CVE-2024-21632 in omniauth-microsoft_graph
Summary
by MITRE • 01/03/2024
omniauth-microsoft_graph provides an Omniauth strategy for the Microsoft Graph API. Prior to versions 2.0.0, the implementation did not validate the legitimacy of the `email` attribute of the user nor did it give/document an option to do so, making it susceptible to nOAuth misconfiguration in cases when the `email` is used as a trusted user identifier. This could lead to account takeover. Version 2.0.0 contains a fix for this issue.
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Analysis
by VulDB Data Team • 01/23/2024
The vulnerability described in CVE-2024-21632 affects the omniauth-microsoft_graph gem, which provides an authentication strategy for integrating with Microsoft Graph API through the Omniauth framework. This gem serves as a bridge between applications and Microsoft's identity services, enabling single sign-on functionality and user authentication through Microsoft accounts. The flaw exists in versions prior to 2.0.0 where the implementation fails to properly validate the email attribute received from Microsoft's authentication responses, creating a significant security gap that could be exploited by malicious actors.
The technical flaw stems from insufficient input validation within the authentication flow where the gem accepts email addresses from Microsoft's API without performing proper verification of their authenticity or legitimacy. This misconfiguration occurs because the system treats the email attribute as a trusted identifier without implementing checks to ensure it originated from a legitimate Microsoft authentication source. The vulnerability is classified as a nOAuth misconfiguration issue where the email field becomes a vector for account takeover attacks, as attackers can potentially manipulate or forge email values in authentication responses.
The operational impact of this vulnerability is severe and directly relates to authentication bypass and account takeover capabilities. When applications rely on the email attribute from omniauth-microsoft_graph for user identification and access control, malicious actors can exploit this weakness to assume the identity of legitimate users. This creates a pathway for unauthorized access to protected resources, potential data breaches, and compromise of user accounts within systems that depend on this authentication mechanism. The vulnerability particularly affects applications that use email addresses as primary user identifiers for session management, access control, and privilege assignment.
The fix implemented in version 2.0.0 addresses this security gap by introducing proper validation mechanisms for the email attribute. This update ensures that email values received from Microsoft's authentication API are verified against legitimate sources and that applications can configure appropriate validation options. Organizations should immediately upgrade to version 2.0.0 or later to remediate this vulnerability and prevent potential exploitation. The mitigation strategy also involves reviewing existing authentication flows to ensure proper validation of user attributes and implementing additional security controls such as multi-factor authentication to reduce the impact of potential credential compromise. This vulnerability aligns with CWE-284 (Improper Access Control) and follows ATT&CK techniques related to credential access and privilege escalation through authentication system weaknesses.