The details were posted on bitcoin forum btcsec.com by a user named Tvskit. The user said that approximately 60 percent of the passwords are still active but Google refuted the claim and said that only 2 percent of the passwords still work and also said that its automated anti-hijacking systems would have blocked many of the login attempts.

A Google spokesman told Mashable that the company has "no evidence that our systems have been compromised," and security experts seem to agree that the passwords are either old Gmail passwords obtained through phishing, or are passwords that were actually used on other sites.

Find out if your Gmail account has been hacked 

With increased snooping and rising privacy concerns, it has now become more important to keep your personal data away from external interference. But the Internet giant has come up with tools that will enable you to keep a track of Gmail account.

To make this feature more accessible to users, these tools have been made available within the Gmail inbox.

All you need to do is just scroll down to the bottom of your inbox and locate a link called ‘Details’. A pop-up window will appear after you click the link. This pop-up window will show you a detailed list of your account activity, i.e. the last ten times anyone or you else have accessed your account. The list will show how your account was viewed, i.e. email app, browser, IP address and location of the person and also the time of access.

Gmail, which includes calendar and chat features, has gained popularity over the past decade to become one of Google's most successful product offerings.

With more than 420 million users, it has begun to make small inroads against Microsoft Exchange in the battle to provide email services for corporate customers as well as individual consumers.

Researchers hack into Gmail with 92 percent accuracy

A team of US engineers has developed a method that allows them to successfully hack into apps including Gmail up to 92 percent of the time.

They have identified a weakness believed to exist in Android, Windows and iOS mobile operating systems that could be used to obtain personal information from unsuspecting users. Researchers tested the method and found it was successful between 82 percent and 92 percent of the time on six of the seven popular apps they tested.

Among the apps they easily hacked were Gmail, CHASE Bank and H& R Block. Amazon, with a 48 percent success rate, was the only app they tested that was difficult to penetrate.

Once a user downloads a bunch of apps to his or her smart phone they are all running on the same shared infrastructure, or operating system. ‘The assumption has always been that apps cannot interfere with each other easily. We show that assumption is not correct and one app can in fact significantly impact another and result in harmful consequences for the user,’ explained Zhiyun Qian, an assistant professor at University of California's Riverside Bourns College of Engineering. 

The attack works by getting a user to download a seemingly benign, but actually malicious app, such as one for background wallpaper on a phone.

Once that app is installed, researchers were able to exploit a newly discovered public side channel - the shared memory statistics of a process, which can be accessed without any privileges. Shared memory is a common operating system feature to efficiently allow processes share data.

Augmented with a few other side channels, the team showed that it was possible to fairly accurately track in real time which activity a victim app is in. ‘This method will work on other operating systems because they share a key feature researchers exploited in the Android system,’ Qian noted. The paper was scheduled to be presented at the 23rd USENIX Security Symposium in San Diego on Friday.