Botnet disruption shows aggressive U.S. cyber posture

What's happening: The military's Cyber Command recently disrupted the TrickBot botnet, per the Washington Post and CyberScoop News.

• U.S. officials were concerned the botnet, which has generally been used in ransomware schemes, would be deployed to snarl up computer systems tied to U.S. elections.
• Cyber Command reportedly doesn't expect the move to permanently take the network offline, but it hopes its action will be enough to degrade the TrickBot-linked syndicate's capabilities until after the election.

The big picture: In general, the Trump administration has been willing to launch much more aggressive cyber operations than its predecessor, including on botnet takedowns, says a former senior intelligence official.

• The Obama administration discussed stripping botnet-planted malware out of victims' computers, recalls this official, in an operation that could have also swept up U.S.-based devices.
• But the operation never happened because officials believed if it went awry, the U.S. government would be deemed responsible for covertly damaging infected computers.
• "The chance of a negative incident was so small, so small — minute," recalls the official. "But it was enough for them to not do it."

This changed with the Trump administration, whose "risk tolerance is higher," this person says. "They’re willing to take the risk of upsetting other countries."

The intrigue: The blow to TrickBot reflects that growing assertiveness, which has emerged under cyber commander Paul Nakasone and his doctrine of "persistent engagement" — the idea that U.S. cyber spies should deal blows against adversaries instead of merely playing defense.

The catch: As experts have noted, Cyber Command’s actions raise serious questions about the scope of its powers.

• The Pentagon’s cyber operators have targeted malicious nation-state actors and even terrorists like ISIS, but this is the first documented case of them executing an operation against a cyber criminal group.
• It's unclear what authority the U.S. military has to do so, particularly absent a demonstrable contemporary connection between the TrickBot syndicate and the Russian government, or any other state actor.

Privacy concerns have also been raised.

• In addition to padding the TrickBot network’s records with fake data, Cyber Command’s operation involved pushing out a phony update to infected computers, including in the U.S., cutting them off from the cyber criminals' control.

• That means Cyber Command forcibly altered the functioning of U.S.-based computers, unbeknownst to their users.
• Of course, this was done for benign reasons. But it still leaves open the question of whether the government, by forcing its way into Americans' computers, violated the Fourth Amendment.

Meanwhile: Private actors are also moving against the group behind TrickBot.

• In a related action, Microsoft, leading a coalition of private cybersecurity firms, got the go-ahead from a U.S. federal court to start disabling the syndicate's access to servers critical to TrickBot infrastructure, the company announced Monday.
• Yes, but: Like Cyber Command, the Microsoft-led coalition believes its action won't keep the cybercriminals from eventually rebuilding TrickBot.

Context: There are more than 1 million computers and other Internet of Things devices hijacked by the TrickBot network, which has been active since 2016.

• In September, TrickBot operators used the network to launch a major ransomware attack against United Healthcare Services, a large U.S.- and U.K.-based health care company.

The bottom line: The Cyber Command and Microsoft-led actions should forestall similar attacks, at least for a little while. The broader debates around appropriate cyber policy will long outlive TrickBot’s period of darkness.