CVE-2023-3128 in Grafana
Summary
by MITRE • 06/23/2023
Grafana is validating Azure AD accounts based on the email claim.
On Azure AD, the profile email field is not unique and can be easily modified.
This leads to account takeover and authentication bypass when Azure AD OAuth is configured with a multi-tenant app.
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Analysis
by VulDB Data Team • 11/20/2024
The vulnerability identified as CVE-2023-3128 affects Grafana's authentication mechanism when integrated with Azure Active Directory through OAuth. This security flaw stems from Grafana's reliance on the email claim from Azure AD for account validation and user identification purposes. The core issue lies in the fundamental design of how Azure AD handles email addresses within its directory service, specifically that the profile email field lacks uniqueness guarantees and can be easily modified by users or administrators. When Grafana validates Azure AD accounts using only the email claim without additional verification mechanisms, it creates a critical security gap that can be exploited by malicious actors. The vulnerability becomes particularly pronounced in multi-tenant Azure AD applications where the trust model allows for broader account federation and authentication scenarios.
The technical implementation of this vulnerability occurs when Grafana processes OAuth authentication responses from Azure AD and uses the email field from the authentication token to identify existing users within its system. Since Azure AD allows users to modify their email addresses in their profiles, an attacker who gains access to a valid Azure AD account can simply change the email address associated with that account to match another user's email address within Grafana. This manipulation enables the attacker to impersonate the legitimate user and gain unauthorized access to their Grafana account and associated resources. The flaw represents a classic case of insufficient input validation and authentication verification, where the system accepts a potentially mutable attribute as a definitive user identifier without cross-referencing additional immutable identifiers or implementing proper account mapping logic.
The operational impact of CVE-2023-3128 extends beyond simple unauthorized access, creating potential for significant privilege escalation and data compromise within Grafana environments. Attackers can leverage this vulnerability to perform account takeover attacks against any user whose email address they can predict or obtain, effectively bypassing the authentication controls that should protect Grafana instances. In multi-tenant configurations, the risk amplifies as attackers can potentially target users across different organizations that share the same Grafana instance. The vulnerability also enables lateral movement within Grafana's permission model, allowing attackers to access dashboards, data sources, and other resources that the compromised user has access to. This authentication bypass can lead to complete system compromise if the compromised user has administrative privileges or access to sensitive monitoring data that could be used for further attacks.
Organizations should implement immediate mitigations including updating to Grafana versions that address this vulnerability through enhanced authentication validation mechanisms. The recommended approach involves configuring Grafana to use more reliable user identification methods such as the immutable object identifier or user principal name from Azure AD rather than relying solely on the potentially mutable email field. Security teams should also implement additional verification layers including multi-factor authentication, proper access control policies, and monitoring for suspicious authentication patterns. The vulnerability aligns with CWE-287 which addresses improper authentication issues, and maps to ATT&CK technique T1078 for valid accounts and T1531 for account access removal. Organizations should conduct comprehensive audits of their Azure AD integration settings and review their Grafana user management policies to ensure that authentication flows properly validate user identities through multiple factors rather than relying on a single mutable attribute. Regular security assessments should include verification that authentication systems properly handle scenarios where user profile attributes might be modified or manipulated.