Microsoft uncovers new breach while investigating SolarWinds hackers
- An attacker accessed a customer-service agent’s account and used it to try to hack Microsoft customers, the company said
- The White House said the breach is less serious than SolarWinds, calling it ‘unsuccessful, run-of-the-mill espionage’
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.
When Reuters asked about that warning, Microsoft announced the breach publicly.
After commenting on a broader phishing campaign it said had compromised a small number of entities, Microsoft said it had also found the breach of its own agent, who it said had limited powers.
The agent could see billing contact information and what services the customers pay for, among other things.
“The actor used this information in some cases to launch highly-targeted attacks as part of their broader campaign,” Microsoft said.
Microsoft warned affected customers to be careful about communications to their billing contacts and consider changing those usernames and email addresses, as well as barring old usernames from logging in.
Microsoft said it was aware of three entities that had been compromised in the phishing campaign.
It did not immediately clarify whether any had been among those whose data was viewed through the support agent, or if the agent had been tricked by the broader campaign.
Microsoft did not say whether the agent was at a contractor or a direct employee.
A spokesman said the latest breach by the threat actor was not part of Nobelium’s previous successful attack on Microsoft, in which it obtained some source code.
In the SolarWinds attack, the group altered code at that company to access SolarWinds customers, including nine US federal agencies.
At the SolarWinds customers and others, the attackers also took advantage of weaknesses in the way Microsoft programs were configured, according to the Department of Homeland Security.
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Microsoft later said the group had compromised its own employee accounts and taken software instructions governing how Microsoft verifies user identities.
A White House official said the latest intrusion and phishing campaign was far less serious than the SolarWinds fiasco.
“This appears to be largely unsuccessful, run-of-the-mill espionage,” the official said.
Scott McConnell, a spokesman for Homeland Security’s Cybersecurity and Infrastructure Security Agency, said the defensive group “is working with Microsoft and our inter-agency partners to evaluate the impact. We stand ready to assist any affected entities.”
A SolarWinds spokesperson said, “The latest cyberattack reported by Microsoft does not involve our company or our customers in any way.”