WASHINGTON (Reuters) -The hacking group behind the SolarWinds compromise was able to break into Microsoft Corp and access some of its source code, Microsoft said on Thursday, something experts said sent a worrying signal about the spies’ ambition.
Source code – the underlying set of instructions that run a piece of software or operating system – is typically among a technology company’s most closely guarded secrets and Microsoft has historically been particularly careful about protecting it.
It is not clear how much or what parts of Microsoft’s source code repositories the hackers were able to access, but the disclosure suggests that the hackers who used software company SolarWinds as a springboard to break into sensitive U.S. government networks also had an interest in discovering the inner workings of Microsoft products as well.
Microsoft had already disclosed that like other firms it found malicious versions of SolarWinds’ software inside its network, but the source code disclosure – made in a blog post – is new. After Reuters reported it was breached two weeks ago, Microsoft said it had not “found any evidence of access to production services.”
Three people briefed on the matter said Microsoft had known for days that the source code had been accessed. A Microsoft spokesman said security employees had been working “around the clock” and that “when there is actionable information to share, they have published and shared it.”
The SolarWinds hack is among the most ambitious cyber operations ever disclosed, compromising at least half-a-dozen federal agencies and potentially thousands of companies and other institutions. U.S. and private sector investigators have spent the holidays combing through logs to try to understand whether their data has been stolen or modified.
