The newspaper based its report on people who had attended a recent product demonstration by the Israeli company.
It is not known how many individual cloud accounts may have been targeted by the technique.
An NSO spokesperson said: “We do not provide or market any type of hacking or mass-collection capabilities to any cloud applications, services or infrastructure.”
But the FT noted that NSO did not specifically deny its technology allowed it to deploy the capability described in its product demonstrations.
Google did not comment on the report, while Facebook said it was reviewing the claims.
In separate statements, Amazon, Apple and Microsoft said their security systems were robust.
