CVE-2016-3084 in Cloud Foundry
Summary
by MITRE
The UAA reset password flow in Cloud Foundry release v236 and earlier versions, UAA release v3.3.0 and earlier versions, all versions of Login-server, UAA release v10 and earlier versions and Pivotal Elastic Runtime versions prior to 1.7.2 is vulnerable to a brute force attack due to multiple active codes at a given time. This vulnerability is applicable only when using the UAA internal user store for authentication. Deployments enabled for integration via SAML or LDAP are not affected.
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Analysis
by VulDB Data Team • 10/03/2020
The vulnerability described in CVE-2016-3084 represents a critical weakness in the User Account and Authentication (UAA) system of Cloud Foundry platforms, specifically affecting password reset functionality. This flaw exists in multiple versions of Cloud Foundry's UAA component and Login-server, creating a significant security risk that can be exploited through brute force attacks. The vulnerability is particularly concerning because it allows attackers to attempt multiple password reset codes simultaneously, effectively bypassing normal rate limiting and account lockout mechanisms that would typically protect against such attacks. The issue is confined to deployments using the UAA internal user store for authentication, which means organizations that have integrated their authentication with external systems such as SAML or LDAP are not vulnerable to this specific attack vector.
The technical root cause of this vulnerability stems from the design flaw in the password reset implementation where multiple active reset codes can exist concurrently for the same user account. This creates a scenario where an attacker can generate numerous reset requests and test multiple codes in parallel, significantly increasing their chances of successfully guessing or brute-forcing a valid reset code. The vulnerability is classified under CWE-307, which addresses improper restriction of repeated access attempts, and aligns with ATT&CK technique T1110.003 for Brute Force Attacks targeting credentials. This design flaw essentially removes the effectiveness of rate limiting controls that should normally prevent automated attack attempts against password reset functions. The concurrent existence of multiple valid codes creates an attack surface where the typical security controls that would limit the number of attempts are rendered ineffective, as there are multiple valid options available for each attack attempt.
The operational impact of this vulnerability extends beyond simple credential compromise, as it can enable attackers to gain unauthorized access to user accounts and potentially escalate privileges within the Cloud Foundry environment. Successful exploitation allows attackers to reset passwords for any user account that has an active UAA internal user store account, potentially leading to full system compromise if the affected accounts have administrative privileges. The vulnerability also impacts the integrity of the authentication system by undermining the trust model that relies on secure password reset mechanisms. Organizations using Cloud Foundry versions prior to 1.7.2, particularly those running UAA releases v236 or earlier, are at risk of unauthorized access, account takeovers, and potential data breaches. The attack requires minimal sophistication but can be highly effective when combined with automated tools that can rapidly test multiple reset codes, making it particularly dangerous in environments with high user volumes or when attackers have knowledge of user account patterns.
Mitigation strategies for CVE-2016-3084 require immediate action to upgrade affected Cloud Foundry components to versions that address the concurrent reset code issue. Organizations should upgrade to Pivotal Elastic Runtime version 1.7.2 or later, UAA release v3.3.1 or later, and ensure that all related components are updated to prevent exploitation. The recommended approach involves implementing proper code expiration mechanisms that ensure only one active reset code exists per user account at any given time, combined with enhanced rate limiting controls that monitor and restrict reset request frequency. Security teams should also consider implementing additional authentication controls such as multi-factor authentication for privileged accounts and monitoring for unusual password reset activity patterns. Network-level controls including IP-based rate limiting and intrusion detection systems can provide additional layers of protection, while regular security audits should verify that the password reset functionality properly enforces single active code policies. Organizations should also review their authentication integration methods to ensure that only the necessary components are exposed to external attack surfaces, as deployments using SAML or LDAP integration are not affected by this specific vulnerability.