Back in 2015, Israeli intelligence officials hacked into Kaspersky systems and discovered the presence of an improvised search tool used to search computers worldwide for mentions of code names of American intelligence programmes, according to The New York Times.
The Russian government has used popular antivirus software for the search of secret documents around the world.
While the case of spies spying on spies has only come to light now, the Israeli intelligence officials revealed their findings to the U.S. which moved to ban the use of Kaspersky software on U.S. government computers.
It is not yet publicly known what other US secrets the Russian hackers may have discovered by turning the Kaspersky software into a sort of Google search for sensitive information, the Times said. It was founded in 1997 by Eugene Kaspersky, who is now the CEO.
"Israeli spies had found the hacking material on the network of Kaspersky Lab, the global anti-virus firm under a spotlight in the United States because of suspicions that its products facilitate Russian espionage". "There is no way, based on what the software was doing, that Kaspersky couldn't have known about this", an official said.
The current and former government officials who described the episode spoke about it on condition of anonymity because of classification rules, the Times said.
"According to the spokesperson, the company has not received any evidence of the allegations".
The extensive system-wide permissions that antivirus software necessitates and the trust it demands of its users make Kaspersky's products an ideal target for governments wishing to spy on their adversaries.
Germany's BSI, which also uses Kaspersky products for technical analyses, said it was in touch with US officials and other security agencies about the issue so it could take action and issue a warning on short notice if required.
Eugene Kaspersky, the company's co-founder and chief executive, has repeatedly denied charges his company conducts espionage on behalf of the Russian government.
US intelligence agencies have concluded that Russian President Vladimir Putin ordered a multipronged digital influence operation a year ago in an attempt to help Donald Trump win the White House, a charge Moscow denies.