The attacks were part of a Chinese campaign known as Cloudhopper, which the United States and Britain said infected technology service providers to steal secrets from their clients. While cybersecurity firms and government agencies have issued multiple warnings about the Cloudhopper threat since 2017, they have not disclosed the identity of technology companies whose networks were compromised.

However, the comments appear to have confused the alledged victims of the attack. IBM said it had no evidence that sensitive corporate data had been compromised. HPE said it could not comment on the Cloudhopper campaign.

Cloudhopper targeted managed service providers (MSPs) to access client networks and steal corporate secrets from companies around the globe, according to a US federal indictment of two Chinese nationals unsealed on Thursday.

Prosecutors did not identify any of the MSPs that were breached. Cloudhopper, which has been targeting technology services providers for several years, infiltrated the networks of HPE and IBM multiple times in breaches that lasted for weeks and months. Reuters was unable to confirm the names of other breached technology firms or identify any affected clients.

IBM and HPE provided statements but declined to comment on the specific claims made by the sources. "The security of HPE customer data is our top priority," HPE said. "We are unable to comment on the specific details described in the indictment, but HPE's managed services provider business moved to DXC Technology in connection with HPE's divestiture of its Enterprise Services business in 2017."

"IBM has taken extensive counter measures worldwide as part of its continuous efforts to protect itself and its clients against constantly evolving threats", the company said in an emailed statement. "We take responsible stewardship of client data very seriously and have no evidence that sensitive IBM or client data has been compromised."