CVE-2017-4994 in Cloud Foundry
Summary
by MITRE
An issue was discovered in Cloud Foundry Foundation cf-release versions prior to v263; UAA release 2.x versions prior to v2.7.4.18, 3.6.x versions prior to v3.6.12, 3.9.x versions prior to v3.9.14, and other versions prior to v4.3.0; and UAA bosh release (uaa-release) 13.x versions prior to v13.16, 24.x versions prior to v24.11, 30.x versions prior to 30.4, and other versions prior to v40. There was an issue with forwarded http headers in UAA that could result in account corruption.
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Analysis
by VulDB Data Team • 10/16/2019
The vulnerability described in CVE-2017-4994 represents a critical security flaw within the Cloud Foundry User Account and Authentication (UAA) system that affected multiple release versions prior to specified patches. This issue specifically targeted the handling of forwarded HTTP headers within the UAA component, which serves as the central authentication and authorization service for Cloud Foundry platforms. The vulnerability stems from improper validation and processing of HTTP headers that are typically used in proxy configurations to preserve original client information when requests pass through load balancers or reverse proxies. The flaw allowed malicious actors to manipulate authentication flows by crafting specific HTTP headers that could be interpreted by the UAA service as legitimate authentication requests from trusted sources.
The technical implementation of this vulnerability involves the UAA service's failure to properly sanitize or validate forwarded HTTP headers such as X-Forwarded-For, X-Forwarded-Proto, or similar headers that are commonly used in cloud environments to maintain connection information. When these headers were improperly handled, they could be exploited to bypass authentication mechanisms or manipulate user session data. This particular weakness aligns with CWE-284, which addresses improper access control, and more specifically with CWE-290, which deals with authentication bypass through spoofed headers. The vulnerability creates a path for attackers to potentially impersonate legitimate users or gain unauthorized access to user accounts within the Cloud Foundry environment, ultimately leading to account corruption as indicated in the original description.
The operational impact of CVE-2017-4994 extends beyond simple authentication bypass to encompass potential account compromise and data integrity violations within Cloud Foundry deployments. Organizations utilizing affected UAA versions faced significant risk of unauthorized access to user accounts, particularly in environments where the platform relied on proxy configurations or load balancers for traffic management. The vulnerability could enable attackers to escalate privileges, access sensitive user data, or perform actions within the platform that should have been restricted to authorized users. This risk was particularly severe in multi-tenant environments where account corruption could affect multiple users and potentially lead to broader system compromise. The vulnerability also impacts the integrity of the authentication system itself, as it undermines the trust model that Cloud Foundry relies upon for secure user management and access control.
Mitigation strategies for CVE-2017-4994 require immediate patching of affected UAA releases to versions that properly validate forwarded HTTP headers and implement secure header handling practices. Organizations should upgrade to UAA releases 2.7.4.18, 3.6.12, 3.9.14, and 4.3.0 or later, along with corresponding bosh release versions that address the header validation issues. System administrators must also implement proper network configuration practices that limit direct exposure of UAA components to untrusted networks and ensure that only trusted proxies can forward headers to the authentication service. Additional mitigations include implementing strict header validation policies, monitoring for suspicious header patterns, and establishing network segmentation controls to prevent unauthorized access to authentication components. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and privilege escalation through header manipulation, making it particularly relevant for organizations implementing defensive measures against advanced persistent threats that may exploit such authentication weaknesses.