CVE-2020-29591 in registry Docker Image
Summary
by MITRE • 12/11/2020
Versions of the Official registry Docker images through 2.7.0 contain a blank password for the root user. Systems deployed using affected versions of the registry container may allow a remote attacker to achieve root access with a blank password.
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Analysis
by VulDB Data Team • 12/16/2020
The vulnerability identified as CVE-2020-29591 represents a critical authentication flaw in the Official Docker Registry images that affected versions through 2.7.0. This issue stems from a misconfiguration where the root user account within the registry container is configured with a blank password, creating an inherent security weakness that directly undermines the container's access control mechanisms. The flaw exists at the configuration level within the Docker registry image itself, making it a fundamental design oversight rather than a runtime vulnerability. According to CWE-798, this represents a weakness where hardcoded credentials are present in the software, specifically manifesting as a blank password that provides unrestricted access to the system.
The technical implementation of this vulnerability allows an attacker to gain root access to the registry container simply by authenticating with the root user account and leaving the password field empty. This configuration bypasses all normal authentication procedures and provides immediate administrative privileges within the container environment. The impact extends beyond the immediate container to potentially compromise the underlying host system if proper isolation mechanisms are not in place, as the root access enables full control over the registry operations and potentially the storage of container images and associated metadata. The vulnerability is particularly concerning because it affects the core authentication mechanism of the registry service, which is designed to securely store and distribute container images while maintaining access controls.
The operational impact of this vulnerability is severe for organizations deploying Docker registry containers in production environments. Attackers can exploit this flaw to gain unauthorized access to container image repositories, potentially leading to image tampering, data exfiltration, or the deployment of malicious images into the registry. The blank password creates a backdoor that can be exploited by any remote attacker who knows the registry's location and basic authentication requirements, making the vulnerability highly exploitable in environments where the registry is exposed to untrusted networks. This flaw directly violates security best practices outlined in the NIST SP 800-53 security controls, specifically addressing the need for secure authentication mechanisms and access control management. The vulnerability also aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation through the use of default or weak credentials.
Organizations should immediately update their Docker registry deployments to versions beyond 2.7.0 where this vulnerability has been addressed through proper password configuration. The recommended mitigation strategy involves implementing strong authentication mechanisms including the use of non-blank passwords for root accounts, enabling TLS encryption for registry communications, and implementing network segmentation to limit access to registry services. Additional security measures should include regular security audits of container images, monitoring for unauthorized access attempts, and implementing proper network access controls through firewalls and access control lists. The fix typically involves ensuring that the registry configuration explicitly sets strong passwords for administrative accounts and removes any default or blank credential configurations that could be exploited by attackers. Security teams should also consider implementing automated scanning tools to detect similar credential misconfigurations in other container images and services within their infrastructure.