CVE-2023-0629 in Docker
Summary
by MITRE • 03/13/2023
Docker Desktop before 4.17.0 allows an unprivileged user to bypass Enhanced Container Isolation (ECI) restrictions by setting the Docker host to docker.raw.sock, or npipe:////.pipe/docker_engine_linux on Windows, via the -H (--host) CLI flag or the DOCKER_HOST environment variable and launch containers without the additional hardening features provided by ECI. This would not affect already running containers, nor containers launched through the usual approach (without Docker's raw socket). The affected functionality is available for Docker Business customers only and assumes an environment where users are not granted local root or Administrator privileges. This issue has been fixed in Docker Desktop 4.17.0. Affected Docker Desktop versions: from 4.13.0 before 4.17.0.
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Analysis
by VulDB Data Team • 03/13/2023
The vulnerability described in CVE-2023-0629 represents a significant security regression in Docker Desktop's Enhanced Container Isolation (ECI) mechanism, which is designed to provide additional security hardening for containerized applications. This flaw specifically affects Docker Desktop versions between 4.13.0 and 4.17.0, creating a pathway for unprivileged users to circumvent the security controls that are normally enforced when ECI is enabled. The vulnerability operates through a fundamental design flaw that allows users to bypass the isolation boundaries by manipulating the Docker host endpoint configuration, effectively undermining the security model that was intended to protect against container escape attacks and privilege escalation attempts.
The technical exploitation of this vulnerability relies on the ability of an unprivileged user to set the Docker host to specific raw socket endpoints using either the -H (--host) CLI flag or the DOCKER_HOST environment variable. On Linux systems, this involves setting the host to docker.raw.sock, while Windows systems require the npipe:////.pipe/docker_engine_linux endpoint. This manipulation allows attackers to establish connections directly to the Docker daemon's raw socket interface, bypassing the normal containerization security boundaries that ECI would typically enforce. The vulnerability is particularly concerning because it operates at the transport layer of Docker's communication mechanism, allowing direct access to the underlying container runtime without the additional security checks that ECI normally provides. This represents a violation of the principle of least privilege and demonstrates a failure in Docker's access control implementation, with the flaw being categorized under CWE-284 Access Control Issues, specifically related to insufficient access control mechanisms.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security posture of environments where ECI is enabled. Even though the issue does not affect already running containers or those launched through normal Docker operations, it creates a persistent backdoor that allows unprivileged users to launch new containers with reduced security protections. This capability is particularly dangerous in enterprise environments where Docker Business customers expect enhanced security controls to prevent lateral movement and privilege escalation attacks. The vulnerability assumes an environment where local root or Administrator privileges are not granted to regular users, but it still represents a significant downgrade in security posture since it allows users to bypass security controls that are specifically designed to prevent such scenarios. The attack vector aligns with ATT&CK technique T1059 Command and Scripting Interpreter, where adversaries use legitimate system tools to execute commands with elevated privileges, and T1068 Exploitation for Privilege Escalation, where the vulnerability enables unauthorized access to enhanced container features.
The mitigation strategy for this vulnerability requires immediate upgrading to Docker Desktop version 4.17.0 or later, which addresses the core issue by properly enforcing access controls on raw socket endpoints. Organizations should also implement monitoring for unusual Docker host endpoint configurations and establish policies that prevent unprivileged users from setting custom Docker host endpoints. Security teams should conduct comprehensive audits of their Docker Desktop installations to identify affected versions and ensure proper patching across all systems. The vulnerability highlights the importance of maintaining up-to-date security controls and demonstrates the critical need for proper access control mechanisms in containerized environments. Additionally, organizations should consider implementing network segmentation and additional monitoring for Docker socket access to detect potential exploitation attempts. This vulnerability serves as a reminder of the complex security considerations involved in container orchestration platforms and the need for continuous security assessment and patch management processes. The fix implemented in Docker Desktop 4.17.0 likely involves strengthening the validation of host endpoint configurations and ensuring that raw socket access is properly restricted based on user privileges, thereby maintaining the integrity of the ECI security model.