LONDON • The United States has opened a new line of combat against Islamic State in Iraq and Syria (ISIS), directing the military's six-year-old Cyber Command for the first time to mount computer network attacks that are now being used alongside more traditional weapons.
The effort reflects US President Barack Obama's desire to bring many of the secret US cyber weapons that had been aimed elsewhere, notably at Iran, into the fight against ISIS - which has proved effective in using modern communications and encryption to recruit and carry out operations.
The National Security Agency (NSA), which specialises in electronic surveillance, has for years listened intensely to ISIS militants.
But the NSA's military counterpart, Cyber Command, was focused largely on Russia, China, Iran and North Korea - where cyber attacks on the US most frequently originate - and had run virtually no operations against what has become the most dangerous terrorist organisation in the world.
A review of what should be done to confront ISIS was on Mr Obama's agenda yesterday at a conference in Germany, with the leaders of Britain, France, Italy and Germany.
Of these efforts, the cyber campaign is the newest. It is also the one discussed in least detail and its successes or failures are the most difficult to assess from the outside.
We are dropping cyberbombs.
UNITED STATES DEPUTY SECRETARY OF DEFENCE ROBERT WORK
But officials said a decision was made that a bit of boasting might degrade the enemy's trust in its communications - jumbling and even deterring some actions.
The goal is to disrupt the ability of ISIS to spread its message, attract new adherents, circulate orders from commanders and carry out day-to-day functions, like paying its fighters.
A benefit of the administration's exceedingly rare public discussion of the campaign, officials said, is to rattle ISIS commanders, who have begun to realise that sophisticated hacking efforts are manipulating their data. Potential recruits might also be deterred if they come to worry about the security of their communications.
"We are dropping cyberbombs," US deputy secretary of defence Robert Work said. "We have never done that before."
Officials indicate that the effort has begun with a series of "implants" in ISIS networks to learn the online habits of commanders. Now, the plan is to imitate them or to alter their messages, with the aim of redirecting militants to areas more vulnerable to attack by US drones or local ground forces.
In other cases, officials said, the US may complement operations to bomb warehouses full of cash by using cyber attacks to interrupt electronic transfers and misdirect payments.
Mr Obama's national security adviser Susan Rice has said the fight against ISIS had to be thought of as a multifront war, with computers just another weapon in the arsenal.
"It should not be taken out of proportion - it is not the only tool," she said when asked about Mr Work's "cyberbombs" comment.
In fact, some of Mr Work's colleagues acknowledged that they had winced when he used the term because government lawyers have gone to extraordinary lengths to narrowly limit cyber attacks to highly precise operations with as little collateral damage as possible.
But Ms Rice said ISIS had "uniquely utilised cyberspace" to recruit, to communicate over encrypted apps and to coordinate operations .
NSA officials complained that once the implants were used to attack, ISIS would stop the use of a communications channel and perhaps start one that was harder to find, penetrate or decrypt.
"It's a delicate balance," Ms Rice said. "We still have to keep our eye on the Russia-China state-sponsored activity, but this is a new mission, one where we have to balance the collection equities against the disruption equities."
NEW YORK TIMES