Debian DSA-4735-1 : grub2 - security update

medium Nessus Plugin ID 139099
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Synopsis

The remote Debian host is missing a security-related update.

Description

Several vulnerabilities have been discovered in the GRUB2 bootloader.

- CVE-2020-10713 A flaw in the grub.cfg parsing code was found allowing to break UEFI Secure Boot and load arbitrary code.
Details can be found at https://www.eclypsium.com/2020/07/29/theres-a-hole-in-th e-boot/

- CVE-2020-14308 It was discovered that grub_malloc does not validate the allocation size allowing for arithmetic overflow and subsequently a heap-based buffer overflow.

- CVE-2020-14309 An integer overflow in grub_squash_read_symlink may lead to a heap based buffer overflow.

- CVE-2020-14310 An integer overflow in read_section_from_string may lead to a heap based buffer overflow.

- CVE-2020-14311 An integer overflow in grub_ext2_read_link may lead to a heap-based buffer overflow.

- CVE-2020-15706 script: Avoid a use-after-free when redefining a function during execution.

- CVE-2020-15707 An integer overflow flaw was found in the initrd size handling.

Further detailed information can be found at https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot

Solution

Upgrade the grub2 packages.

For the stable distribution (buster), these problems have been fixed in version 2.02+dfsg1-20+deb10u1.

See Also

https://security-tracker.debian.org/tracker/CVE-2020-10713

https://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/

https://security-tracker.debian.org/tracker/CVE-2020-14308

https://security-tracker.debian.org/tracker/CVE-2020-14309

https://security-tracker.debian.org/tracker/CVE-2020-14310

https://security-tracker.debian.org/tracker/CVE-2020-14311

https://security-tracker.debian.org/tracker/CVE-2020-15706

https://security-tracker.debian.org/tracker/CVE-2020-15707

https://www.debian.org/security/2020-GRUB-UEFI-SecureBoot

https://security-tracker.debian.org/tracker/source-package/grub2

https://packages.debian.org/source/buster/grub2

https://www.debian.org/security/2020/dsa-4735

Plugin Details

Severity: Medium

ID: 139099

File Name: debian_DSA-4735.nasl

Version: 1.6

Type: local

Agent: unix

Published: 7/30/2020

Updated: 9/24/2020

Dependencies: ssh_get_info.nasl

Risk Information

CVSS Score Source: CVE-2020-14309

VPR

Risk Factor: High

Score: 8.9

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: AV:L/AC:L/Au:N/C:P/I:P/A:P

Temporal Vector: E:U/RL:OF/RC:C

CVSS v3

Risk Factor: Medium

Base Score: 6.7

Temporal Score: 5.8

Vector: CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:grub2, cpe:/o:debian:debian_linux:10.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 7/29/2020

Vulnerability Publication Date: 7/29/2020

Reference Information

CVE: CVE-2020-10713, CVE-2020-14308, CVE-2020-14309, CVE-2020-14310, CVE-2020-14311, CVE-2020-15706, CVE-2020-15707

DSA: 4735

IAVA: 2020-A-0349