CVE-2014-6407 in Docker
Summary
by MITRE
Docker before 1.3.2 allows remote attackers to write to arbitrary files and execute arbitrary code via a (1) symlink or (2) hard link attack in an image archive in a (a) pull or (b) load operation.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 04/07/2022
The vulnerability identified as CVE-2014-6407 represents a critical security flaw in Docker containerization software prior to version 1.3.2. This issue stems from insufficient validation of file system operations during image archive processing, specifically when handling symbolic links and hard links. The vulnerability enables remote attackers to manipulate file system structures within container images, creating a pathway for arbitrary file writes and code execution. The attack vectors involve both pull and load operations where Docker processes image archives containing malicious link structures that can be exploited to compromise host systems.
The technical implementation of this vulnerability exploits the fundamental trust model between Docker and image archives, where symbolic and hard links are not properly sanitized during decompression. When Docker processes an image archive containing malicious symlinks or hard links, it can inadvertently create file system entries that point to arbitrary locations on the host system. This occurs because the container engine does not adequately validate the target paths of these links, allowing attackers to craft archives that, when processed, can overwrite critical system files or create backdoor access points. The flaw particularly affects the tar extraction process where Docker unpacks image layers without sufficient path validation mechanisms.
From an operational perspective, this vulnerability poses significant risks to containerized environments where Docker images are pulled from untrusted sources or loaded from external repositories. Attackers can leverage this weakness to execute privilege escalation attacks, modify container runtime components, or establish persistent access to host systems. The impact extends beyond individual containers to potentially compromise the entire host infrastructure, as successful exploitation can lead to full system compromise. Organizations using Docker in production environments were particularly vulnerable since many automated deployment pipelines rely on pulling images from public registries where malicious actors could inject harmful content.
The vulnerability aligns with CWE-59 and CWE-22 categories, specifically addressing improper handling of symbolic links and path traversal issues. It also maps to several ATT&CK techniques including T1059 for command and script injection, T1068 for exploit for privilege escalation, and T1566 for spearphishing with a malicious attachment. Organizations should implement immediate mitigations including updating to Docker version 1.3.2 or later, implementing image scanning for malicious content, and establishing strict policies for image source verification. Additional protective measures include running Docker containers with reduced privileges, implementing network segmentation, and monitoring for suspicious file system operations during image processing. The vulnerability underscores the importance of proper input validation and file system security in container orchestration platforms, particularly when handling untrusted data from external sources.