Google confirmed today that passwords for its free Gmail online e-mail service had been harvested by hackers, but downplayed the phishing attack as involving just a "small number" of accounts.Earlier Tuesday, the BBC reported that both Gmail and Yahoo Mail had been targeted by a large-scale identity theft scam, perhaps the same one that collected between 10,000 and 20,000 passwords from those services as well as from Microsoft's Windows Live Hotmail, Comcast, Earthlink and others."We recently became aware of a phishing scheme through which hackers gained user credentials for Web-based mail accounts including a small number of Gmail accounts," a Google spokesman confirmed today in a reply to questions from Computerworld . "As soon as we learned of the attack, we forced password resets on the affected accounts. We will continue to force password resets on additional accounts if we become aware of them."Like Microsoft on Monday , Google today denied that Gmail had been hacked, and Gmail usernames and passwords stolen because of a lapse on its end. "This was not a Gmail security issue, but rather a phishing scheme," said the Google spokesman.Google told Gmail users to change their passwords if they suspected that their accounts had been compromised. "If you can no longer sign into your account, you can regain access by answering security questions," the company added, referring to Gmail's single-question automated password reset function .Last year, a Tennessee college student was accused of breaking into former Alaska governor Sarah Palin's Yahoo Mail account by abusing Yahoo's similar reset tool. Shortly after Palin's account was hijacked, Computerworld confirmed that the reset mechanisms used by Hotmail, Yahoo Mail and Google's Gmail could be exploited by anyone who knew an account's username and could answer a single security question .Microsoft, which acknowledged late Monday that passwords for "several thousand" Hotmail accounts had been hijacked by criminals, has blocked access to those accounts, and has made tools available to users who have lost control of their Hotmail inboxes.Neither Google or Microsoft, however, has directly alerted users to the possible danger by sending messages to Gmail or Hotmail accounts, respectively, or by posting a warning on those services.Phishing attacks are on the rise, according to the Anti-Phishing Working Group (APWG), an industry association dedicated to stamping out online identity theft. The APWG's most recent data ( download PDF ), reported that the number of unique phishing-oriented Web sites had surged to nearly 50,000 in June, the largest number since April 2007 and the second-highest total since it started keeping records.