CVE-2018-11041 in Cloud Foundry UAA
Summary
by MITRE
Cloud Foundry UAA, versions later than 4.6.0 and prior to 4.19.0 except 4.10.1 and 4.7.5 and uaa-release versions later than v48 and prior to v60 except v55.1 and v52.9, does not validate redirect URL values on a form parameter used for internal UAA redirects on the login page, allowing open redirects. A remote attacker can craft a malicious link that, when clicked, will redirect users to arbitrary websites after a successful login attempt.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 02/21/2020
The Cloud Foundry User Account and Authentication (UAA) service represents a critical component in cloud infrastructure security, managing user authentication and authorization across enterprise platforms. This vulnerability affects specific versions of the UAA system where the redirect URL validation mechanism fails to properly sanitize input parameters used for internal redirection purposes. The flaw exists within the login page's form processing logic, specifically in how the system handles redirect parameters that are intended to guide users to their intended destination after successful authentication.
The technical implementation of this vulnerability stems from inadequate input validation within the UAA's authentication flow. When users attempt to log in through the UAA interface, the system accepts a redirect parameter that specifies where users should be directed upon successful authentication. However, the validation process fails to properly check or sanitize the value of this parameter, allowing malicious actors to inject arbitrary URLs. This weakness directly maps to CWE-601 Open Redirect vulnerability, which occurs when an application redirects users to external sites without proper validation of the destination URL. The vulnerability affects a specific range of versions including those between 4.6.0 and 4.19.0, excluding certain patch releases, indicating a targeted issue within the UAA's redirect handling mechanism.
The operational impact of this vulnerability presents significant security risks for organizations relying on Cloud Foundry platforms. Attackers can exploit this weakness through social engineering campaigns by crafting malicious links that appear legitimate but redirect users to phishing sites or malicious domains after successful authentication. This creates a dangerous scenario where users believe they are accessing authorized services but are instead redirected to attacker-controlled websites that can harvest credentials, personal information, or corporate data. The attack vector requires minimal technical skill and can be executed through simple URL manipulation, making it particularly dangerous in enterprise environments where users may not be security-aware. The vulnerability essentially undermines the trust model of the authentication system, allowing attackers to bypass normal security controls and potentially gain access to sensitive corporate resources.
Organizations should immediately implement mitigation strategies focusing on version updates and configuration hardening. The primary recommendation involves upgrading to patched versions of the UAA service, specifically those beyond 4.19.0 or the relevant uaa-release versions above v60, while avoiding the excluded patch versions. Additionally, administrators should implement strict input validation for all redirect parameters, ensuring that only pre-approved domains or internal paths are permitted for redirection. Network-level controls including web application firewalls and URL filtering mechanisms can provide additional protection layers. The mitigation approach aligns with ATT&CK technique T1566.001 Phishing, as it addresses the attack vector commonly used to exploit such vulnerabilities. Organizations should also conduct comprehensive security assessments of their Cloud Foundry environments to identify any other potential redirect vulnerabilities and implement proper security monitoring to detect suspicious redirection patterns. Regular security testing and vulnerability scanning should be conducted to maintain ongoing protection against similar weaknesses in authentication systems.