words, anti virus software is for protecting you decently from old viruses, and to protect from new viruses before the entire set of vulnerable machines become infected. It is not meant to stop a hacker from infecting you, and it fails horribly at doing this.