The FBI and law enforcement officials in more than a dozen countries have made scores of arrests in cases involving Blackshades, malicious software that allows users to surreptitiously peep into the computers and web cameras of others. In what the FBI said was the largest global cyber operation to date, raids were carried out in 18 countries at the homes of people suspected of buying the malware, which was available for a $40 download. The targets for law enforcement included the creators and administrators of Blackshades. The software was used last year against Miss Teen USA Cassidy Wolf in what...