CVE-2017-8033 in Cloud Foundry
Summary
by MITRE
An issue was discovered in the Cloud Controller API in Cloud Foundry Foundation CAPI-release versions prior to v1.35.0 and cf-release versions prior to v268. A filesystem traversal vulnerability exists in the Cloud Controller that allows a space developer to escalate privileges by pushing a specially crafted application that can write arbitrary files to the Cloud Controller VM.
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Analysis
by VulDB Data Team • 11/01/2019
The vulnerability identified as CVE-2017-8033 represents a critical filesystem traversal flaw within the Cloud Controller API component of Cloud Foundry's CAPI-release system. This security weakness affects versions prior to v1.35.0 in CAPI-release and v268 in cf-release, creating a significant risk for cloud platform environments that rely on Cloud Foundry's infrastructure. The vulnerability stems from inadequate input validation and path handling mechanisms within the application deployment process, specifically when processing application manifests and file structures during the push operation.
The technical exploitation of this vulnerability occurs through a carefully crafted application package that leverages symbolic links or directory traversal sequences to bypass normal file system access controls. When a space developer pushes an application with maliciously constructed file paths or symbolic links, the Cloud Controller's file handling logic fails to properly sanitize these inputs, allowing the malicious application to write files to arbitrary locations within the Cloud Controller's file system. This flaw operates at the intersection of privilege escalation and unauthorized file system access, enabling attackers to potentially overwrite critical system files, inject malicious code, or establish persistent backdoors within the platform infrastructure.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations within Cloud Foundry environments. Attackers who successfully exploit this vulnerability can gain unauthorized access to the Cloud Controller VM's file system, potentially allowing them to modify core platform components, access sensitive configuration files, or establish persistent access points. This threat vector directly impacts the security posture of cloud platforms that depend on Cloud Foundry, as it enables attackers with space developer privileges to elevate their access level and potentially compromise the entire platform infrastructure. The vulnerability's impact is particularly severe because it allows attackers to operate within the same privileged context as the Cloud Controller service itself.
Mitigation strategies for CVE-2017-8033 primarily involve immediate upgrades to supported versions of Cloud Foundry's CAPI-release and cf-release components, specifically targeting versions v1.35.0 and v268 respectively. Organizations should implement comprehensive input validation measures and file path sanitization within their application deployment pipelines to prevent malicious file structures from being processed. The implementation of strict file system access controls and mandatory code review processes for application manifests can significantly reduce the risk of exploitation. Additionally, organizations should consider implementing network segmentation and monitoring solutions to detect anomalous file system access patterns that might indicate exploitation attempts. This vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and represents a classic example of how inadequate input validation can lead to privilege escalation in cloud infrastructure platforms. The attack pattern associated with this vulnerability follows ATT&CK technique T1059 (Command and Scripting Interpreter) and T1078 (Valid Accounts) as attackers leverage legitimate developer accounts to execute malicious payloads within the platform's trusted environment.