# What is CVE-2023-30549? > CVE-2023-30549 is a high-severity flaw (CVSS 7.8) in Apptainer from Lfprojects, published on 25 April 2023. 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 0.4%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2023-30549 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 46 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.8 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:** 0.4% (latest exploit-likelihood forecast) - **Published:** 25 April 2023 - **Record last updated:** 25 November 2023 - **Main product:** Apptainer from Lfprojects - **Affected products:** 3 ## What is CVE-2023-30549? In plain terms An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### The official description Apptainer is an open source container platform for Linux. There is an ext4 use-after-free flaw that is exploitable through versions of Apptainer < 1.1.0 and installations that include apptainer-suid < 1.1.8 on older operating systems where that CVE has not been patched. That includes Red Hat Enterprise Linux 7, Debian 10 buster (unless the linux-5.10 package is installed), Ubuntu 18.04 bionic and Ubuntu 20.04 focal. Use-after-free flaws in the kernel can be used to attack the kernel for denial of service and potentially for privilege escalation. Apptainer 1.1.8 includes a patch that by default disables mounting of extfs filesystem types in setuid-root mode, while continuing to allow mounting of extfs filesystems in non-setuid "rootless" mode using fuse2fs. Some workarounds are possible. Either do not install apptainer-suid (for versions 1.1.0 through 1.1.7) or set `allow setuid = no` in apptainer.conf. This requires having unprivileged user namespaces enabled and except for apptainer 1.1.x versions will disallow mounting of sif files, extfs files, and squashfs files in addition to other, less significant impacts. (Encrypted sif files are also not supported unprivileged in apptainer 1.1.x.). Alternatively, use the `limit containers` options in apptainer.conf/singularity.conf to limit sif files to trusted users, groups, and/or paths, and set `allow container extfs = no` to disallow mounting of extfs overlay files. The latter option by itself does not disallow mounting of extfs overlay partitions inside SIF files, so that's why the former options are also needed. ### What kind of flaw is it? - CWE-416: Use After Free ### How an attack on it works - Where an attacker can be: Already on the device - How hard it is to pull off: Easy: no special conditions - Login needed first: An ordinary user account - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data, change data and take it offline Severity vector: `CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` ## Is CVE-2023-30549 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 0.4%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%. ### Timeline - 25 April 2023: Published - 25 November 2023: Record last updated ### How Precursor Intelligence ranks it CVE-2023-30549 scores **46 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-2023-30549? The published record lists 3 products. Versions are as published: "before 1.1.8" means every version up to, but not including, 1.1.8. - [Apptainer](https://www.precursorintelligence.com/product/lfprojects/apptainer) by [Lfprojects](https://www.precursorintelligence.com/vendors/lfprojects) (Application): before 1.1.8 - [Enterprise Linux](https://www.precursorintelligence.com/product/redhat/enterprise_linux) by [Red Hat](https://www.precursorintelligence.com/vendors/redhat) (Operating system): 7.0 - [Singularity](https://www.precursorintelligence.com/product/sylabs/singularity) by [Sylabs](https://www.precursorintelligence.com/vendors/sylabs) (Application): all versions ## How do I fix CVE-2023-30549? 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/apptainer/apptainer/commit/5a4964f5ba9c8d89a0e353b97f51fd607670a9f7) (Patch) - [github.com](https://github.com/apptainer/apptainer/security/advisories/GHSA-j4rf-7357-f4cg) (Mitigation, Vendor advisory) - [access.redhat.com](https://access.redhat.com/security/cve/cve-2022-1184) (Not applicable) - [github.com](https://github.com/apptainer/apptainer/releases/tag/v1.1.8) (Release notes) - [github.com](https://github.com/torvalds/linux/commit/2220eaf90992c11d888fe771055d4de3303) - [github.com](https://github.com/torvalds/linux/commit/4f04351888a83e595571de672e0a4a8b74f) - [lwn.net](https://lwn.net/Articles/932136/) - [lwn.net](https://lwn.net/Articles/932137/) - [security-tracker.debian.org](https://security-tracker.debian.org/tracker/CVE-2022-1184) (Not applicable) - [security.gentoo.org](https://security.gentoo.org/glsa/202311-13) - [sylabs.io](https://sylabs.io/2023/04/response-to-cve-2023-30549/) - [ubuntu.com](https://ubuntu.com/security/CVE-2022-1184) (Not applicable) - [suse.com](https://www.suse.com/security/cve/CVE-2022-1184.html) (Not applicable) ## Questions ### What is CVE-2023-30549? CVE-2023-30549 is a high-severity flaw in Apptainer from Lfprojects, published on 25 April 2023. An attacker has to be already on the device with an ordinary user account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline. ### How serious is CVE-2023-30549? It scores 7.8 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2023-30549 is 46 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2023-30549 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 0.4%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2023-30549 affect? For Apptainer from Lfprojects: before 1.1.8. The record lists 3 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2023-30549? 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-2023-30549 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