shim-unsigned-x64-15.4-4.el8.ML.2

エラータID: AXSA:2021-2174:02

Release date: 
Thursday, July 8, 2021 - 10:37
Subject: 
shim-unsigned-x64-15.4-4.el8.ML.2
Affected Channels: 
Asianux Server 8 for x86_64
Severity: 
Moderate
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):

* grub2: acpi command allows privileged user to load crafted ACPI tables when Secure Boot is enabled (CVE-2020-14372)
* grub2: Use-after-free in rmmod command (CVE-2020-25632)
* grub2: Out-of-bounds write in grub_usb_device_initialize() (CVE-2020-25647)
* grub2: Stack buffer overflow in grub_parser_split_cmdline() (CVE-2020-27749)
* grub2: cutmem command allows privileged user to remove memory regions when Secure Boot is enabled (CVE-2020-27779)
* grub2: Heap out-of-bounds write in short form option parser (CVE-2021-20225)
* grub2: Heap out-of-bounds write due to miscalculation of space required for quoting (CVE-2021-20233)

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.

CVE-2020-14372
A flaw was found in grub2 in versions prior to 2.06, where it incorrectly enables the usage of the ACPI command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable content directly into memory. The table is further loaded and executed by the kernel, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code. The highest threat from this vulnerability is to data confidentiality and integrity, as well as system availability.
CVE-2020-25632
A flaw was found in grub2 in versions prior to 2.06. The rmmod implementation allows the unloading of a module used as a dependency without checking if any other dependent module is still loaded leading to a use-after-free scenario. This could allow arbitrary code to be executed or a bypass of Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2020-25647
A flaw was found in grub2 in versions prior to 2.06. During USB device initialization, descriptors are read with very little bounds checking and assumes the USB device is providing sane values. If properly exploited, an attacker could trigger memory corruption leading to arbitrary code execution allowing a bypass of the Secure Boot mechanism. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2020-27749
A flaw was found in grub2 in versions prior to 2.06. Variable names present are expanded in the supplied command line into their corresponding variable contents, using a 1kB stack buffer for temporary storage, without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution which could also circumvent Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2020-27779
A flaw was found in grub2 in versions prior to 2.06. The cutmem command does not honor secure boot locking allowing an privileged attacker to remove address ranges from memory creating an opportunity to circumvent SecureBoot protections after proper triage about grub's memory layout. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2021-20225
A flaw was found in grub2 in versions prior to 2.06. The option parser allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVE-2021-20233
A flaw was found in grub2 in versions prior to 2.06. Setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters which allows an attacker to corrupt memory by one byte for each quote in the input. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Solution: 

Update packages.

Additional Info: 

N/A

Download: 

SRPMS
  1. shim-unsigned-x64-15.4-4.el8.ML.2.src.rpm
    MD5: 830a78978a1b51450f1bcd0a15168a8e
    SHA-256: e947838df68aee3b317c7e403490414075409365910d2845668ee491f16fd690
    Size: 1.22 MB

Asianux Server 8 for x86_64
  1. shim-unsigned-ia32-15.4-4.el8.ML.2.x86_64.rpm
    MD5: 2de9f9996579f8bc7d1f729f444b032f
    SHA-256: ca04aa1d308e16c0bff96c8f8406eb076d116cc1607be63cea3878486131e14f
    Size: 399.34 kB
  2. shim-unsigned-x64-15.4-4.el8.ML.2.x86_64.rpm
    MD5: 968739a11f528fdf3f39d92a048c0076
    SHA-256: 2d6767f48a3be6e5e890e2d423c17270b864411975ad334b8bf4cb6914f29bca
    Size: 447.30 kB