SAN FRANCISCO, June 25 (Reuters) — Microsoft (MSFT.O) said on Friday an attacker had won access to one of its customer-service agents and then used information from that to launch hacking attempts against customers.

The company said it had found the compromise during its response to hacks by a team it identifies as responsible for earlier major breaches at SolarWinds (SWI.N) and Microsoft.

Microsoft said it had warned the affected customers. A copy of one warning seen by Reuters said the attacker belonged to the group Microsoft calls Nobelium and that it had access during the second half of May.