CVE-2023-40547
Published: 23 January 2024
A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise. This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the-Middle or compromise the boot server to be able to exploit this vulnerability successfully.
Notes
| Author | Note |
|---|---|
| eslerm | UEFI Security Response Team states that dbx update is not needed secureboot-db should only ever be updated after shim secureboot-db is not updated on ESM releases as doing so would revoke install media keys Note that key revocation is required to protect against evil housekeeper attacks (such as BlackLotus) |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
secureboot-db Launchpad, Ubuntu, Debian |
bionic |
Not vulnerable
(sbat only update)
|
| focal |
Not vulnerable
(sbat only update)
|
|
| jammy |
Not vulnerable
(sbat only update)
|
|
| lunar |
Ignored
(end of life, was needs-triage)
|
|
| mantic |
Not vulnerable
(sbat only update)
|
|
| noble |
Not vulnerable
(sbat only update)
|
|
| trusty |
Not vulnerable
(sbat only update)
|
|
| upstream |
Not vulnerable
(sbat only update)
|
|
| xenial |
Not vulnerable
(sbat only update)
|
|
|
shim Launchpad, Ubuntu, Debian |
bionic |
Needs triage
|
| focal |
Needed
|
|
| jammy |
Needed
|
|
| lunar |
Ignored
(end of life, was needs-triage)
|
|
| mantic |
Needed
|
|
| noble |
Released
(15.8-0ubuntu1)
|
|
| trusty |
Ignored
(install media keys will never be revoked)
|
|
| upstream |
Needs triage
|
|
| xenial |
Ignored
(install media keys will never be revoked)
|
|
|
Patches: upstream: https://github.com/rhboot/shim/commit/0226b56513b2b8bd5fd281bce77c40c9bf07c66d |
||
|
shim-signed Launchpad, Ubuntu, Debian |
bionic |
Needs triage
|
| focal |
Needed
|
|
| jammy |
Needed
|
|
| lunar |
Ignored
(end of life, was needs-triage)
|
|
| mantic |
Needed
|
|
| noble |
Released
(15.8)
|
|
| trusty |
Ignored
(install media keys will never be revoked)
|
|
| upstream |
Needs triage
|
|
| xenial |
Ignored
(install media keys will never be revoked)
|
|
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.0 |
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Changed |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |