CVE-2021-43784 : Exploit Details and Defense Strategies
Discover how CVE-2021-43784 impacts runc container runtime. Learn about the vulnerability in netlink byte message length field allowing attackers to bypass namespace protections.
A vulnerability in netlink byte message length field in runc container runtime allows attackers to override container configuration, impacting versions prior to 1.0.3.
Understanding CVE-2021-43784
CVE-2021-43784 is a vulnerability in runc container runtime that could lead to an attacker bypassing namespace restrictions by manipulating container configurations.
What is CVE-2021-43784?
runc, a CLI tool for managing containers according to OCI specs, is susceptible to an integer overflow in the netlink byte message length field prior to version 1.0.3. This can enable attackers to compromise container namespaces.
The Impact of CVE-2021-43784
The vulnerability poses a medium severity risk with a CVSS score of 6. Attackers could exploit this to control container configurations and potentially disable namespace protections.
Technical Details of CVE-2021-43784
This section provides detailed technical insights into the vulnerability.
Vulnerability Description
In runc versions before 1.0.3, an integer overflow in the netlink byte message length field could allow attackers to parse attribute contents as netlink messages, potentially overriding container configurations.
Affected Systems and Versions
- Product: runc
- Vendor: opencontainers
- Versions affected: < 1.0.3
Exploitation Mechanism
Attackers with control over the container configuration could add a malicious netlink payload, disabling all namespaces and bypassing container restrictions.
Mitigation and Prevention
Effective mitigation strategies and preventative measures.
Immediate Steps to Take
- Update runc to version 1.0.3 or later to patch the vulnerability.
- Disallow untrusted namespace paths from containers as a temporary workaround.
Long-Term Security Practices
- Regularly update container runtime tools to the latest versions.
- Implement container security best practices to minimize exposure to vulnerabilities.
Patching and Updates
Ensure timely application of security patches for container runtimes.