Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Physical
0

CVE-2023-39950

Disclosure Date: August 14, 2023
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

efibootguard is a simple UEFI boot loader with support for safely switching between current and updated partition sets. Insufficient or missing validation and sanitization of input from untrustworthy bootloader environment files can cause crashes and probably also code injections into bg_setenv) or programs using libebgenv. This is triggered when the affected components try to modify a manipulated environment, in particular its user variables. Furthermore, bg_printenv may crash over invalid read accesses or report invalid results. Not affected by this issue is EFI Boot Guard’s bootloader EFI binary. EFI Boot Guard release v0.15 contains required patches to sanitize and validate the bootloader environment prior to processing it in userspace. Its library and tools should be updated, so should programs statically linked against it. An update of the bootloader EFI executable is not required. The only way to prevent the issue with an unpatched EFI Boot Guard version is to avoid accesses to user variables, specifically modifications to them.

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CVSS V3 Severity and Metrics
Base Score:
5.2 Medium
Impact Score:
4.2
Exploitability Score:
0.9
Vector:
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Attack Vector (AV):
Physical
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
High
Availability (A):
Low

General Information

Vendors

  • siemens

Products

  • efibootguard
Technical Analysis