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CVE-2023-4693

Published: 3 October 2023

An out-of-bounds read flaw was found on grub2's NTFS filesystem driver. This issue may allow a physically present attacker to present a specially crafted NTFS file system image to read arbitrary memory locations. A successful attack allows sensitive data cached in memory or EFI variable values to be leaked, presenting a high Confidentiality risk.

From the Ubuntu Security Team

It was discovered that a specially crafted file system image could cause an out-of-bounds read. A local attacker could possibly use this to leak sensitive information to the GRUB pager.

Notes

AuthorNote
eslerm
grub2-unsigned contains Secure Boot security fixes
the grub2 package unlikely affects Ubuntu's Secure Boot
grub2 and grub2-unsigned should have same major version
eslerm
Ubuntu Secure Boot and ESM do not cover i386 trusty's GA kernel cannot handle new versions of grub Note that key revocation is required to protect against evil housekeeper attacks (such as BlackLotus)
eslerm
CWE-125

Priority

Medium

Cvss 3 Severity Score

4.6

Score breakdown

Status

Package Release Status
grub2
Launchpad, Ubuntu, Debian
bionic Not vulnerable
(does not affect Secure Boot)
focal Not vulnerable
(does not affect Secure Boot)
lunar Ignored
(end of life, was needs-triage)
upstream
Released (2.12~rc1-11)
mantic Not vulnerable
(does not affect Secure Boot)
jammy Not vulnerable
(does not affect Secure Boot)
trusty Not vulnerable
(does not affect Secure Boot)
xenial Not vulnerable
(does not affect Secure Boot)
grub2-unsigned
Launchpad, Ubuntu, Debian
trusty Ignored
(end of standard support)
xenial Needs triage

bionic Needs triage

upstream Needs triage

focal
Released (2.06-2ubuntu14.4)
jammy
Released (2.06-2ubuntu14.4)
lunar
Released (2.06-2ubuntu17.2)
mantic Not vulnerable
(2.12~rc1-10ubuntu4)
grub2-signed
Launchpad, Ubuntu, Debian
trusty Ignored
(update incompatible with kernel)
xenial Needs triage

bionic Needs triage

upstream Needs triage

focal
Released (1.187.6~20.04.1)
jammy
Released (1.187.6)
lunar
Released (1.193.2)
mantic
Released (1.197)

Severity score breakdown

Parameter Value
Base score 4.6
Attack vector Physical
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact None
Availability impact None
Vector CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N