CVE-2017-20198 in DC OS Marathon
Summary
by MITRE • 07/23/2025
The Marathon UI in DC/OS < 1.9.0 allows unauthenticated users to deploy arbitrary Docker containers. Due to improper restriction of volume mount configurations, attackers can deploy a container that mounts the host's root filesystem (/) with read/write privileges. When using a malicious Docker image, the attacker can write to /etc/cron.d/ on the host, achieving arbitrary code execution with root privileges. This impacts any system where the Docker daemon honors Marathon container configurations without policy enforcement.
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Analysis
by VulDB Data Team • 07/23/2025
The vulnerability described in CVE-2017-20198 represents a critical security flaw in the DC/OS Marathon UI component affecting versions prior to 1.9.0. This issue stems from inadequate authentication mechanisms that allow any unauthenticated user to interact with the Marathon deployment interface, creating an unauthorized attack surface that directly compromises system integrity. The fundamental flaw lies in the improper restriction of volume mount configurations within the container orchestration framework, which enables attackers to manipulate container filesystem mappings without proper authorization controls.
The technical exploitation of this vulnerability occurs through a specific chain of container configuration manipulations that leverage Docker's volume mounting capabilities. Attackers can construct malicious container deployments that map the host's root filesystem to the container with full read-write permissions, effectively creating a direct pathway to the underlying host operating system. This misconfiguration allows the container to access and modify critical system directories, particularly the /etc/cron.d/ directory which serves as a repository for scheduled tasks and system cron jobs. The combination of elevated container privileges with the ability to modify cron configurations creates a persistent execution vector that can be used to establish long-term system compromise.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete system compromise with root-level access. When attackers utilize malicious Docker images in conjunction with the volume mount exploit, they can inject malicious cron jobs that execute with root privileges, effectively allowing them to maintain persistent access to the compromised system. This vulnerability affects any infrastructure running Docker daemon configurations that lack proper policy enforcement mechanisms, making it particularly dangerous in containerized environments where multiple users or services may interact with the container orchestration system. The implications are severe as this vulnerability can be exploited across various deployment scenarios including cloud environments, on-premises data centers, and hybrid infrastructure configurations.
The security implications of CVE-2017-20198 align with CWE-276, which addresses improper file permissions and inadequate access control mechanisms. This vulnerability also maps to ATT&CK technique T1059.001 for command and script injection through cron jobs, and T1068 for privilege escalation through container escape techniques. Organizations should implement strict policy enforcement for container volume mounts, enforce authentication requirements for Marathon UI access, and regularly audit container configurations to prevent unauthorized modifications. The recommended mitigations include upgrading to DC/OS version 1.9.0 or later, implementing network segmentation to restrict access to Marathon UI components, and deploying container runtime policies that prevent host filesystem mounting with elevated privileges. Additionally, organizations should establish comprehensive monitoring for suspicious container deployment activities and implement automated scanning for unauthorized volume mount configurations to detect and prevent exploitation attempts.