The New York Times details how Israeli intelligence officers hacked into the Kaspersky Lab network in 2014 and spent months watching Russian government hackers use the company's antivirus software to look for U.S. classified government programs:
The Russian operation, described by multiple people who have been briefed on the matter, is known to have stolen classified documents from a National Security Agency employee who had improperly stored them on his home computer, on which Kaspersky’s antivirus software was installed. What additional American secrets the Russian hackers may have gleaned from multiple agencies, by turning the Kaspersky software into a sort of Google search for sensitive information, is not yet publicly known.
Earlier this month, ABC News reported on the NSA contractor's home computer breach but did not reveal Israel's role in notifying U.S. officials. The NSA, already aware that antivirus software can allow dangerous access, prohibited employee use of Kaspersky software, but the Department of Homeland Security did not ban Kaspersky software on all government computers on September 13, 2017.
Kaspersky Lab continues to deny any knowledge of or involvement in government hacking activities using its products:
Technical experts say that at least in theory, Russian intelligence hackers could have exploited Kaspersky’s worldwide deployment of software and sensors without the company’s cooperation or knowledge. Another possibility is that Russian intelligence officers might have infiltrated the company without the knowledge of its executives.
But experts on Russia say that under President Vladimir V. Putin, a former K.G.B. officer, businesses asked for assistance by Russian spy agencies may feel they have no choice but to give it. To refuse might well invite hostile action from the government against the business or its leaders. Mr. Kaspersky, who attended an intelligence institute and served in Russia’s Ministry of Defense, would have few illusions about the cost of refusing a Kremlin request.
How Israel Caught Russian Hackers Scouring the World for U.S. Secrets (NYT)