CVE-2017-4992 in Cloud Foundry
Summary
by MITRE
An issue was discovered in Cloud Foundry Foundation cf-release versions prior to v261; UAA release 2.x versions prior to v2.7.4.17, 3.6.x versions prior to v3.6.11, 3.9.x versions prior to v3.9.13, and other versions prior to v4.2.0; and UAA bosh release (uaa-release) 13.x versions prior to v13.15, 24.x versions prior to v24.10, 30.x versions prior to 30.3, and other versions prior to v37. There is privilege escalation (arbitrary password reset) with user invitations.
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Analysis
by VulDB Data Team • 10/16/2019
The vulnerability identified as CVE-2017-4992 represents a critical privilege escalation flaw within the Cloud Foundry platform's User Account and Authentication (UAA) system. This weakness affects multiple versions of cf-release and UAA releases, creating a pathway for unauthorized users to gain elevated privileges through user invitation mechanisms. The issue stems from inadequate validation of user invitations and insufficient access controls during the password reset process, allowing malicious actors to manipulate the system's authentication flow.
The technical implementation of this vulnerability resides in the UAA service's handling of user invitation tokens and password reset workflows. When users are invited to join a Cloud Foundry organization or space, the system generates invitation tokens that should be strictly validated before allowing any password reset operations. However, the flawed implementation permits attackers to forge or manipulate these tokens, enabling them to reset passwords for arbitrary user accounts without proper authorization. This represents a direct violation of the principle of least privilege and undermines the fundamental security model of the platform.
From an operational impact perspective, this vulnerability creates a severe risk landscape for Cloud Foundry deployments. Attackers can exploit this weakness to gain unauthorized access to user accounts, potentially escalating their privileges to administrative levels within the platform. The vulnerability affects the entire UAA ecosystem, making it particularly dangerous for organizations that rely heavily on Cloud Foundry for their application hosting and management. The attack vector is relatively straightforward, requiring only knowledge of the invitation mechanism and basic understanding of how the UAA service processes password reset requests.
The vulnerability aligns with CWE-284, which addresses improper access control issues, and specifically relates to CWE-287, which deals with improper certificate validation. Additionally, this weakness maps to ATT&CK technique T1078, which covers valid accounts usage, as attackers can leverage legitimate invitation mechanisms to gain unauthorized access. Organizations deploying Cloud Foundry should prioritize immediate remediation of affected versions, particularly those running UAA releases before the specified patch versions including 2.7.4.17, 3.6.11, 3.9.13, and 4.2.0. The fix requires implementing proper token validation, enforcing strict access controls during password reset operations, and ensuring that invitation mechanisms cannot be exploited to manipulate user account privileges. Organizations should also consider implementing network segmentation and monitoring for unusual invitation and password reset activities to detect potential exploitation attempts.