# What is CVE-2020-15229? > CVE-2020-15229 is a critical-severity flaw (CVSS 9.3) in Singularity from Sylabs, published on 14 October 2020. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 2.0%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2020-15229 ## At a glance - **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. - **Precursor Intelligence risk score:** 54 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Critical (CVSS 9.3 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 2.0% (latest exploit-likelihood forecast) - **Published:** 14 October 2020 - **Record last updated:** 16 November 2022 - **Main product:** Singularity from Sylabs - **Affected products:** 3 ## What is CVE-2020-15229? In plain terms It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can read data and change data. ### The 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. ### What kind of flaw is it? - CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: Yes, a person has to take an action - What an attacker gets: Can read data and change data Severity vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N` ## Is CVE-2020-15229 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 2.0%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%. ### Timeline - 14 October 2020: Published - 16 November 2022: Record last updated ### How Precursor Intelligence ranks it CVE-2020-15229 scores **54 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2020-15229? The published record lists 3 products. - [Singularity](https://www.precursorintelligence.com/product/sylabs/singularity) by [Sylabs](https://www.precursorintelligence.com/vendors/sylabs) (Application): 3.1.1 to 3.6.3 - [Leap](https://www.precursorintelligence.com/product/opensuse/leap) by [Opensuse](https://www.precursorintelligence.com/vendors/opensuse) (Operating system): 15.1, 15.2 - [Backports Sle](https://www.precursorintelligence.com/product/opensuse/backports_sle) by [Opensuse](https://www.precursorintelligence.com/vendors/opensuse) (Application): 15.0-sp2 ## How do I fix CVE-2020-15229? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [github.com](https://github.com/hpcng/singularity/commit/eba3dea260b117198fdb6faf41f2482ab2f8d53e) (Patch, Third-party advisory) - [github.com](https://github.com/hpcng/singularity/pull/5611) (Patch, Third-party advisory) - [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00070.html) (Broken link, Mailing list, Third-party advisory) - [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00071.html) (Broken link, Mailing list, Third-party advisory) - [lists.opensuse.org](http://lists.opensuse.org/opensuse-security-announce/2020-11/msg00009.html) (Broken link, Mailing list, Third-party advisory) - [github.com](https://github.com/hpcng/singularity/blob/v3.6.4/CHANGELOG.md#security-related-fixes) (Release notes, Third-party advisory) - [github.com](https://github.com/hpcng/singularity/security/advisories/GHSA-7gcp-w6ww-2xv9) (Third-party advisory) ## Questions ### What is CVE-2020-15229? CVE-2020-15229 is a critical-severity flaw in Singularity from Sylabs, published on 14 October 2020. It can be attacked from anywhere on the internet without logging in, but a person has to take an action first. If it works, the attacker can read data and change data. ### How serious is CVE-2020-15229? It scores 9.3 out of 10 on the CVSS severity scale, which is critical. Our risk score for CVE-2020-15229 is 54 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month. ### Is CVE-2020-15229 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 2.0%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2020-15229 affect? For Singularity from Sylabs: 3.1.1 to 3.6.3. The record lists 3 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2020-15229? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2020-15229 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact