CVE-2021-41089 : Exploit Details and Defense Strategies

Moby (Docker Engine) prior to version 20.10.9 is vulnerable to a bug that can lead to unexpected Unix file permission changes. Find out the impact, technical details, and mitigation steps related to CVE-2021-41089.

Understanding CVE-2021-41089

The vulnerability in Moby (Docker Engine) can result in widened access to host filesystem files through

docker cp

, potentially impacting confidentiality and integrity.

What is CVE-2021-41089?

A bug in Moby (Docker Engine) that allows unauthorized file permission changes when copying files into a crafted container
This bug does not directly permit reading, modifying, or executing files without additional processes

The Impact of CVE-2021-41089

Base Score: 2.8 (Low Severity)
Attack Vector: Local
Privileges Required: Low
Scope: Changed (Impact limited to host file permissions)

Technical Details of CVE-2021-41089

This section covers the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

Improper handling by

docker cp

in Moby may alter host file permissions

Affected Systems and Versions

Moby (Docker Engine) versions prior to 20.10.9

Exploitation Mechanism

Copying files using

docker cp

into a modified container triggers permission changes on host files

Mitigation and Prevention

Learn how to address the CVE-2021-41089 vulnerability and prevent potential security issues.

Immediate Steps to Take

Update Moby (Docker Engine) to version 20.10.9 to mitigate the vulnerability
Regularly monitor and review file permissions in the host filesystem

Long-Term Security Practices

Implement least privilege principles for container interactions
Conduct regular security assessments and audits to identify such vulnerabilities

Patching and Updates

Stay informed about security advisories and promptly apply patches to mitigate similar risks