CVE-2017-15611 in Octopus
Summary
by MITRE
In Octopus before 3.17.7, an authenticated user who was explicitly granted the permission to invite new users (aka UserInvite) can invite users to teams with escalated privileges.
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Analysis
by VulDB Data Team • 01/04/2023
The vulnerability identified as CVE-2017-15611 affects Octopus Deploy versions prior to 3.17.7, representing a critical privilege escalation flaw within the user management system. This issue specifically targets the authorization mechanisms that govern user invitation and team assignment capabilities within the platform. The vulnerability exists in the permission validation logic that controls how users with specific roles can invite new team members, creating an unintended pathway for privilege escalation that directly impacts the system's security posture.
The technical flaw manifests in the insufficient validation of team assignment permissions during the user invitation process. When an authenticated user possesses the explicit permission to invite new users, the system fails to properly verify whether the inviting user has the appropriate authorization level to assign the invited user to teams with elevated privileges. This authorization bypass occurs because the invitation system does not enforce proper access controls when determining which teams a newly invited user can be associated with, allowing users with limited permissions to effectively grant themselves or others access to higher-privileged team memberships.
The operational impact of this vulnerability extends beyond simple privilege escalation, creating potential security risks that could compromise the integrity of the deployment environment. An attacker with UserInvite permissions could systematically invite users to teams with administrative or sensitive access levels, effectively bypassing the intended role-based access controls that are fundamental to maintaining security boundaries within deployment systems. This flaw undermines the principle of least privilege and could enable unauthorized access to critical deployment resources, configuration management, and sensitive environment variables that are typically restricted to privileged users.
This vulnerability aligns with CWE-284, which addresses improper access control, and represents a specific instance of insufficient authorization checks in user management systems. The flaw also relates to ATT&CK technique T1078 which covers valid accounts and privilege escalation through unauthorized access to system resources. Organizations using Octopus Deploy are particularly vulnerable if they have granted UserInvite permissions to users who should not have access to sensitive teams, as this creates a persistent backdoor for privilege escalation attacks.
The recommended mitigation strategy involves upgrading to Octopus Deploy version 3.17.7 or later, which includes proper authorization validation during the user invitation process. Additionally, organizations should conduct immediate reviews of existing user permissions to ensure that the UserInvite capability is not granted to users who should not have the potential to escalate privileges through team assignments. Network segmentation and monitoring of user invitation activities can provide additional layers of defense, while regular security audits of permission assignments should be implemented to prevent similar authorization bypass vulnerabilities from occurring in other system components.