Google on Tuesday reported that it has investigated recent reports of a Gmail vulnerability and found the flaw: users duped by phishing messages.

Google security engineer Chris Evans in a blog post explained that in response to speculation about an alleged security vulnerability in Gmail, Google has looked into the matter and found no evidence of a Gmail vulnerability.

On Sunday, in a post on the GeekCondition.com blog, Web developer Brandon Partridge warned that an attacker can force an unsuspecting Gmail user to create a malicious message filter without his or her knowledge.

This would enable an attacker to hijack messages sent to the victim without the victim's knowledge.

But the vulnerability turns out to be gullible users who fall for a phishing scam.

"Attackers sent customized e-mails encouraging Web domain owners to visit fraudulent Web sites such as 'google-hosts.com' that they set up purely to harvest usernames and passwords," explained Evans. "These fake sites had no affiliation with Google, and the ones we've seen are now offline. Once attackers gained the user credentials, they were free to modify the affected accounts as they desired. In this case, the attacker set up mail filters specifically designed to forward messages from Web domain providers."

Security researcher Petko D. Petkov of GNUCitizen.org, who identified a Gmail vulnerability last year, said the technique described by Partridge appeared to be some form of cross-site scripting (XSS), rather than the cross-site request forgery vulnerability he had found. Though his assessment may be misplaced in this instance, it would be unwise to believe that no further Gmail holes will be identified.

Evans recommends that Google users only enter Gmail sign-in credentials to Web addresses starting with https://www.google.com/accounts and that they "never click-through any warnings your browser may raise about certificates."

It might also be worth adding that one should be skeptical about the legitimacy of e-mail messages, particularly from unknown sources.