SARA / Free Tools / CVE / CVE-2023-49721

CVE-2023-49721 — An insecure default to allow UEFI Shell in EDK2 was left enabled in LXD

An insecure default to allow UEFI Shell in EDK2 was left enabled in LXD. This allows an OS-resident attacker to bypass Secure Boot.

CVSS

6.7 MEDIUM

EPSS

0.02% (top 96.50%)

CWE

—

Published

2024-02-14T21:57:40.878Z

Last modified

2024-10-24T16:44:29.650Z

CVSS vector

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

01What is this vulnerability?

An insecure default to allow UEFI Shell in EDK2 was left enabled in LXD. This allows an OS-resident attacker to bypass Secure Boot.

Vendor	Product	Versions
Canonical Ltd.	LXD	0

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

Patch to a fixed version listed in the vendor advisory (see references below).
Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
Hunt historical logs for exploitation indicators — see Detection signatures below.

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

bugs.launchpad.net — https://bugs.launchpad.net/ubuntu/+source/lxd/+bug/2040139
nvd.nist.gov — https://nvd.nist.gov/vuln/detail/CVE-2023-48733
www.openwall.com — https://www.openwall.com/lists/oss-security/2024/02/14/4
bugs.launchpad.net — https://bugs.launchpad.net/ubuntu/+source/edk2/+bug/2040137

Want this in your SOAR or SIEM?
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