Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
High
Attack Vector
Network
0

CVE-2021-43816

Disclosure Date: January 05, 2022 •
CVE-2021-43816 CVSS v3 Base Score: 9.1
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

containerd is an open source container runtime. On installations using SELinux, such as EL8 (CentOS, RHEL), Fedora, or SUSE MicroOS, with containerd since v1.5.0-beta.0 as the backing container runtime interface (CRI), an unprivileged pod scheduled to the node may bind mount, via hostPath volume, any privileged, regular file on disk for complete read/write access (sans delete). Such is achieved by placing the in-container location of the hostPath volume mount at either /etc/hosts, /etc/hostname, or /etc/resolv.conf. These locations are being relabeled indiscriminately to match the container process-label which effectively elevates permissions for savvy containers that would not normally be able to access privileged host files. This issue has been resolved in version 1.5.9. Users are advised to upgrade as soon as possible.

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CVSS V3 Severity and Metrics
Base Score:
9.1 Critical
Impact Score:
6
Exploitability Score:
2.3
Vector:
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
High
User Interaction (UI):
None
Scope (S):
Changed
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Offensive Application
Unknown
Utility Class
Unknown
Ports
Unknown
OS
Unknown
Vulnerable Versions
containerd >= 1.5.0, < 1.5.9
Prerequisites
Unknown
Discovered By
Unknown
PoC Author
Unknown
Metasploit Module
Unknown
Reporter
Unknown

Vendors

  • fedoraproject,
  • linuxfoundation

Products

  • containerd,
  • containerd 1.5.0,
  • fedora 34,
  • fedora 35
Technical Analysis