On December 13, dozens of organizations across the United States, Canada, Australia, and New Zealand received email messages demanding $20,000 in bitcoin in return for the location of bombs  that had allegedly been planted at their offices. While the threats caused some confusion and a fair amount of annoyance, no bombs were found anywhere the threat was received.

While there is now an international search for the perpetrator(s), researchers at Talos say that the actors behind the bomb threats seem to be the same groups behind the waves of "sextortion" and blackmail email messages that have been plaguing victims since early summer.

"What they're doing now is kind of refining their social engineering approach to try to come up with other situations where the victim might actually be convinced to send the bitcoins," says Jaeson Schultz, technical leader at Talos. He points out that some of the specific language in the email messages, the address range of the senders, and the bitcoin wallets provided as the destination of the ransom all point to the same group of actors behind the evolving attacks.

And the attacks are evolving ever more rapidly. By late yesterday afternoon, the bomb threats had ceased, to be replaced with personal threats; acid attacks were the weapon of choice in the later extortion attempts.

Those personal threats are a return to an older tactic, says Schultz. "We've seen examples of messages where, for example, the attackers were claiming that they were a hit man who was hired to chop off the victim's hands or something. They had a change of heart, and now they are willing to — for a price that's paid in bitcoin — call off the attack and provide information about who hired them," he explains, saying that these rather gruesome messages were more common in September but had slowed.

Schultz says that researchers have been monitoring the bitcoin wallets provided as a target for the ransom, and that it doesn't appear as though any of the victims had actually paid the ransom. Colin Bastable, CEO of Lucy Security doesn't think that collecting ransom was really part of the attackers' plans. "This isn’t about extortion, it is about causing disruption. It worked," he said in a statement provided to Dark Reading. He continued, "There was no feasible way to collect money – so whilst it was criminal, the cost was paid in mass disruption. I think it is a trial run to see how America responds in such cases."

Schultz agrees with Bastable's broad conclusion about the ransom. "I guess the only thing I can kind of deduce is that the criminals in this case are not necessarily worried about having bitcoins that are tainted through this malicious activity." And he doesn't think we've seen the last of these attacks.

"Evidently these folks are making enough money that it is worth their time to continue these these tactics and I think it speaks to the fact that social engineering is one of the more powerful attacks out there," Schultz says. "It's an attack on the users themselves who are oftentimes the weakest link in any sort of a secure system."

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