A hacker called Shiny Hunters claims to have stolen over 500GB of source code and other confidential data from Microsoft’s private GitHub repositories. According to Bleeping Computer, the hacker got access to the data after breaking into the GitHub account of a Microsoft employee. The account is since believed to have been secured and the hacker apparently no longer has access to it.

The breach is believed to have happened in late March, but only came to light on Thursday after the alleged perpetrator started contacting media outlets with evidence about the hack. According to the report, the hacker initially planned to sell the private source codes on the Dark Web, but eventually changed his mind and is looking to give it away for free.

While some fellow hackers on the dark web initially refused to believe that the leaked data was authentic because of references to latelee.org and the presence of Chinese text, multiple Microsoft sources have since confirmed to ZDNet that the data, indeed, is for real and that the account in question was breached by at least one or more unauthorized individuals.

Thankfully for the Redmond giant, most of the leaked data are code samples, test projects, an eBook and other generic items, which means the hacker did not get access to the source code of any major Microsoft core projects, such as Windows and Office. Either way, Microsoft is yet to officially confirm the hack, so it will be interesting to see if the company will offer any further insight into the developments.