CVE-2023-40547: shim Memory Corruption — Fix

Description

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.

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CVSS v3.1 Score

8.3

HIGH

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

CWE-346 CWE-346

Affected Products

Vendor	Product	Versions
redhat	shim	< 15.8
redhat	enterprise_linux	All
redhat	enterprise_linux	All
redhat	enterprise_linux	All

References

Advisories & Patches

https://access.redhat.com/security/cve/CVE-2023-40547 https://bugzilla.redhat.com/show_bug.cgi?id=2234589 https://access.redhat.com/security/cve/CVE-2023-40547 https://bugzilla.redhat.com/show_bug.cgi?id=2234589

Other References

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-2024:1902 https://access.redhat.com/errata/RHSA-2024:1903 https://access.redhat.com/errata/RHSA-2024:1959 https://access.redhat.com/errata/RHSA-2024:2086 http://www.openwall.com/lists/oss-security/2024/01/26/1

Frequently Asked Questions

What is CVE-2023-40547? +

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. It has a CVSS v3.1 base score of 8.3 (HIGH).

How severe is CVE-2023-40547? +

CVE-2023-40547 has a CVSS v3.1 score of 8.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2023-40547? +

CVE-2023-40547 affects products from redhat, specifically: enterprise_linux, shim. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-40547? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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