The Burmese YGN hacker group on Sunday detailed a URL redirect vulnerability that bypasses Google's notification to users that they might be visiting a malicious site.

The flaw exists in the way that Google checks redirected URLs against a blacklist of known malicious web sites.

The attacker would send a victim a proxy server link which redirected to a malicious URL and, when clicked, would verify if the landing website was blacklisted by Google, researchers said. If it was, the server would generate a second malicious URL to infect users.

Researchers posted a proof-of-concept of the vulnerability on the YGN site.

Google redirect notice:

http://www.google.com/url?sa=t&url=http%3A%2F%2Fattacker.in%2Fmalware_exists_in_this_page%2F.

Bypass:

http://www.google.com/url?sa=t&url=http%3A%2F%2Fattacker.in%2Fmalware_exists_in_this_page%2F&usg=AFQjCNEBtpLqGPICIMz5TJZqfNsZKtHbRg

“The bypass link will last as long as Google doesn't change its internal algorithm that compares the hash against the provided URL,” the researchers wrote.

Google posted tips to mitigate the risk of abuse of open redirect URLs.

This story originally appeared on SC Magazine's Australia site.