Tool created to aid cleanup from Microsoft hack in broad use

The breach was discovered in early January and was attributed to Chinese cyber spies targeting U.S. policy think tanks. Then in late February, five days before Microsoft Corp. issued a patch on March 2, there was an explosion of infiltrations by other intruders, piggybacking on the initial breach.

The White House earlier this month described the hack as an “active threat” that was being addressed by senior national security officials. The administration’s response is being led by deputy national security adviser Anne Neuberger, who convened government officials and private sector experts to brainstorm solutions, particularly given that smaller businesses often lack resources to counter cyberattacks and to clean up after hacks.

Since the release of the tool, the number of vulnerable systems has fallen to fewer than 10,000 from at least 120,000 at the peak.

While Microsoft has taken considerable heat for being the provider of software that elite hackers have exploited, Charles Carmakal, senior vice president and chief technical officer of prominent cybersecurity firm FireEye, said Microsoft, based in Redmond, Wash., deserves credit for working hard to help people who run its software defend themselves.

He cited, especially, the downloadable turnkey script that people can use to apply patches and see if their systems have been compromised.

“The level of effort that they put into this to help companies defend themselves is terrific,” he said. “It’s a tough situation that organizations are in with the vulnerability in general.”