The remote CentOS Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2020:3217 advisory.

  - A flaw was found in grub2, prior to version 2.06. An attacker may use the GRUB 2 flaw to hijack and tamper     the GRUB verification process. This flaw also allows the bypass of Secure Boot protections. In order to     load an untrusted or modified kernel, an attacker would first need to establish access to the system such     as gaining physical access, obtain the ability to alter a pxe-boot network, or have remote access to a     networked system with root access. With this access, an attacker could then craft a string to cause a     buffer overflow by injecting a malicious payload that leads to arbitrary code execution within GRUB. The     highest threat from this vulnerability is to data confidentiality and integrity as well as system     availability. (CVE-2020-10713)

  - In grub2 versions before 2.06 the grub memory allocator doesn't check for possible arithmetic overflows on     the requested allocation size. This leads the function to return invalid memory allocations which can be     further used to cause possible integrity, confidentiality and availability impacts during the boot     process. (CVE-2020-14308)

  - There's an issue with grub2 in all versions before 2.06 when handling squashfs filesystems containing a     symbolic link with name length of UINT32 bytes in size. The name size leads to an arithmetic overflow     leading to a zero-size allocation further causing a heap-based buffer overflow with attacker controlled     data. (CVE-2020-14309)

  - There is an issue on grub2 before version 2.06 at function read_section_as_string(). It expects a font     name to be at max UINT32_MAX - 1 length in bytes but it doesn't verify it before proceed with buffer     allocation to read the value from the font value. An attacker may leverage that by crafting a malicious     font file which has a name with UINT32_MAX, leading to read_section_as_string() to an arithmetic overflow,     zero-sized allocation and further heap-based buffer overflow. (CVE-2020-14310)

  - There is an issue with grub2 before version 2.06 while handling symlink on ext filesystems. A filesystem     containing a symbolic link with an inode size of UINT32_MAX causes an arithmetic overflow leading to a     zero-sized memory allocation with subsequent heap-based buffer overflow. (CVE-2020-14311)

  - GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be     bypassed. This only affects systems where the kernel signing certificate has been imported directly into     the secure boot database and the GRUB image is booted directly without the use of shim. This issue affects     GRUB2 version 2.04 and prior versions. (CVE-2020-15705)

  - GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability     which can be triggered by redefining a function whilst the same function is already executing, leading to     arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and     prior versions. (CVE-2020-15706)

  - Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux     component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2     upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number     of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files     on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot     restrictions. This issue affects GRUB2 version 2.04 and prior versions. (CVE-2020-15707)

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

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CentOS 7 : grub2 (RHSA-2020:3217)

high Nessus Plugin ID 139236

Version 1.9

Version 1.8

Version 1.7

Version 1.7

Version 1.9 Oct 9, 2024, 10:24 PM CVSS metrics ("Cvssv4 score" set to 0.0) CVSSv2 severity (based on None, severity decreased from "High" to "Low") Detection (updated detection logic) Plugin metadata Reference Plugin Feed: 202410092224
Version 1.8 Feb 27, 2024, 4:10 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: 202402271610
Version 1.7 Feb 27, 2024, 1:50 PM CVSS temporal metrics ("CVSSv2 temporal vector" set to "CVSS2#E:POC/RL:OF/RC:C") CVSS temporal metrics ("CVSSv3 temporal vector" set to "CVSS:3.0/E:P/RL:O/RC:C") Exploit attributes ("Exploit available" set to "True") Exploit attributes ("Exploitability ease" changed from "No known exploits are available" to "Exploits are available") Plugin Feed: 202402271350
Version 1.7 Dec 6, 2022, 6:53 AM Reference Plugin Feed: 202212060653