Vulnerability · Published Oct 14, 2020 · Assigned by GitHub_M
CVE-2020-15229Path traversal and files overwrite with unsquashfs
High 8.2
In plain English
A high-severity path traversal in singularity from hpcng. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.0% (higher than 81% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | singularity | 3.6.4-r0 | ALPINE-CVE-2020-15229 |
| Alpine:v3.21 | singularity | 3.6.4-r0 | ALPINE-CVE-2020-15229 |
| Alpine:v3.22 | singularity | 3.6.4-r0 | ALPINE-CVE-2020-15229 |
| Alpine:v3.23 | singularity | 3.6.4-r0 | ALPINE-CVE-2020-15229 |
| Alpine:v3.24 | singularity | 3.6.4-r0 | ALPINE-CVE-2020-15229 |
| Go | github.com/sylabs/singularity | 3.6.4 | GHSA-7gcp-w6ww-2xv9 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| hpcng | singularity | < 3.6.4 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
References
- https://github.com/hpcng/singularity/security/advisories/GHSA-7gcp-w6ww-2xv9 x_refsource_CONFIRM
- https://github.com/hpcng/singularity/blob/v3.6.4/CHANGELOG.md#security-related-fixes x_refsource_MISC
- https://github.com/hpcng/singularity/pull/5611 x_refsource_MISC
- https://github.com/hpcng/singularity/commit/eba3dea260b117198fdb6faf41f2482ab2f8d53e x_refsource_MISC
- openSUSE-SU-2020:1769 vendor-advisory, x_refsource_SUSE
- openSUSE-SU-2020:1770 vendor-advisory, x_refsource_SUSE
- openSUSE-SU-2020:1814 vendor-advisory, x_refsource_SUSE