Описание
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.
A flaw was found in GRUB 2, 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 kernel further loads and executes the table, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code.
Отчет
For a successful attack to occur, the attacker needs to triage the environment to determine where the lockdown variable symbol is placed in memory when the kernel is loaded. Then the SSDT table needs to be written accordingly into this memory position and the grub.cfg file needs to be changed to load the table during the boot time.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 7 | fwupd | Affected | ||
| Red Hat Enterprise Linux 7 | fwupdate | Affected | ||
| Red Hat Enterprise Linux 7 | shim | Not affected | ||
| Red Hat Enterprise Linux 8 | fwupdate | Will not fix | ||
| Red Hat Enterprise Linux 7 | grub2 | Fixed | RHSA-2021:0699 | 02.03.2021 |
| Red Hat Enterprise Linux 7.2 Advanced Update Support | grub2 | Fixed | RHSA-2021:0704 | 02.03.2021 |
| Red Hat Enterprise Linux 7.3 Advanced Update Support | grub2 | Fixed | RHSA-2021:0703 | 02.03.2021 |
| Red Hat Enterprise Linux 7.4 Advanced Update Support | grub2 | Fixed | RHSA-2021:0702 | 02.03.2021 |
| Red Hat Enterprise Linux 7.4 Telco Extended Update Support | grub2 | Fixed | RHSA-2021:0702 | 02.03.2021 |
| Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions | grub2 | Fixed | RHSA-2021:0702 | 02.03.2021 |
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Дополнительная информация
Статус:
EPSS
7.5 High
CVSS3
Связанные уязвимости
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.
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.
A flaw was found in grub2 in versions prior to 2.06, where it incorrec ...
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.
EPSS
7.5 High
CVSS3