Security restrictions bypass in containerd - CVE-2021-43816
Published: January 6, 2022
Vulnerability identifier: #VU59237
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-43816
CWE-ID: CWE-264
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: containerd
Affected software:
containerd
containerd
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a logic issue, which causes arbitrary files and directories on the host to be relabeled to match the container process label through the use of specially-configured bind mounts in a hostPath volume. A local user can place the in-container location of the hostPath volume mount at either `/etc/hosts`, `/etc/hostname`, or `/etc/resolv.conf` and gain read/write access to arbitrary file on the system.
The vulnerability affects containerd installations using SELinux, such as EL8 (CentOS, RHEL), Fedora, or SUSE MicroOS.
How to mitigate CVE-2021-43816
Install updates from vendor's website.