CVE-2016-0781 in Cloud Foundry
Summary
by MITRE
The UAA OAuth approval pages in Cloud Foundry v208 to v231, Login-server v1.6 to v1.14, UAA v2.0.0 to v2.7.4.1, UAA v3.0.0 to v3.2.0, UAA-Release v2 to v7 and Pivotal Elastic Runtime 1.6.x versions prior to 1.6.20 are vulnerable to an XSS attack by specifying malicious java script content in either the OAuth scopes (SCIM groups) or SCIM group descriptions.
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Analysis
by VulDB Data Team • 10/03/2020
The vulnerability described in CVE-2016-0781 represents a critical cross-site scripting flaw within the User Account and Authentication (UAA) component of Pivotal Cloud Foundry platforms. This weakness affects multiple versions of the UAA OAuth approval pages, specifically impacting Cloud Foundry versions from v208 through v231, Login-server versions from v1.6 to v1.14, and various UAA releases spanning from v2.0.0 to v3.2.0 along with Pivotal Elastic Runtime 1.6.x versions prior to 1.6.20. The flaw stems from insufficient input validation and output sanitization mechanisms within the OAuth approval interface where users can specify malicious javascript content in either OAuth scopes or SCIM group descriptions, creating a persistent XSS vulnerability that can be exploited by attackers to execute arbitrary code within the context of authenticated user sessions.
The technical implementation of this vulnerability occurs when the UAA OAuth approval pages fail to properly sanitize user-supplied input before rendering it in the web interface. Attackers can craft malicious payloads within SCIM group descriptions or OAuth scopes, which are then stored and subsequently displayed without proper HTML escaping or sanitization. When authenticated users navigate to the approval pages or view the affected scopes and groups, the malicious javascript code executes in their browser context, potentially allowing attackers to steal session cookies, perform actions on behalf of users, or redirect them to malicious sites. This vulnerability operates at the application layer and specifically targets the user interface rendering components of the authentication system, making it particularly dangerous as it can be exploited by attackers who have already gained some level of access to the system through legitimate means.
The operational impact of CVE-2016-0781 extends beyond simple data theft, as successful exploitation can lead to complete compromise of user sessions and potentially broader system access. An attacker who successfully injects malicious javascript code could capture user authentication tokens, access sensitive user data, modify group memberships, or escalate privileges within the Cloud Foundry environment. The vulnerability is particularly concerning in cloud environments where multiple users share the same platform, as a single compromised user account could provide attackers with access to other users' resources and data. The persistence of this vulnerability means that once exploited, malicious code remains active until the affected system is patched or the compromised scopes/groups are removed, potentially allowing attackers to maintain long-term access to the platform.
Organizations affected by this vulnerability should immediately implement patch management procedures to upgrade to versions that contain the necessary security fixes, specifically targeting UAA versions beyond the vulnerable ranges mentioned in the CVE. The remediation strategy should include comprehensive testing of patched versions in staging environments before deployment to production systems, ensuring that no regressions are introduced in the authentication functionality. Additionally, organizations should implement input validation controls at multiple layers of their applications, including web application firewalls and custom sanitization routines, to prevent similar vulnerabilities from manifesting in other components. Security teams should also conduct thorough audits of all user-supplied content within authentication systems and implement proper output encoding for all dynamic content displayed in web interfaces. This vulnerability aligns with CWE-79 Cross-site Scripting and maps to ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, highlighting the need for comprehensive security controls that address both the specific vulnerability and broader exploitation patterns.