CVE-2021-30465
Description
The runc package is vulnerable to a symlink exchange attack whereby an attacker can request a seemingly innocuous container configuration that results in the host filesystem being bind-mounted into the container. The highest threat from this vulnerability is to data confidentiality and integrity as well as to system availability.
Security Bulletin
Statement
OpenShift Container Platform OCP 3.11 be default uses Docker from RHEL-7 extras repository. If using OCP 3.11 upgrade docker on all nodes to a fixed version from the RHEL-7 extras channel. CRI-O could be used instead of Docker on OCP 3.11 and in that case upgrade the runc version from the OCP rpm repository when it becomes available.
Mitigation
The impact of the vulnerability is reduced if SELinux is in enforcing mode using the container-selinux policy. The container-selinux policy is installed and enabled by default on RHEL 7 and 8, as well as OpenShift Container Platform 3.x and 4.x.
Customers running affected versions of RHEL are strongly recommended to apply RPM updates from the RHEL 8 channel and RHEL 7 Extras channel as soon as errata becomes available.
Customers running affected versions of OpenShift Container Platform are strongly recommended to upgrade as soon as errata becomes available.
Customers of OpenShift Online or OpenShift Dedicated have SELinux enabled in enforcing mode in every host across all clusters. Therefore, It is expected that OSO/OSD both have a reduced impact from this issue, with security patches made available during upcoming maintenance windows.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 8.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
An attacker needs permissions to run container images on a vulnerable host.
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
Acknowledgements
Red Hat would like to thank Etienne Champetier for reporting this issue.
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