CVE-2020-15229 Information

Description

Singularity (an open source container platform) from version 3.1.1 through 3.6.3 has a vulnerability. Due to insecure handling of path traversal and the lack of path sanitization within unsquashfs it is possible to overwrite/create any files on the host filesystem during the extraction with a crafted squashfs filesystem. The extraction occurs automatically for unprivileged (either installation or with allow setuid = no) run of Singularity when a user attempt to run an image which is a local SIF image or a single file containing a squashfs filesystem and is coming from remote sources library:// or shub://. Image build is also impacted in a more serious way as it can be used by a root user allowing an attacker to overwrite/create files leading to a system compromise so far bootstrap methods library shub and localimage are triggering the squashfs extraction. This issue is addressed in Singularity 3.6.4. All users are advised to upgrade to 3.6.4 especially if they use Singularity mainly for building image as root user. There is no solid workaround except to temporary avoid to use unprivileged mode with single file images in favor of sandbox images instead. Regarding image build temporary avoid to build from library and shub sources and as much as possible use --fakeroot or a VM for that.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

Reference

http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00070.html http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00071.html http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00009.html https://github.com/hpcng/singularity/blob/v3.6.4/CHANGELOG.mdsecurity-related-fixes https://github.com/hpcng/singularity/commit/eba3dea260b117198fdb6faf41f2482ab2f8d53e https://github.com/hpcng/singularity/pull/5611 https://github.com/hpcng/singularity/security/advisories/GHSA-7gcp-w6ww-2xv9

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

NONE

Base Severity

9.3