CVE-2017-14389 in Cloud Foundry
Summary
by MITRE
An issue was discovered in Cloud Foundry Foundation capi-release (all versions prior to 1.45.0), cf-release (all versions prior to v280), and cf-deployment (all versions prior to v1.0.0). The Cloud Controller does not prevent space developers from creating subdomains to an already existing route that belongs to a different user in a different org and space, aka an "Application Subdomain Takeover."
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Analysis
by VulDB Data Team • 12/11/2019
The vulnerability described in CVE-2017-14389 represents a critical authorization flaw within the Cloud Foundry platform's routing system that enables unauthorized subdomain takeover attacks. This issue affects multiple core components including capi-release, cf-release, and cf-deployment across their respective older versions, creating a persistent security weakness that spans the entire Cloud Foundry ecosystem. The flaw specifically resides in the Cloud Controller's inability to properly validate route ownership when space developers attempt to create subdomains, allowing malicious actors to exploit this gap for unauthorized access and potential service disruption.
The technical implementation of this vulnerability stems from insufficient validation mechanisms within the Cloud Controller's route management system. When space developers create subdomains for routes, the system fails to verify whether the parent route already exists and belongs to a different organization and space. This lack of cross-organization route ownership checking creates a scenario where a developer in one organization can claim subdomains that are already registered to routes owned by other organizations. The flaw operates at the application layer and manifests as a failure in the authorization model, specifically in the route creation and validation processes that should enforce proper ownership boundaries between different Cloud Foundry organizations and spaces.
The operational impact of this vulnerability extends beyond simple unauthorized access, creating potential for service disruption, data exposure, and cross-tenant security breaches. Attackers can leverage this vulnerability to redirect traffic intended for legitimate applications to their own malicious endpoints, effectively enabling man-in-the-middle attacks or traffic redirection without proper authorization. The implications are particularly severe in multi-tenant environments where multiple organizations share the same Cloud Foundry instance, as this flaw allows for unauthorized takeover of routing resources that may host sensitive applications or services. This vulnerability directly violates the principle of least privilege and can lead to unauthorized data access, service availability issues, and potential compromise of other tenants' applications.
The security implications of CVE-2017-14389 align with CWE-284, which addresses improper access control, and can be mapped to ATT&CK technique T1071.004 for application layer protocol tunneling and T1190 for exploitation of remote services. Organizations affected by this vulnerability should immediately upgrade to versions 1.45.0 or later for capi-release, v280 or later for cf-release, and v1.0.0 or later for cf-deployment to remediate the issue. Additional mitigations include implementing strict route validation policies, monitoring for unauthorized route creation activities, and ensuring proper segregation of routing resources between different organizations. The vulnerability demonstrates the critical importance of proper authorization enforcement in multi-tenant cloud platforms and underscores the need for comprehensive security testing of core platform components that handle resource allocation and access control.