Google has published an extension for its Chrome browser that fixes a serious security hole that can reveal a user's real IP address even though they're using a VPN. The vulnerability was made headlines in early 2015 and caused a wave of panic but Chrome users can now mitigate the problem with few clicks.

As large numbers of Internet users wise up to seemingly endless online privacy issues, security products are increasingly being viewed as essential for even basic tasks such as web browsing.

In addition to regular anti-virus, firewall and ad-busting products, users wishing to go the extra mile often invest in a decent VPN service which allow them to hide their real IP addresses from the world. Well that’s the theory at least.

January this year details of a serious vulnerability revealed that in certain situations third parties were able to discover the real IP addresses of Chrome and Firefox users even though they were connected to a VPN.

This wasn’t the fault of any VPN provider though. The problem was caused by features present in WebRTC, an open-source project supported by Google, Mozilla and Opera.

By placing a few lines of code on a website and using a STUN server it became possible to reveal not only users’ true IP addresses, but also their local network address too.

While users were immediately alerted to broad blocking techniques that could mitigate the problem, it’s taken many months for the first wave of ‘smart’ solutions to arrive.

Following on the heels of a Chrome fix published by Rentamob earlier this month which protects against VPN leaks while leaving WebRTC enabled, Google has now thrown its hat into the ring.

Titled ‘WebRTC Network Limiter‘, the tiny Chrome extension (just 7.31KB) disables the WebRTC multiple-routes option in Chrome’s privacy settings while configuring WebRTC not to use certain IP addresses.

In addition to hiding local IP addresses that are normally inaccessible to the public Internet (such as 192.168.1.1), the extension also stops other public IP addresses being revealed.

“Any public IP addresses associated with network interfaces that are not used for web traffic (e.g. an ISP-provided address, when browsing through a VPN) [are hidden],” Google says.

“Once the extension is installed, WebRTC will only use public IP addresses associated with the interface used for web traffic, typically the same addresses that are already provided to sites in browser HTTP requests.”

While both the Google and Rentamob solutions provide more elegant responses to the problem than previously available, both admit to having issues.

“Some WebRTC functions, like VOIP, may be affected by the multiple routes disabled setting. This is unavoidable,” Rentamob explains.

Google details similar problems, including issues directly linked to funneling traffic through a VPN.

“This extension may affect the performance of applications that use WebRTC for audio/video or real-time data communication. Because it limits the potential network paths, WebRTC may pick a path that results in significantly longer delay or lower quality (e.g. through a VPN). We are attempting to determine how common this is,” the company concludes.

After applying the blocks and fixes detailed above, Chrome users can check for IP address leaks by using sites including IPLeak and BrowserLeaks.