CVE-2016-0928 in Cloud Foundry Elastic Runtime
Summary
by MITRE
Multiple open redirect vulnerabilities in Pivotal Cloud Foundry (PCF) Elastic Runtime before 1.6.30 and 1.7.x before 1.7.8 allow remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via unspecified vectors.
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Analysis
by VulDB Data Team • 04/18/2019
The vulnerability identified as CVE-2016-0928 represents a critical open redirect flaw within Pivotal Cloud Foundry's Elastic Runtime platform, affecting versions prior to 1.6.30 and 1.7.x prior to 1.7.8. This issue stems from inadequate input validation and sanitization mechanisms within the platform's authentication and authorization workflows, creating a pathway for malicious actors to manipulate redirect URLs that are typically used during login and logout processes. The vulnerability operates at the application layer and specifically targets the platform's handling of redirect parameters that are commonly employed to direct users back to their intended destinations after authentication events. Such flaws are particularly dangerous in cloud environments where multiple applications and services interact through shared authentication mechanisms, as they can be exploited to bypass normal security controls and redirect users to malicious domains.
The technical implementation of this vulnerability allows attackers to craft specially formatted URLs that contain malicious redirect parameters, which when processed by the affected PCF components, will cause legitimate user sessions to be redirected to attacker-controlled websites. This occurs because the platform fails to properly validate or sanitize the redirect URLs against a whitelist of approved domains or to ensure that the destination URLs are within the trusted network boundaries of the organization. The flaw is categorized under CWE-601 as Open Redirect, which is a well-documented weakness in web applications where user-supplied input can be used to redirect users to external sites without proper validation. The vulnerability's impact is amplified by the fact that it affects the core Elastic Runtime component, which serves as the foundation for numerous applications and services within the PCF ecosystem, making it a prime target for attackers seeking to compromise user sessions across multiple applications.
From an operational perspective, this vulnerability enables sophisticated phishing attacks where users are tricked into believing they are accessing legitimate services while actually being redirected to malicious sites designed to capture credentials or personal information. The attack vector typically involves social engineering elements where users receive emails or links that appear to be from trusted sources, but when clicked, redirect them to attacker-controlled domains. The implications extend beyond simple credential theft, as the vulnerability can be leveraged to deliver malware, conduct account takeover attacks, or perform other malicious activities that exploit the trust relationship between the user and the platform. This particular vulnerability aligns with ATT&CK technique T1566.001 which describes the use of spearphishing with links, and the broader category of credential access attacks that target user authentication flows within cloud environments.
Organizations utilizing affected versions of Pivotal Cloud Foundry should implement immediate mitigations including applying the vendor patches released in versions 1.6.30 and 1.7.8, which contain proper input validation and redirect URL sanitization mechanisms. Additional defensive measures include implementing strict URL validation policies that enforce redirects only to pre-approved domains, deploying web application firewalls with open redirect detection capabilities, and conducting comprehensive security testing of authentication flows. Network-level controls such as DNS filtering and outbound traffic monitoring can also help detect and prevent exploitation attempts. The vulnerability demonstrates the importance of input validation in cloud-native applications and highlights the need for organizations to maintain up-to-date security patches for their platform components, particularly those handling authentication and session management functions. Security teams should also consider implementing user education programs to recognize potential phishing attempts that may exploit such vulnerabilities, as the human element remains a critical factor in successful exploitation of open redirect vulnerabilities.