CVE-2017-14388 in Cloud Foundry
Summary
by MITRE
Cloud Foundry Foundation GrootFS release 0.3.x versions prior to 0.30.0 do not validate DiffIDs, allowing specially crafted images to poison the grootfs volume cache. For example, this could allow an attacker to provide an image layer that GrootFS would consider to be the Ubuntu base layer.
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Analysis
by VulDB Data Team • 12/05/2019
The vulnerability identified as CVE-2017-14388 affects Cloud Foundry Foundation GrootFS versions 0.3.x prior to 0.30.0, representing a critical security flaw in container image handling mechanisms. This issue resides within the volume cache management system of GrootFS, which serves as the foundation for container image storage and retrieval in Cloud Foundry environments. The vulnerability stems from insufficient validation of DiffIDs during image layer processing, creating a pathway for malicious actors to manipulate the caching system with crafted image layers.
The technical flaw manifests through the absence of proper DiffID validation, which are cryptographic identifiers used to uniquely identify image layers in container registries. When GrootFS processes image layers without validating these DiffIDs, it becomes susceptible to cache poisoning attacks where attackers can inject malicious or misleading layer information into the system's volume cache. This vulnerability specifically allows attackers to craft image layers that GrootFS incorrectly identifies as legitimate base layers, such as the Ubuntu base layer, thereby compromising the integrity of the container image ecosystem.
The operational impact of this vulnerability extends beyond simple cache corruption, as it fundamentally undermines the trust model of container image repositories within Cloud Foundry deployments. Attackers can exploit this weakness to execute supply chain attacks by substituting legitimate base layers with malicious ones, potentially leading to privilege escalation, data exfiltration, or complete system compromise. The vulnerability affects the core container runtime functionality and can persist across multiple deployments, creating a persistent threat vector that undermines the security posture of affected organizations.
Mitigation strategies should focus on immediate patching to version 0.30.0 or later, which includes proper DiffID validation mechanisms. Organizations should implement comprehensive monitoring of volume cache operations and establish automated scanning processes to detect anomalous image layer behaviors. The vulnerability aligns with CWE-229, which addresses insufficient input validation in software systems, and maps to ATT&CK technique T1059.001 for execution through containerized environments. Additional protective measures include implementing image signature verification, establishing secure image repositories with proper access controls, and conducting regular security assessments of container orchestration platforms to prevent similar vulnerabilities from emerging in related systems.