CVE-2018-1277 in Garden-runC
Summary
by MITRE
Cloud Foundry Garden-runC, versions prior to 1.13.0, does not correctly enforce disc quotas for Docker image layers. A remote authenticated user may push an app with a malicious Docker image that will consume more space on a Diego cell than allocated in their quota, potentially causing a DoS against the cell.
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Analysis
by VulDB Data Team • 02/01/2020
The vulnerability identified as CVE-2018-1277 affects Cloud Foundry Garden-runC components in versions prior to 1.13.0, representing a critical flaw in container resource management within cloud infrastructure platforms. This issue specifically targets the Diego cell's disk quota enforcement mechanism, which is fundamental to maintaining system stability and resource isolation in multi-tenant environments. The vulnerability exists within the container runtime environment that manages application deployment and execution in Cloud Foundry platforms, where proper resource boundaries must be maintained to prevent one application from consuming resources allocated to others.
The technical flaw manifests in the improper enforcement of disk quotas for Docker image layers during application deployment processes. When users push applications containing malicious Docker images, the system fails to accurately track and limit the actual disk space consumption against the allocated quota. This occurs because the quota enforcement mechanism does not properly account for the layered structure of Docker images, where each layer may consume additional space beyond what is initially allocated. The flaw allows an authenticated attacker to exploit this gap by crafting Docker images that consume more disk space than permitted, effectively bypassing the resource management controls designed to maintain system integrity.
The operational impact of this vulnerability extends beyond simple resource consumption issues, creating significant risks for system availability and stability. A malicious user can deliberately consume excessive disk space on Diego cells, potentially leading to complete system denial of service where legitimate applications cannot be deployed or executed due to insufficient storage resources. This vulnerability particularly affects large-scale Cloud Foundry deployments where multiple applications share the same Diego cell infrastructure, making the impact more severe as the attacker can disrupt services for all applications hosted on the compromised cell. The DoS condition can persist until manual intervention occurs to free up disk space or restart the affected cell, causing operational disruptions and potential revenue loss for cloud service providers.
Mitigation strategies for CVE-2018-1277 require immediate implementation of version upgrades to Garden-runC 1.13.0 or later, which contain the necessary fixes for proper disk quota enforcement. Organizations should also implement additional monitoring and alerting mechanisms to detect unusual disk space consumption patterns on Diego cells, enabling proactive identification of potential exploitation attempts. Network segmentation and access controls should be reinforced to limit the number of authenticated users who can deploy applications, reducing the attack surface. The vulnerability aligns with CWE-1177, which addresses improper enforcement of resource quotas, and maps to ATT&CK technique T1499.004 related to network denial of service attacks. System administrators should also consider implementing automated cleanup processes and regular disk space audits to minimize the impact of any successful exploitation attempts while maintaining operational continuity in cloud environments.