CVE-2017-7412 in NixOS
Summary
by MITRE
NixOS 17.03 before 17.03.887 has a world-writable Docker socket, which allows local users to gain privileges by executing docker commands.
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Analysis
by VulDB Data Team • 11/27/2022
The vulnerability described in CVE-2017-7412 represents a critical privilege escalation issue within the NixOS 17.03 operating system distribution. This flaw manifests through a misconfigured Docker socket that is globally writable, creating an insecure access point that local users can exploit to elevate their system privileges. The vulnerability exists specifically in NixOS versions prior to 17.03.887, indicating a targeted issue within a particular release cycle that was subsequently addressed through security updates.
The technical root cause of this vulnerability stems from improper file system permissions on the Docker socket file, which serves as the communication interface between Docker client applications and the Docker daemon. When a socket is configured with world-writable permissions, any local user can establish connections to the Docker daemon and execute commands with the privileges of the Docker daemon process. This creates a direct pathway for privilege escalation since the Docker daemon typically runs with elevated privileges to manage container operations, including access to host system resources and filesystems. The flaw aligns with CWE-732, which describes inadequate permissions for critical resources, and represents a classic example of improper access control in containerized environments.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally compromises the security model of the affected system. Local users who exploit this vulnerability can execute arbitrary Docker commands, potentially gaining access to host system resources, mounting volumes from the host filesystem, or even launching containers that can escape the container boundary to access underlying host resources. This scenario enables attackers to perform actions such as reading sensitive files, modifying system configurations, or establishing persistent access points through container-based persistence mechanisms. The threat landscape is further exacerbated because Docker containers often run with elevated privileges, making this vulnerability particularly dangerous in environments where containerization is prevalent.
Mitigation strategies for CVE-2017-7412 should focus on immediate remediation through updating to NixOS 17.03.887 or later versions where the Docker socket permissions have been properly configured. System administrators should also implement additional security controls such as verifying socket permissions using standard tools like ls -l to ensure that Docker sockets are not world-writable and that appropriate user and group ownership is maintained. The principle of least privilege should be enforced by ensuring that only authorized users have access to Docker commands and that container runtime environments are properly isolated from host resources. Organizations should also consider implementing monitoring and alerting for unauthorized Docker socket access attempts and establish regular security audits to identify and remediate similar permission misconfigurations across their infrastructure. This vulnerability demonstrates the importance of proper privilege management in containerized environments and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploitation of system services.
The broader implications of this vulnerability highlight the increasing complexity of modern operating system security, particularly in containerized environments where multiple layers of access control must be properly configured. It underscores the critical need for security-conscious configuration management and the importance of regular security updates. Organizations should also consider implementing container security solutions that can detect and prevent unauthorized container access attempts, as well as establish security policies that govern the proper handling of container runtime environments. This vulnerability serves as a reminder that even seemingly minor permission misconfigurations can lead to significant security breaches in complex system architectures.