CVE-2018-1195 in Cloud Foundry
Summary
by MITRE
In Cloud Controller versions prior to 1.46.0, cf-deployment versions prior to 1.3.0, and cf-release versions prior to 283, Cloud Controller accepts refresh tokens for authentication where access tokens are expected. This exposes a vulnerability where a refresh token that would otherwise be insufficient to obtain an access token, either due to lack of client credentials or revocation, would allow authentication.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability described in CVE-2018-1195 represents a critical authentication flaw within the Cloud Foundry Cloud Controller component that affects multiple deployment versions. This issue stems from a fundamental misconfiguration in the token validation process where the system incorrectly accepts refresh tokens in contexts where access tokens should be required. The flaw exists in cf-deployment versions prior to 1.3.0, cf-release versions prior to 283, and Cloud Controller versions prior to 1.46.0, creating a widespread security concern across various Cloud Foundry installations. The technical implementation error allows for a bypass of the expected authentication flow, fundamentally undermining the security model that separates access and refresh token usage within the OAuth 2.0 framework.
The operational impact of this vulnerability extends beyond simple authentication bypasses to create significant security risks for Cloud Foundry environments. When a refresh token is accepted where an access token is expected, it enables unauthorized access even when the refresh token itself would normally be insufficient due to missing client credentials or having been revoked. This creates a scenario where attackers can leverage stale or improperly validated refresh tokens to gain access to protected resources, effectively circumventing the intended token lifecycle management. The vulnerability directly violates the principle of least privilege and can lead to unauthorized data access, privilege escalation, and potential system compromise. This flaw particularly affects environments where refresh tokens have been revoked or where client authentication is required but not properly enforced.
Security professionals should recognize this vulnerability as a classic example of improper authentication handling that aligns with CWE-287, which addresses improper authentication issues in software systems. The flaw also maps to ATT&CK technique T1078.004 which covers valid accounts and T1566.001 for phishing, as it enables attackers to leverage compromised or improperly validated tokens to maintain access. Organizations should immediately implement mitigations including upgrading to patched versions of Cloud Controller, cf-deployment, and cf-release components, enforcing proper token validation mechanisms, and implementing additional monitoring for unauthorized token usage patterns. The vulnerability demonstrates the critical importance of maintaining proper token lifecycle management and ensuring that systems correctly validate token types according to their intended use within OAuth 2.0 frameworks, as failure to do so can result in severe authorization bypass scenarios that compromise entire cloud environments.