Groupon subsidiary Sosasta.com accidentally published a database containing the email addresses and clear-text passwords of 300,000 users and the cache was indexed by Google.

The trove of personal data was discovered by Australian security consultant Daniel Grzelak as he plugged a handful of query terms into the search engine, he said Tuesday. He contacted Patrick Gray with security blog Risky Biz, which reported that the SQL database contained the details for 300,000 Sosasta account holders.

A Groupon spokesman confirmed that the digital coupon distributor “was alerted to a security issue” on Thursday night and corrected the problem immediately. The issue was limited to Sosasta, which uses its own servers and network and isn't connected to Groupon's systems in other countries.

“We have begun notifying our subscribers and advising them to change their Sosasta passwords as soon as possible,” the spokesman said in a statement. “We will keep our Indian subscribers fully informed as we learn more.”

At time of writing, there was no advisory on either the Groupon or Sosasta websites, although Sosasta's Facebook page contained a notice that came in the form of a JPG image that couldn't easily be indexed by Google or other search engines. Ah the irony.

According to Risky Biz, Grzelak found the massive cache as he was looking for additions to shouldichangemypassword.com, a side project that indexes email addresses included in more than a dozen high-profile privacy breaches carried out by LulzSec and other hacking groups. The query that hit pay dirt included the terms “filetype:sql” “password” and “gmail.”

“I started scrolling, and scrolling and I couldn't get to the bottom of the file,” Grzelak told Risky Biz. “Then I realised how big it actually was.”

The Groupon statement didn't say why passwords weren't encrypted or why such a sensitive file was publicly available.

The snafu is the latest to expose the folly of using the same password on more than one site, a practice still followed by a shockingly high number of people. If you're one of them, you ought to consider using a password-management program such as Password Safe or KeePass.

The Groupon subsidiary sure isn't the first to carelessly expose data it has promised to keep private, and judging from this Google search, it's probably not the last. ®