Microsoft said that the hacker group Lapsus$ gained “limited access” to its systems, following a claim by the group that it obtained source code for the Bing search engine and Cortana voice assistant.

The software giant had been tracking the activities of Lapsus$ — which it labels a “large-scale social engineering and extortion campaign” — for several weeks and provided some details on the methods of its attacks in a blog post late on Tuesday. Lapsus$ had previously breached the cybersecurity defences of Nvidia and Samsung Electronics, and this week also claimed to have gained access to the system privileges of Okta, the San Francisco-based company that manages user authentication services for thousands of corporate clients.

“Our investigation has found a single account had been compromised, granting limited access,” Microsoft said. “Our cybersecurity response teams quickly engaged to remediate the compromised account and prevent further activity. Microsoft does not rely on the secrecy of code as a security measure and viewing source code does not lead to elevation of risk.”

Microsoft does not rely on the secrecy of code as a security measure and viewing source code does not lead to elevation of risk

The hacking group, which has been given the designation DEV-0537 by Microsoft’s cybersecurity researchers, has been expanding the geographic range of its targets and going after government organisations as well as the technology, telecommunications and health-care sectors, according to the blog post. They are also known for hijacking cryptocurrency accounts, Microsoft said.

Lapsus$ has made claims on social media that it’s infiltrated several large tech companies besides Microsoft. Its Telegram channel was first to announce the Microsoft and Okta breaches this week and also included mention of breaching employee accounts of LG Electronics.

“Unlike most activity groups that stay under the radar, DEV-0537 doesn’t seem to cover its tracks,” said Microsoft. “They go as far as announcing their attacks on social media or advertising their intent to buy credentials from employees of target organisations.” — (c) 2022 Bloomberg LP