Passkey technology is increasingly used to protect online accounts, but many accounts in banking, e-commerce, social media, and other platforms remain vulnerable to adversary-in-the-middle (AitM) attacks. Joe Stewart from eSentire’s Threat Response Unit explains that the issue lies not in the passkeys themselves but in their implementation and the necessity for account recovery options. Many websites offer less-secure backup authentication methods, which attackers exploit by manipulating login screens to remove the passkey option, thereby forcing users to use weaker authentication methods.
In proof-of-concept attacks, Stewart demonstrated how AitM tactics could easily modify login pages to hide the passkey option, compelling users to revert to username and password logins. These attacks allow hackers to intercept credentials and maintain persistent access to accounts. Even when passkeys are used as a second authentication factor, attackers can manipulate the login process to bypass this security measure, making most current implementations vulnerable.
The problem isn’t due to flaws in passkey technology but rather the immaturity of authentication methods and the need for account recovery options. Users are often unfamiliar with passkeys and can’t recognize manipulated login pages, while implementers may overlook how AitM can alter the login view. Recovery options, though necessary for lost devices, are typically vulnerable to AitM attacks, making it challenging to maintain secure authentication.
Stewart suggests that enterprises can adopt several measures to protect against these attacks, including using magic links for account recovery, conditional access policies, and encouraging users to add multiple passkeys. Despite these recommendations, the widespread use of less-secure backup methods remains a significant hurdle in fully securing online accounts against AitM attacks.
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