Researchers recently reported encountering a phishing attack in the wild that bypasses a multifactor authentication scheme based on FIDO (Fast Identity Online), the industry-wide standard being adopted by thousands of sites and enterprises.
If true, the attack, reported in a blog post Thursday by security firm Expel, would be huge news, since FIDO is widely regarded as being immune to credential phishing attacks. After analyzing the Expel write-up, I’m confident that the attack doesn’t bypass FIDO protections, at least not in the sense that the word “bypass” is commonly used in security circles. Rather, the attack downgrades the MFA process to a weaker, non-FIDO-based process. As such, the attack is better described as a FIDO downgrade attack. More about that shortly. For now, let’s describe what Expel researchers reported.
Abusing cross-device sign-ins
Expel said the “novel attack technique” begins with an email that links to a fake login page from Okta, a widely used authentication provider. It prompts visitors to enter their valid user name and password. People who take the bait have now helped the attack group, which Expel said is named PoisonSeed, clear the first big hurdle in gaining unauthorized access to the Okta account.
