Researchers play cat and mouse with Google's anti-phishing Chrome extension


For the past several days security researchers have raced to demonstrate that phishing protections added by a new Google Chrome extension can be bypassed with ease.

The Password Alert extension, developed by Google and released Wednesday, is designed to alert Chrome users when they input their Gmail passwords on websites that don’t belong to Google and are therefore part of phishing attacks.

By Thursday, an information security consultant named Paul Moore had already devised a method that attackers could use to block the extension’s alerts.

Google fixed that initial bypass in a new version released Friday, but since then it’s been a cat and mouse game between Google’s developers and security researchers who kept finding more and more ways to defeat the extension.

At the moment, the tally stands at nine bypasses, the latest of which was developed by Moore today. According to the researcher, only three of them have been patched by Google so far. The extension’s latest version—1.6—was released Friday.

The majority of these exploits can be resolved easily, but a couple are difficult, if not impossible, to fix, Moore said Monday via email.

For example, an exploit developed by researchers from Dutch software security company Securify works by sandboxing an IFRAME.

“I can’t see how Securify’s sandbox exploit can be resolved without nullifying the sandbox completely,” Moore said. “Likewise, my ‘refresh on keypress’ bypass works by exploiting a race condition which an extension probably cannot resolve.”

In response to these exploits, the head of the webspam team at Google, Matt Cutts, commented on Twitter that: “A world in which every single phisher in the world has to play catchup/counterattack is a better world than today.”

While that might be true, it’s also a bit disingenuous, Moore said. “These exploits, some of which are downright comical, put the user at a disadvantage, not the attacker.”

The extension will protect against the simplest phishing attacks and for that Google should be commended, but it arguably offers little protection against more sophisticated attacks and “no security is better than a false sense of security,” the researcher said.