Forgot Password? Man-in-the-Middle Attack Can Perform a Password Reset, Researchers Warn

June 26, 2017 @ 1:40 PM
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2 min read

The Institute of Electrical and Electronic Engineers (IEEE) recently published a paper detailing a new type of man-in-the-middle (MitM) attack that enables malicious actors to perform password resets on victims’ devices.

In their paper, “The Password Reset MitM Attack,” researchers from the College of Management Academic Studies, Israel, explained that cybercriminals could exploit the similarities between the registration and password reset processes to compromise accounts on a number of popular websites and mobile messaging applications, including Snapchat, Yahoo, Google, LinkedIn and Facebook.

Unmasking the Man in the Middle

To carry out this kind of attack, a threat actor must first control a website that a victim wishes to access, according to Help Net Security. After the victim registers with the site to gain access, the attacker steals his or her information to initiate a password reset on another site, which typically does not require the original password.

The target site prompts the victim to respond to security questions, the answers of which end up in the attacker’s hands.

Bypassing 2FA

Some sites use SMS-based two-factor authentication (2FA) to add a level of complexity to the password reset process. Like most security measures, however, cybercriminals have figured out a tricky way to beat it.

First, the attack site prompts the user to enter his or her phone number, ostensibly for verification. Next, the victim received a security code from the target site in a text message. That code is then passed, inadvertently, from the victim to the threat actor, who can use it to harvest the reset password.

According to the researchers, many users ignore the origin of the 2FA message, even if it comes from an unexpected source.

Reinforcing the Password Reset Process

The researchers advised affected organizations to avoid using static security questions on their sites and to render password reset codes invalid after a short time. Online services should also add email notifications to the reset process. Finally, users should be required to click a link, not just enter a code, to activate a new password.

Although the researchers did not report any actual attacks that have used this method, their analysis of potential vulnerabilities should put security professionals on notice.

Larry Loeb
Principal, PBC Enterprises

Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE mag...
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