CVE-2025-49012 is a medium-severity vulnerability affecting the himmelblau interoperability suite, which integrates Microsoft Azure Entra ID and Intune for identity and access management. The vulnerability arises from improper authentication due to the way himmelblau versions 0.9.0 through 0.9.14 and 1.0.0-alpha handle group-based access restrictions. Specifically, himmelblau introduced support for specifying allowed groups in the `pam_allow_groups` configuration option by group display names rather than immutable object IDs. However, Microsoft Entra ID allows multiple groups to share the same displayName, even permitting non-admin users to create groups with duplicate names depending on tenant settings. This flaw enables an attacker to create a personal group with the same displayName as a legitimate access group (e.g., "Allow-Linux-Login"), add themselves to it, and thereby bypass intended access controls. As a result, the attacker can escalate privileges by gaining authentication or sudo rights on systems protected by himmelblau. The root cause is the reliance on non-unique display names for access control decisions instead of the unique objectId (GUID). The vulnerability does not require user interaction and can be exploited remotely with low complexity, but requires the attacker to have some privileges to create groups in the Entra ID tenant. The issue is fixed in himmelblau version 0.9.15 and later, where group name matching was deprecated and removed in favor of specifying only group objectIds for secure filtering. Mitigation without upgrading involves replacing all `pam_allow_groups` entries with objectIds and auditing the tenant for duplicate display names using Microsoft Graph API. No known exploits are reported in the wild as of the publication date. The CVSS 3.1 base score is 5.4, reflecting medium severity with network attack vector, low attack complexity, and requiring privileges but no user interaction.

For European organizations using himmelblau for Azure Entra ID and Intune interoperability, this vulnerability poses a significant risk of unauthorized privilege escalation. Attackers with limited privileges in the Azure tenant could create spoofed groups to gain elevated access on Linux systems managed via himmelblau, potentially leading to unauthorized administrative access, lateral movement, and compromise of sensitive data or critical infrastructure. Given the widespread adoption of Microsoft Azure services across Europe, organizations relying on himmelblau for identity federation and access control could face breaches impacting confidentiality and integrity of systems. The vulnerability undermines trust in group-based access controls and could disrupt compliance with European data protection regulations such as GDPR if unauthorized access leads to data exposure. The absence of user interaction and the network-based attack vector increase the risk of automated or stealthy exploitation. However, the requirement for some level of privilege to create groups in Entra ID somewhat limits the attacker base, typically to insiders or compromised accounts. Still, the impact on operational security and potential for privilege escalation makes this vulnerability a critical concern for identity and access management in European enterprises.

1. Upgrade himmelblau to version 0.9.15 or later immediately to eliminate support for group name matching and enforce use of immutable objectIds for group filtering. 2. Audit your Microsoft Entra ID tenant using Microsoft Graph API to identify and remediate any duplicate group display names, especially those matching critical access groups. 3. Replace all entries in the `pam_allow_groups` configuration with the unique objectId (GUID) of the target groups instead of display names to prevent spoofing. 4. Review and tighten tenant permissions to restrict the ability to create groups to trusted administrators only, minimizing the risk of malicious group creation. 5. Implement continuous monitoring and alerting for creation of new groups with names matching privileged access groups. 6. Conduct regular access reviews and verify group memberships to detect unauthorized additions. 7. Consider additional multi-factor authentication and just-in-time access controls for privileged operations to reduce risk of compromised accounts exploiting this vulnerability. 8. Document and test incident response procedures for potential privilege escalation incidents related to identity management.