CVE-2018-1262 in Foundation UAA
Summary
by MITRE
Cloud Foundry Foundation UAA, versions 4.12.X and 4.13.X, introduced a feature which could allow privilege escalation across identity zones for clients performing offline validation. A zone administrator could configure their zone to issue tokens which impersonate another zone, granting up to admin privileges in the impersonated zone for clients performing offline token validation.
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Analysis
by VulDB Data Team • 02/05/2020
The vulnerability identified as CVE-2018-1262 affects Cloud Foundry Foundation's User Account and Authentication (UAA) service version 4.12.X and 4.13.X, representing a critical security flaw that enables unauthorized privilege escalation across identity zones. This issue stems from improper token validation mechanisms that allow malicious actors to exploit configuration weaknesses in the offline validation process. The vulnerability specifically targets the authentication and authorization framework that governs access control within multi-tenant Cloud Foundry environments where multiple identity zones operate under a single UAA instance. When a zone administrator configures their zone to issue tokens that can impersonate another zone, the system fails to properly validate the token's authenticity and zone boundaries, creating a pathway for unauthorized access.
The technical flaw manifests in the offline token validation process where tokens issued by one identity zone can be manipulated to appear as legitimate tokens from another zone. This occurs because the validation logic does not adequately verify the zone context embedded within the token structure, allowing tokens to be validated without proper cross-zone authorization checks. The vulnerability is particularly dangerous because it operates at the core of Cloud Foundry's identity management system, where tokens serve as the primary means of authenticating users and applications across different zones. The flaw enables attackers to leverage legitimate tokens from one zone to gain administrative privileges in another zone, effectively bypassing the intended security boundaries that separate different tenant environments.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of multi-tenant Cloud Foundry deployments. Zone administrators who configure their zones to issue impersonating tokens can grant clients full administrative access to other zones, potentially compromising entire Cloud Foundry instances. This vulnerability affects organizations that rely on Cloud Foundry's multi-tenancy features, as it allows attackers to move laterally between different tenant environments within the same UAA instance. The implications are severe for cloud service providers and enterprises that host multiple customers or departments within a single Cloud Foundry deployment, as unauthorized access to one zone can lead to complete compromise of other zones. The vulnerability also impacts the trust model of the platform, as it allows attackers to impersonate legitimate users and applications across zone boundaries, potentially leading to data breaches, service disruption, and unauthorized resource consumption.
Organizations affected by this vulnerability should immediately implement mitigations including updating to patched versions of UAA, reviewing and restricting zone configuration permissions, and implementing additional validation controls for token issuance. The recommended approach involves disabling the problematic offline validation feature until proper security patches are applied, while also monitoring for unauthorized zone configuration changes. Security teams should conduct comprehensive audits of identity zone configurations to identify any instances where impersonation capabilities might have been enabled. The vulnerability aligns with CWE-284 Access Control Issues, specifically addressing improper access control within multi-tenant environments, and maps to ATT&CK technique T1078 Valid Accounts, as it leverages legitimate authentication mechanisms to gain unauthorized access. Organizations should also consider implementing network segmentation and additional monitoring controls to detect suspicious cross-zone token validation activities, as the vulnerability can be exploited through legitimate administrative tools and APIs that support offline token validation processes.