Group Behind Alleged Russia Hack Broke Into Microsoft's Internal Systems

The group behind the suspected Russian attack into U.S. government agencies and private companies was able to hack into Microsoft's internal systems and access some of the company's source code, the tech giant said in a blog post on Thursday.

Microsoft had previously said it was among thousands of companies that discovered malware on its systems after downloading a routine software update from the IT company SolarWinds containing a possible "backdoor" for hackers to gain access to sensitive company data.

But the admission Thursday is the first time Microsoft acknowledged the attackers did more than place a tainted software update on its system: hackers successfully broke into the company's systems and viewed source code, the carefully guarded DNA of the company's software products.

Microsoft said after first believing it had blocked the intrusion, some "unusual activity" on a "small number" of employee accounts tripped an alarm. When the company homed in, a startling finding appeared: company source code "in a number of source code repositories" had been accessed by hackers.