Bug 2023448 (CVE-2021-41091)

Summary: CVE-2021-41091 moby: data directory contains subdirectories with insufficiently restricted permissions, which could lead to directory traversal
Product: [Other] Security Response Reporter: Michael Kaplan <mkaplan>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: alazar, amurdaca, aos-bugs, aos-install, bdettelb, bmontgom, caswilli, cnv-qe-bugs, crarobin, dwalsh, eparis, fdeutsch, fdupont, fjansen, gghezzo, gparvin, jburrell, jhrozek, jmadigan, jramanat, kaycoth, lgamliel, mfilanov, mrogers, ngough, nstielau, pahickey, pamccart, pdhamdhe, rfreiman, sponnaga, stcannon, team-winc, vkumar, xiyuan
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: moby 20.10.9 Doc Type: If docs needed, set a value
Doc Text:
A file permissions vulnerability was found in the Moby (Docker Engine). The Moby data directory (usually /var/lib/docker) contains subdirectories with insufficiently restricted permissions, allowing unprivileged Linux users to traverse directory contents and execute programs. When the running container contains executable programs with the extended permission bits (like setuid), unprivileged Linux users can discover and execute those programs. Additionally, when the UID of an unprivileged Linux user on the host collides with the file owner or group inside a container, the unprivileged Linux user on the host can discover, read, and modify those files. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2022-03-03 19:32:54 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2010238, 2010241, 2023965, 2023966, 2023967, 2023968, 2023969, 2024828, 2024830, 2026050, 2026051, 2026052, 2026053, 2026054, 2026055, 2026056, 2026057    
Bug Blocks: 2023450    

Description Michael Kaplan 2021-11-15 18:06:12 UTC 
A bug was found in Moby (Docker Engine) where the data directory (typically `/var/lib/docker`) contained subdirectories with insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as `setuid`), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. 

References: 

https://github.com/moby/moby/commit/f0ab919f518c47240ea0e72d0999576bb8008e64
https://github.com/moby/moby/security/advisories/GHSA-3fwx-pjgw-3558
Comment 8 errata-xmlrpc 2022-03-03 06:58:03 UTC 
This issue has been addressed in the following products:

  Red Hat Advanced Cluster Management for Kubernetes 2.4 for RHEL 8

Via RHSA-2022:0735 https://access.redhat.com/errata/RHSA-2022:0735
Comment 9 Product Security DevOps Team 2022-03-03 19:32:51 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-41091