The creator of the photo-sharing app Snapchat has confirmed that a known security flaw was responsible for a hacking that saw more than 4.6 million users' names and phone numbers posted online.
Snapchat received warnings about the flaw in the app's Find Friends service months ago but played down the threat and ignored fresh warnings from a security firm days before the app was spectacularly breached on New Year's Eve.
Evan Spiegel, the app's 23-year-old CEO and co-founder, confirmed to NBC Today the Find Friends function had been "abused" and said he was "outraged" over the hacking.
"At the time we thought we had done enough," he said. "But I think in a business like this ... that is moving so quickly if you spend your time looking backwards you're just going to kill yourself."
Snapchat has since released an updated version of the app which it believes will thwart future hacking attempts.
More than 4.6 million Snapchat accounts have reportedly been affected after hackers downloaded the usernames and phone numbers of users and temporarily posted them online.
A site called SnapchatDB.info, which has since been taken offline, published the usernames and phone numbers for 4.6 million accounts online and made the information available to download.
The hackers, who censored the last two digits of users' phone numbers, said their goal was to raise awareness about Snapchat's security flaws in a statement to Techcrunch:
"Our motivation behind the release was to raise the public awareness around the issue, and also put public pressure on Snapchat to get this exploit fixed.
"It is understandable that tech startups have limited resources but security and privacy should not be a secondary goal. Security matters as much as user experience does."
Snapchat, which allows users to share pictures which automatically delete themselves after being viewed, did not immediately respond to an email request for comment from ITV News.
The founder of increasingly popular photo-sharing app Snapchat has turned down a $3bn (£1.87bn) takeover offer from Facebook, according to a report in the Wall Street Journal.
The smartphone app, co-founded by American Evan Spiegel for a project at Stanford University, allows millions of users - predominantly teenagers - to share photographs which destroy themselves after a few seconds.
Spiegel is hoping that Snapchat, which currently has no charges or advertisements, will be valued at more than $4bn when he considers acquisition offers next year, the report said.
Facebook bought image-sharing rival Instagram for $1bn in 2012.