CVE-2018-1193 in Cloud Foundry
Summary
by MITRE
Cloud Foundry routing-release, versions prior to 0.175.0, lacks sanitization for user-provided X-Forwarded-Proto headers. A remote user can set the X-Forwarded-Proto header in a request to potentially bypass an application requirement to only respond over secure connections.
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Analysis
by VulDB Data Team • 02/08/2020
The vulnerability identified as CVE-2018-1193 resides within the Cloud Foundry routing-release component, specifically affecting versions prior to 01750. This issue represents a critical security flaw that undermines the integrity of secure communication protocols within cloud environments. The vulnerability stems from insufficient input validation and sanitization mechanisms within the routing layer, which processes HTTP headers from incoming requests. When applications deployed on Cloud Foundry require secure connections through HTTPS, the system should enforce this requirement by validating the actual protocol being used for communication. However, the flawed implementation allows malicious actors to manipulate the X-Forwarded-Proto header, which is typically used to identify the original protocol (http or https) that was used to reach a load balancer or proxy server.
The technical exploitation of this vulnerability occurs through manipulation of the X-Forwarded-Proto HTTP header value in client requests. Attackers can craft requests that contain a spoofed X-Forwarded-Proto header set to "https" even when the actual connection is insecure, potentially bypassing application-level security controls that enforce HTTPS-only communication. This flaw operates at the network layer of the application stack, specifically targeting the routing mechanisms that handle header processing and protocol validation. The vulnerability is classified under CWE-20, which deals with improper input validation, and represents a classic case of header manipulation that can lead to protocol downgrade attacks or bypass of security controls. The routing-release component in Cloud Foundry serves as a critical intermediary between clients and backend applications, making this vulnerability particularly dangerous as it can affect multiple applications running within the same platform instance.
The operational impact of CVE-2018-1193 extends beyond simple protocol confusion, potentially enabling more sophisticated attacks that exploit the trust relationship between the routing layer and applications. Applications that rely on the X-Forwarded-Proto header for security decisions may be deceived into treating insecure connections as secure, leading to potential data exposure, session hijacking, or bypass of authentication mechanisms. This vulnerability particularly affects applications that implement security policies based on protocol requirements, such as those enforcing HTTPS for sensitive data transmission or those that redirect HTTP traffic to HTTPS. The implications are significant in multi-tenant cloud environments where the routing layer acts as a gateway for numerous applications, as a single compromised header could potentially affect the security posture of multiple applications simultaneously. The vulnerability also aligns with ATT&CK technique T1071001, which involves application layer protocol manipulation, and represents a common vector for protocol-based attacks in cloud infrastructure environments.
Organizations affected by this vulnerability should immediately upgrade their Cloud Foundry routing-release components to version 01750 or later, which includes proper sanitization of the X-Forwarded-Proto header. The mitigation strategy should also involve implementing additional security controls such as validating the source of headers through trusted proxy configurations, implementing proper header filtering at the network level, and conducting regular security assessments of routing components. Security teams should also consider implementing monitoring solutions that can detect anomalous header values and establish proper incident response procedures for handling potential exploitation attempts. The fix implemented in version 01750 addresses the root cause by ensuring that the routing layer properly sanitizes and validates the X-Forwarded-Proto header before passing it to backend applications, thereby preventing malicious manipulation of security-critical protocol information. Additionally, organizations should review their overall Cloud Foundry security configuration to ensure that all components are properly updated and that security policies are consistently enforced across the entire platform infrastructure.