RHSA-2024:2086 - Security Advisory

Topic

An update for shim is now available for Red Hat Enterprise Linux 8.6 Extended
Update Support.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The shim package contains a first-stage UEFI boot loader that handles chaining
to a trusted full boot loader under secure boot environments.

Security Fix(es):

• shim: RCE in http boot support may lead to Secure Boot bypass (CVE-2023-40547)
• shim: Interger overflow leads to heap buffer overflow in verify_sbat_section

on 32-bits systems (CVE-2023-40548)

• shim: Out-of-bounds read printing error messages (CVE-2023-40546)
• shim: Out-of-bounds read in verify_buffer_authenticode() malformed PE file

(CVE-2023-40549)

• shim: Out-of-bound read in verify_buffer_sbat() (CVE-2023-40550)
• shim: out of bounds read when parsing MZ binaries (CVE-2023-40551)

For more details about the security issue(s), including the impact, a CVSS
score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Update Support 8.6 x86_64
• Red Hat Enterprise Linux Server - AUS 8.6 x86_64
• Red Hat Enterprise Linux Server - TUS 8.6 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Update Support 8.6 aarch64
• Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 8.6 x86_64

Fixes

• BZ - 2234589 - CVE-2023-40547 shim: RCE in http boot support may lead to Secure Boot bypass
• BZ - 2241782 - CVE-2023-40548 shim: Interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems
• BZ - 2241796 - CVE-2023-40546 shim: Out-of-bounds read printing error messages
• BZ - 2241797 - CVE-2023-40549 shim: Out-of-bounds read in verify_buffer_authenticode() malformed PE file
• BZ - 2259915 - CVE-2023-40550 shim: Out-of-bound read in verify_buffer_sbat()
• BZ - 2259918 - CVE-2023-40551 shim: out of bounds read when parsing MZ binaries

CVEs

• CVE-2023-40546
• CVE-2023-40547
• CVE-2023-40548
• CVE-2023-40549
• CVE-2023-40550
• CVE-2023-40551

References

• https://access.redhat.com/security/updates/classification/#important