Microsoft encountered a rare error earlier this month when department staff IT of the company accidentally left one of Bing's backend servers exposed on the internet.
The server was discovered by Ata Hakcil, a security researcher at WizCase, who shared his findings exclusively with ZDNet last week.
According to Hakcil's research, the server is believed to have exposed more than 6,5 TB records containing 13 billion archives coming from the Bing search engine.
Hakcil said the server was exposed online from September 10 to September 16, which alerted the Microsoft Security Response Center (MSRC), and that the post server was secured with a password.
Last week, Microsoft admitted its mistake.
"We've fixed a configuration that caused a small amount of search query data to be reported," a Microsoft spokesman said last week.
"After the analysis, we found that the exposed data was limited and undefined."
ZDNet, which was given access to the server while exposed to the Internet without password, can confirm that no personal user information has been exposed.
Instead, the server reported technical details, such as search queries, user system details (device, operating system, Browser etc.), geographical location details (where available) and various Tokens, hashes, and coupon codes.
Over the past four years, Elasticsearch servers have often been the source of many random data leaks.