CVE-2019-11279 in UAA
Summary
by MITRE
CF UAA versions prior to 74.1.0 can request scopes for a client that shouldn't be allowed by submitting an array of requested scopes. A remote malicious user can escalate their own privileges to any scope, allowing them to take control of UAA and the resources it controls.
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Analysis
by VulDB Data Team • 12/28/2023
The vulnerability identified as CVE-2019-11279 affects Cloud Foundry User Account and Authentication (UAA) components prior to version 74.1.0, representing a critical authorization flaw that undermines the security posture of cloud platforms relying on this authentication system. This issue stems from improper scope validation within the UAA's client authorization mechanism, where the system fails to adequately verify whether a requesting client has legitimate permissions to access specific scopes. The flaw manifests when a malicious actor submits a crafted array of requested scopes, bypassing the normal authorization checks that should prevent unauthorized access to privileged resources.
The technical implementation of this vulnerability resides in the UAA's scope validation logic, which does not properly enforce scope boundaries for client applications. This weakness allows an attacker to submit a scope array that includes privileges beyond what the client should legitimately possess, effectively enabling privilege escalation attacks. The vulnerability operates at the authorization layer of the UAA system, where scope-based access control should enforce strict boundaries between different levels of system access. According to CWE classification, this represents a weakness in authorization mechanisms, specifically CWE-284 Access Control Bypass, which occurs when an attacker can bypass access control checks to gain unauthorized access to resources.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as successful exploitation grants attackers complete control over the UAA system and all associated resources. This includes the ability to create, modify, or delete user accounts, manage client applications, and access sensitive system information. The implications are particularly severe in cloud environments where UAA serves as the central authentication authority, potentially allowing attackers to compromise entire cloud platforms and the applications running on them. The vulnerability aligns with ATT&CK technique T1078 Valid Accounts, as it enables attackers to leverage legitimate authentication mechanisms to gain elevated privileges within the system.
Organizations affected by this vulnerability should immediately implement mitigation strategies focusing on patch management and access control hardening. The primary remediation involves upgrading to UAA version 74.1.0 or later, which contains the necessary fixes to properly validate scope requests and prevent unauthorized privilege escalation. Additional mitigations include implementing strict scope validation policies, monitoring for unusual scope request patterns, and conducting regular security assessments of authentication systems. Security teams should also review existing client configurations to ensure that scope permissions are properly restricted and that least privilege principles are enforced throughout the system. The vulnerability demonstrates the critical importance of proper authorization controls in identity and access management systems, where a single flaw can provide attackers with complete system compromise capabilities.