The version of grub2 installed on the remote host is prior to 2.06-2. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2021-1684 advisory.

  - A flaw was found in the grub2-set-bootflag utility of grub2. A local attacker could run this utility under     resource pressure (for example by setting RLIMIT), causing grub2 configuration files to be truncated and     leaving the system unbootable on subsequent reboots. (CVE-2019-14865)

  - 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-2020-14372)

  - 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-2020-25632)

  - 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-2020-25647)

  - 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-2020-27749)

  - 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-2020-27779)

  - 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-2021-20225)

  - 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. (CVE-2021-20233)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

Amazon Linux 2 : grub2 (ALAS-2021-1684)

high Nessus Plugin ID 151799

Version 1.5

Version 1.4

Version 1.4

Version 1.3

Version 1.5 Mar 5, 2024, 5:50 PM Exploit attributes ("Exploitability ease" changed from "No known exploits are available" to "Exploits are available") Plugin Feed: 202403051750
Version 1.4 Mar 5, 2024, 7:01 AM CVE (set "CVE" coverage to "CVE-2019-14865,CVE-2020-14372,CVE-2020-25632,CVE-2020-25647,CVE-2020-27749,CVE-2020-27779,CVE-2021-20225,CVE-2021-20233") Detection (updated detection logic) Exploit attributes ("Exploitability ease" changed from "Exploits are available" to "No known exploits are available") Plugin metadata Plugin Feed: 202403050701
Version 1.4 Mar 5, 2024, 2:40 PM Exploit attributes ("Exploitability ease" changed from "No known exploits are available" to "Exploits are available") Plugin Feed: 202403051440
Version 1.3 Dec 7, 2023, 3:25 PM CVSS temporal metrics ("CVSSv2 temporal vector" set to "CVSS2#E:POC/RL:OF/RC:C". "CVSSv3 temporal vector" set to "CVSS:3.0/E:P/RL:O/RC:C") Exploit attributes ("Exploit available" set to "True". "Exploitability ease" changed from "No known exploits are available" to "Exploits are available") Plugin Feed: 202312071525