CVE-2017-2673 in OpenStack Identity
Summary
by MITRE
An authorization-check flaw was discovered in federation configurations of the OpenStack Identity service (keystone). An authenticated federated user could request permissions to a project and unintentionally be granted all related roles including administrative roles.
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Analysis
by VulDB Data Team • 04/18/2023
The vulnerability identified as CVE-2017-2673 represents a critical authorization flaw within the OpenStack Identity service known as keystone. This issue specifically affects federated authentication configurations where users from external identity providers can access OpenStack environments through trust relationships. The flaw stems from inadequate validation of role assignments during federated user authentication processes, creating a privilege escalation vector that allows malicious actors to gain unauthorized administrative access.
The technical implementation of this vulnerability resides in the keystone service's handling of federated identity claims and role mapping. When federated users authenticate through external identity providers such as Active Directory or LDAP systems, the keystone service processes role assignments based on attributes received from these providers. The flaw occurs because keystone fails to properly validate or restrict the scope of roles assigned to federated users, allowing them to inherit administrative privileges that should be restricted to local users only. This misconfiguration enables attackers to bypass normal access controls and escalate their privileges within the OpenStack environment.
The operational impact of this vulnerability extends beyond simple privilege escalation, creating significant risks for cloud infrastructure security. Federated users who should only have limited project access can inadvertently be granted full administrative capabilities across projects, potentially compromising entire cloud deployments. Attackers could exploit this flaw to gain control over virtual machine instances, storage resources, network configurations, and other critical cloud components. The vulnerability affects organizations using OpenStack's federation features, particularly those implementing single sign-on solutions with external identity providers, making it a widespread concern for cloud security administrators.
Organizations should implement immediate mitigations including updating to patched versions of OpenStack keystone, reviewing and tightening federated identity mappings, and implementing stricter role assignment policies. The vulnerability aligns with CWE-284 which addresses improper access control in software systems, and maps to ATT&CK technique T1078.101 for valid accounts with elevated privileges. Security teams must conduct comprehensive audits of federated authentication configurations, implement principle of least privilege for federated users, and monitor access logs for suspicious administrative activity. Additionally, organizations should consider implementing multi-factor authentication for federated accounts and regularly review role assignments to prevent unauthorized privilege escalation scenarios.