CVE-2015-7225 in Devise-two-factor
Summary
by MITRE
Tinfoil Devise-two-factor before 2.0.0 does not strictly follow section 5.2 of RFC 6238 and does not "burn" a successfully validated one-time password (aka OTP), which allows remote or physically proximate attackers with a target user's login credentials to log in as said user by obtaining the OTP through performing a man-in-the-middle attack between the provider and verifier, or shoulder surfing, and replaying the OTP in the current time-step.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2015-7225 affects Tinfoil Devise-two-factor authentication client versions prior to 2.0.0, representing a critical flaw in the implementation of time-based one-time password (TOTP) protocols. This issue stems from the application's failure to properly adhere to section 5.2 of RFC 6238, which establishes the standard for TOTP algorithm implementation. The core technical problem lies in the client's inability to "burn" or invalidate successfully validated one-time passwords, creating a persistent security weakness that fundamentally undermines the time-sensitive nature of TOTP authentication mechanisms.
The operational impact of this vulnerability is severe and exploitable through multiple attack vectors including man-in-the-middle attacks and shoulder surfing techniques. Attackers who obtain a user's login credentials can leverage this flaw to gain unauthorized access by capturing a valid OTP during the authentication process and replaying it within the current time window. This represents a significant deviation from the expected behavior of secure two-factor authentication systems where each OTP should be consumed and invalidated upon successful verification. The vulnerability effectively transforms a time-bound security mechanism into a reusable credential, eliminating the primary security benefit of TOTP implementations.
From a cybersecurity perspective, this vulnerability aligns with CWE-310, which addresses cryptographic weaknesses in authentication systems, and specifically demonstrates the dangers of improper implementation of cryptographic protocols. The attack surface is particularly concerning as it can be exploited remotely or through physical proximity, making it accessible to a wide range of threat actors. The flaw directly violates the fundamental principle of time-based one-time passwords, which should only be valid for a single authentication attempt within a specific time window. This misimplementation creates a persistent backdoor that allows attackers to repeatedly use the same OTP, fundamentally compromising the security model of two-factor authentication.
The recommended mitigation strategy involves upgrading to Tinfoil Devise-two-factor version 2.0.0 or later, which properly implements the RFC 6238 specification and enforces proper OTP consumption. Organizations should also implement additional monitoring for suspicious authentication patterns and consider deploying network-level protections against man-in-the-middle attacks. The vulnerability serves as a reminder of the critical importance of strict adherence to established security standards and the potential consequences of incomplete protocol implementation in authentication systems. Security teams must ensure that all authentication components properly validate and consume one-time passwords to maintain the integrity of multi-factor authentication frameworks.