Debian DSA-4735-1 : grub2 - security update

Medium Nessus Plugin ID 139099

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: 2020/07/30

Updated: 2020/09/24

Dependencies: 12634

Risk Information

Risk Factor: Medium

CVSS Score Source: CVE-2020-14309

CVSS v2.0

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

Temporal Vector: CVSS2#E:U/RL:OF/RC:C

CVSS v3.0

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: CVSS:3.0/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: 2020/07/29

Vulnerability Publication Date: 2020/07/29

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