This vulnerability allows cache poisoning in Moby, an open-source project created by Docker for software containerization. The classic builder cache system is susceptible when an image is built FROM scratch, with certain instructions, such as HEALTHCHECK and ONBUILD, not causing a cache miss. An attacker aware of the Dockerfile in use could exploit this by making a user pull a specially crafted image considered a valid cache candidate for some build steps.
As a result, users of versions 23.0+ are only affected if they have opted out of Buildkit by setting the DOCKER_BUILDKIT=0 environment variable or are utilizing the /build API endpoint. All users on versions older than 23.0 are at risk. The image build API endpoint (/build) and the ImageBuild function from github.com/docker/docker/client are also affected, as they use the classic builder by default.
Patches addressing this vulnerability are included in the 24.0.9 and 25.0.2 releases. Organizations should prioritize patching immediately.
The exploitation status is currently classified as medium, with no known exploits available. However, the potential for cache poisoning presents a significant risk to organizations using affected versions.
Vulnerability Details
The Moby cache poisoning vulnerability is classified as a medium severity issue with a CVSS score of 6.9. The vulnerability arises when the classic builder cache system fails to properly handle certain instructions, leading to the possibility of an attacker manipulating the build cache. The affected product is Moby, developed by Mobyproject, with a publication date of February 1, 2024.
Technical Analysis
The root cause of this vulnerability is the classic builder cache system's inability to invalidate the cache properly when certain Dockerfile instructions are updated. The attack vector is local, requiring the attacker to have access to the system where the Docker build process is executed. The attack complexity is rated as high, meaning that it requires specific knowledge of the Dockerfile and the ability to craft a malicious image.
Privileges required are none, but user interaction is required to trigger the cache poisoning by pulling the malicious image. The confidentiality impact is low, while the integrity impact is high due to the potential for malicious images to affect the build process. Availability impact is low as the cache poisoning does not prevent the system from functioning but could lead to unintended behavior.
Risk & Impact Analysis
Risk to organizations includes the potential for compromised builds that could introduce vulnerabilities into production environments. The blast radius could be significant, especially for organizations relying heavily on containerization and automated build processes. Given the CVSS score of 6.9, organizations should address this vulnerability in their priority patch cycle.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
Versions of Moby prior to 24.0.9 and 25.0.2 are affected by this vulnerability. Users should upgrade to these versions or above to mitigate the risks associated with this issue.
Mitigation & Remediation
Patching is the primary method to remediate this vulnerability. Users should update to the latest versions of Moby, specifically 24.0.9 or 25.0.2. For those unable to upgrade immediately, they should consider workarounds such as disabling the classic builder or limiting access to the build API endpoint.
Organizations should validate remediation effectiveness through penetration testing to ensure similar vulnerabilities do not exist.
Detection Guidance
Organizations should monitor logs for indicators of cache manipulation attempts and unusual image pulls. Behavioral anomalies during the image build process could signify an exploitation attempt. Additionally, network signatures related to unauthorized access to the build API should be scrutinized.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability lies in the importance of secure container management practices. Security teams should recognize the patterns of misconfiguration leading to vulnerabilities like this and implement robust testing protocols. Organizations are encouraged to adopt a comprehensive penetration testing methodology to enhance their defenses against similar threats.
Furthermore, organizations should consider integrating continuous security practices into their development lifecycle. For more information on how to secure your development pipeline, refer to our vulnerability management program design guidance.
Finally, organizations should stay informed about emerging vulnerabilities and security trends, particularly in containerization technologies, to maintain a proactive security posture.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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