What is CVE-2021-32635?A medium-severity flaw in Singularity, explained.
CVE-2021-32635 is a medium-severity flaw (CVSS 6.3) in Singularity from Sylabs, published on 28 May 2021. 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 1.4%. If you run an affected version, plan in the vendor’s fix.
Published 28 May 2021. Record last updated 22 April 2022. We keep this page's data up to date.
What is CVE-2021-32635? 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 some data, change some data and slow it down.
Singularity is an open source container platform. In verions 3.7.2 and 3.7.3, Dde to incorrect use of a default URL, `singularity` action commands (`run`/`shell`/`exec`) specifying a container using a `library://` URI will always attempt to retrieve the container from the default remote endpoint (`cloud.sylabs.io`) rather than the configured remote endpoint. An attacker may be able to push a malicious container to the default remote endpoint with a URI that is identical to the URI used by a victim with a non-default remote endpoint, thus executing the malicious container. Only action commands (`run`/`shell`/`exec`) against `library://` URIs are affected. Other commands such as `pull` / `push` respect the configured remote endpoint. The vulnerability is patched in Singularity version 3.7.4. Two possible workarounds exist: Users can only interact with the default remote endpoint, or an installation can have an execution control list configured to restrict execution to containers signed with specific secure keys.
What kind of flaw is it?
- CWE-20Improper Input Validation
- CWE-923Improper Restriction of Communication Channel to Intended Endpoints
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAnywhere on the internet
- How hard it is to pull offEasy: no special conditions
- Login needed firstNo login needed
- Does someone have to clickYes, a person has to take an action
- What an attacker getsCan read some data, change some data and slow it down
Severity vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
Is CVE-2021-32635 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 1.4%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Record last updated
CVE-2021-32635 scores 25. Action: Monitor.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2021-32635 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2021-32635? One product.
The published record lists 1 product from 1 vendor. If you run one of these, check your version, then go to the fix below.
- Application
Singularity
by Sylabs
Affected versions3.7.23.7.3
How do I fix CVE-2021-32635? Four steps.
- Check whether you run itCompare 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.
- Apply the vendor’s fixInstall the latest update from the vendor. The references list where the vendor has published details.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack 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.
Does CVE-2021-32635 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
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1 new flaw affects software Acme tracks
Singularity is an open source container platform. In verions 3.7.2 and 3.7.3, Dde to incorrect use of a default URL, `singularity` action commands (`run`/`sh...
- Matched to
- Singularity on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2021-32635 is a medium-severity flaw in Singularity from Sylabs, published on 28 May 2021. 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 some data, change some data and slow it down.
It scores 6.3 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2021-32635 is 25 out of 100, which is Low. Its action is "Monitor". No sign of exploitation and a low forecast. Patch it in your normal update cycle.
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 1.4%. That can change at any time, which is why we keep watching.
For Singularity from Sylabs: 3.7.2, 3.7.3.
Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.