CVE-2021-30465 : What You Need to Know
Learn about CVE-2021-30465, a vulnerability in runc before 1.0.0-rc95 allowing a Container Filesystem Breakout via Directory Traversal. Understand the impact, affected systems, exploitation, and mitigation steps.
A Container Filesystem Breakout vulnerability was found in runc before 1.0.0-rc95, allowing an attacker to exploit the vulnerability via Directory Traversal. This could be exploited by creating multiple containers with a specific mount configuration.
Understanding CVE-2021-30465
This section will provide insight into the nature and impact of CVE-2021-30465.
What is CVE-2021-30465?
CVE-2021-30465 is a vulnerability in runc before version 1.0.0-rc95 that enables a Container Filesystem Breakout through Directory Traversal. The vulnerability can be exploited by manipulating mount configurations in multiple containers.
The Impact of CVE-2021-30465
The vulnerability poses a risk of a symlink-exchange attack due to a race condition, allowing unauthorized access to file systems within containers.
Technical Details of CVE-2021-30465
This section will delve into the specifics of the vulnerability.
Vulnerability Description
The vulnerability in runc version 1.0.0-rc95 and earlier permits a symlink-exchange attack via a race condition during container creation, leading to potential filesystem exposure.
Affected Systems and Versions
All versions of runc prior to 1.0.0-rc95 are affected by this vulnerability, enabling attackers to break out of container filesystems through directory traversal.
Exploitation Mechanism
To exploit CVE-2021-30465, an attacker needs to create multiple containers with a specific mount configuration to manipulate the system through a symlink-exchange attack.
Mitigation and Prevention
This section covers the steps to mitigate the risk and secure systems against CVE-2021-30465.
Immediate Steps to Take
Users should update runc to version 1.0.0-rc95 or newer to address the vulnerability and prevent container filesystem breakouts. Implementing proper container isolation practices is also recommended.
Long-Term Security Practices
Maintaining up-to-date software versions, employing least privilege principles, and monitoring container configurations can help enhance overall system security.
Patching and Updates
Regularly check for security advisories and apply patches promptly to ensure that systems are protected against known vulnerabilities.