A huge flaw in Google’s wildly popular Gmail service was recently discovered that may have exposed the email addresses of every single user. According to a report from Wired, security researcher Oren Hafif found and helped Google fix a serious bug that left Gmail users’ email addresses exposed to anyone with a bit of patience. While digging up addresses would have taken quite a bit of time, the report notes that the bug had existed for years before it was fixed, and it easily could have been utilized to obtain every Gmail user’s address.

According to the report, the bug would not have exposed any passwords or other sensitive data.

“The exploit involved a lesser-known account-sharing feature of Gmail that allows a user to ‘delegate’ access to their account,” Wired’s Andy Greenberg wrote. “In November of last year, Hafif found that he could tweak the URL of a webpage that appears when a user is declined that delegated access to another user’s account. When he changed one character in that URL, the page showed him that he’d been declined access to a different address. By automating the character changes with a piece of software called DirBuster, he was able to collect 37,000 Gmail addresses in about two hours.”

Using the flaw, Hafif says he could have obtained the email addresses of every single Gmail user in the world in a matter of days or weeks.

Zach Epstein has worked in and around ICT for more than 15 years, first in marketing and business development with two private telcos, then as a writer and editor covering business news, consumer electronics and telecommunications. Zach’s work has been quoted by countless top news publications in the US and around the world. He was also recently named one of the world's top-10 “power mobile influencers” by Forbes, as well as one of Inc. Magazine's top-30 Internet of Things experts.