runc is a CLI tool for spawning and running containers according to the OCI specification. runc 1.1.13 and earlier, as well as 1.2.0-rc2 and earlier, can be tricked into creating empty files or directories in arbitrary locations in the host filesystem by sharing a volume between two containers and exploiting a race with `os.MkdirAll`. While this could be used to create empty files, existing files would not be truncated. An attacker must have the ability to start containers using some kind of custom volume configuration. Containers using user namespaces are still affected, but the scope of places an attacker can create inodes can be significantly reduced. Sufficiently strict LSM policies (SELinux/Apparmor) can also in principle block this attack -- we suspect the industry standard SELinux policy may restrict this attack's scope but the exact scope of protection hasn't been analysed. This is exploitable using runc directly as well as through Docker and Kubernetes. The issue is fixed in runc v1.1.14 and v1.2.0-rc3. Some workarounds are available. Using user namespaces restricts this attack fairly significantly such that the attacker can only create inodes in directories that the remapped root user/group has write access to. Unless the root user is remapped to an actual user on the host (such as with rootless containers that don't use `/etc/sub[ug]id`), this in practice means that an attacker would only be able to create inodes in world-writable directories. A strict enough SELinux or AppArmor policy could in principle also restrict the scope if a specific label is applied to the runc runtime, though neither the extent to which the standard existing policies block this attack nor what exact policies are needed to sufficiently restrict this attack have been thoroughly tested.
History

Tue, 03 Sep 2024 20:30:00 +0000

Type Values Removed Values Added
References

Tue, 03 Sep 2024 19:15:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE. runc is a CLI tool for spawning and running containers according to the OCI specification. runc 1.1.13 and earlier, as well as 1.2.0-rc2 and earlier, can be tricked into creating empty files or directories in arbitrary locations in the host filesystem by sharing a volume between two containers and exploiting a race with `os.MkdirAll`. While this could be used to create empty files, existing files would not be truncated. An attacker must have the ability to start containers using some kind of custom volume configuration. Containers using user namespaces are still affected, but the scope of places an attacker can create inodes can be significantly reduced. Sufficiently strict LSM policies (SELinux/Apparmor) can also in principle block this attack -- we suspect the industry standard SELinux policy may restrict this attack's scope but the exact scope of protection hasn't been analysed. This is exploitable using runc directly as well as through Docker and Kubernetes. The issue is fixed in runc v1.1.14 and v1.2.0-rc3. Some workarounds are available. Using user namespaces restricts this attack fairly significantly such that the attacker can only create inodes in directories that the remapped root user/group has write access to. Unless the root user is remapped to an actual user on the host (such as with rootless containers that don't use `/etc/sub[ug]id`), this in practice means that an attacker would only be able to create inodes in world-writable directories. A strict enough SELinux or AppArmor policy could in principle also restrict the scope if a specific label is applied to the runc runtime, though neither the extent to which the standard existing policies block this attack nor what exact policies are needed to sufficiently restrict this attack have been thoroughly tested.
Title runc: runc can be tricked into creating empty files/directories on host runc can be confused to create empty files/directories on the host
Weaknesses CWE-363
CWE-61
References

Tue, 03 Sep 2024 13:15:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE.
Title runc: runc can be tricked into creating empty files/directories on host
Weaknesses CWE-22
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.6, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N'}

threat_severity

Low


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2024-09-03T19:07:34.060Z

Updated: 2024-09-03T20:03:57.256Z

Reserved: 2024-08-26T18:25:35.444Z

Link: CVE-2024-45310

cve-icon Vulnrichment

Updated: 2024-09-03T20:03:16.275Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2024-09-03T19:15:15.243

Modified: 2024-09-03T19:40:46.783

Link: CVE-2024-45310

cve-icon Redhat

Severity : Low

Publid Date: 2024-09-03T11:17:32Z

Links: CVE-2024-45310 - Bugzilla