CVE-2023-40547: Shim: rce in http boot support may lead to secure boot bypass
First published: Thu Aug 24 2023(Updated: )
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.
Credit: secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Red Hat Shim | =15.8 | |
| Microsoft Windows Server 2012 R2 | ||
| Microsoft Windows Server 2012 R2 | ||
| Microsoft Windows Server 2022 23H2 | ||
| Red Hat Shim | <15.8 | |
| Red Hat Enterprise Linux | =7.0 | |
| Red Hat Enterprise Linux | =8.0 | |
| Red Hat Enterprise Linux | =9.0 | |
| Microsoft Windows Server | ||
| Microsoft Windows Server | ||
| Microsoft Windows Server 2019 | ||
| Microsoft Windows Server 2019 | ||
| Windows 11 | =23H2 | |
| Windows 11 | =22H2 | |
| Windows 11 | =22H2 | |
| Windows 11 | =24H2 | |
| Windows 11 | =24H2 | |
| Windows 11 | =21H2 | |
| Windows 11 | =21H2 | |
| Windows 11 | =23H2 | |
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2022 | ||
| Microsoft Windows Server 2016 | ||
| Microsoft Windows Server 2016 | ||
| redhat/shim | <15.8 | 15.8 |
| Windows 10 | =1809 | |
| Windows 10 | =1809 | |
| Windows 10 | =1809 | |
| Windows 10 | =22H2 | |
| Windows 10 | =22H2 | |
| Windows 10 | =22H2 | |
| Windows 10 | =1607 | |
| Windows 10 | =1607 | |
| Windows 10 | =21H2 | |
| Windows 10 | =21H2 | |
| Windows 10 | =21H2 | |
| Windows 10 | ||
| Windows 10 |
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Reference Links
- https://www.bleepingcomputer.com/news/security/critical-flaw-in-shim-bootloader-impacts-major-linux-distros/
- https://www.zdnet.com/article/shim-vulnerability-exposes-most-linux-systems-to-attack/
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-40547 (Advisory)
- https://github.com/rhboot/shim
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2259914
- https://access.redhat.com/errata/RHSA-2024:1834
- https://access.redhat.com/errata/RHSA-2024:1835
- https://access.redhat.com/errata/RHSA-2024:1873
- https://access.redhat.com/errata/RHSA-2024:1876
- https://access.redhat.com/errata/RHSA-2024:1883
- https://access.redhat.com/errata/RHSA-2024:1903
- https://access.redhat.com/errata/RHSA-2024:1902
- https://access.redhat.com/errata/RHSA-2024:1959
- https://access.redhat.com/errata/RHSA-2024:2086
- https://bugzilla.redhat.com/show_bug.cgi?id=2234589
- https://access.redhat.com/security/cve/CVE-2023-40547
Frequently Asked Questions
What is the severity of CVE-2023-40547?
CVE-2023-40547 is classified as a critical vulnerability due to its potential for remote code execution.
How do I fix CVE-2023-40547?
To fix CVE-2023-40547, apply the appropriate security patches provided by your vendor.
What products are affected by CVE-2023-40547?
CVE-2023-40547 affects various versions of Red Hat Shim and multiple Windows operating systems.
What are the consequences of exploiting CVE-2023-40547?
Exploiting CVE-2023-40547 can lead to complete control of the affected system through out-of-bounds writes.
Is CVE-2023-40547 under active exploitation?
There have been reports indicating that CVE-2023-40547 may be actively exploited in the wild.
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