A security vulnerability in Gmail may allow attackers to set up filters on users' email accounts without their knowledge, according to a proof-of-concept exploit posted on the Geek Condition website on Sunday.
The post states that the vulnerability has caused some people to lose their domain names registered through GoDaddy.com.
The post explains that the exploit relies on obtaining the variables that represent the username and 'at': "When you create a filter in your Gmail account, a request is sent to Google's servers to be processed. The request is made in the form of a url with many variables. For security reasons, your browser doesn't display all the variables contained within the url. Using Firefox and a plug-in called 'Live HTTP Headers', you can see exactly what variables are sent from your browser to Google's servers."
After that, an attacker just needs to identify the variable that is the equivalent of the username.
"Obtaining this variable is tricky but possible," the post states. "I'm not going to tell you how to do it; if you search hard enough online, you'll find out how."
The 'at' variable can be obtained by visiting a malicious website, the post states, suggesting that Google makes the 'at' variable expire after every request rather than after every session.
To avoid falling victim to the vulnerability, users should check their filters often, the post suggests. Firefox users can download an extension called 'NoScript' that helps prevent these attacks.
Any website that uses cookies for authentication requests can be taken advantage of in the same way. To avoid becoming a victim of this type of exploit, Gmail users should log out of their accounts when they are not in use, and not visit websites that they don't trust.
Google representatives did not immediately return a request for comment.
