Facebook on Friday said that phone numbers and email addresses belonging to roughly 6 million of its users had been improperly shared due to a software bug in the Facebook platform.
The bug was discovered and reported by a security researcher to Facebook’s White Hat program.
According to a security notice from Facebook, the bug that resulted in unwarranted sharing of user info was connected Facebook’s Download Your Information (DYI) tool.
“If a person went to download an archive of their Facebook account through our Download Your Information (DYI) tool, they may have been provided with additional email addresses or telephone numbers for their contacts or people with whom they have some connection,” Facebook explained in a security note posted late Friday afternoon. “This contact information was provided by other people on Facebook and was not necessarily accurate, but was inadvertently included with the contacts of the person using the DYI tool”
Once the bug was confirmed, Facebook said that the DYI tool was immediately disabled to fix the problem and turned back on the next day, after the flaw was fixed.
No financial or other user information was exposed, Facebook said, adding that there was no evidence the security flaw was exploited maliciously.
“We currently have no evidence that this bug has been exploited maliciously, and we have not received complaints from users or seen anomalous behavior on the tool or site to suggest wrongdoing,” Facebook said.
The security researcher who reported the bug to Facebook’s White Hat program was paid an undisclosed bug bounty for his efforts.
As part of its bug bounty program, Facebook awards a mimuim of $500, and no maximum reward, for each reported bug that is verified by Facebook. Each bug discovered and reported is awarded a bounty based on its severity and creativity.