CVE-2024-2312: 
Linux Debian vulnerability analysis and mitigation

GRUB2 contains a vulnerability (CVE-2024-2312) where it fails to call module fini functions on exit, causing Debian/Ubuntu's peimage GRUB2 module to leave UEFI system table hooks after exit. The vulnerability was discovered in early 2024 and affects GRUB2 implementations, particularly in Debian and Ubuntu systems. This issue creates a use-after-free condition that could potentially lead to secure boot bypass (Launchpad Bug, MITRE CVE).

The vulnerability is classified as a Use-After-Free (CWE-416) condition that occurs when GRUB2 exits without properly cleaning up module resources. Specifically, the peimage GRUB2 module leaves UEFI system table hooks active after exit, creating a potentially exploitable condition. The vulnerability has received a CVSS v3.1 Base Score of 6.7 (Medium) with the vector string CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local access requirements but high potential impact (NetApp Advisory).

The vulnerability's successful exploitation could lead to a secure boot bypass, potentially allowing unauthorized code execution in the UEFI secure boot environment. This presents significant security implications as it could compromise the system's secure boot integrity and potentially allow unauthorized modifications to the boot process (Launchpad Bug).

Fixes have been released for affected systems, including Ubuntu Noble and Mantic distributions. The fix involves reverting changes to the peimage module and increasing the SBAT level to "grub.ubuntu,2" and "grub.peimage,2". Users are advised to update their systems with the latest security patches (Launchpad Bug).