Debian dla-3813 : shim-helpers-amd64-signed-template - security update

high Nessus Plugin ID 196989


The remote Debian host is missing one or more security-related updates.


The remote Debian 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-3813 advisory.

- A flaw was found in Shim when an error happened while creating a new ESL variable. If Shim fails to create the new variable, it tries to print an error message to the user; however, the number of parameters used by the logging function doesn't match the format string used by it, leading to a crash under certain circumstances. (CVE-2023-40546)

- A remote code execution vulnerability was found in Shim. The Shim boot support trusts attacker-controlled values when parsing an HTTP response. This flaw allows an attacker to craft a specific malicious HTTP request, leading to a completely controlled out-of-bounds write primitive and complete system compromise.
This flaw is only exploitable during the early boot phase, an attacker needs to perform a Man-in-the- Middle or compromise the boot server to be able to exploit this vulnerability successfully.

- A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes memory corruption and can lead to a crash or data integrity issues during the boot phase. (CVE-2023-40548)

- An out-of-bounds read flaw was found in Shim due to the lack of proper boundary verification during the load of a PE binary. This flaw allows an attacker to load a crafted PE binary, triggering the issue and crashing Shim, resulting in a denial of service. (CVE-2023-40549)

- An out-of-bounds read flaw was found in Shim when it tried to validate the SBAT information. This issue may expose sensitive data during the system's boot phase. (CVE-2023-40550)

- A flaw was found in the MZ binary format in Shim. An out-of-bounds read may occur, leading to a crash or possible exposure of sensitive data during the system's boot phase. (CVE-2023-40551)

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


Upgrade the shim-helpers-amd64-signed-template packages.

See Also

Plugin Details

Severity: High

ID: 196989

File Name: debian_DLA-3813.nasl

Version: 1.0

Type: local

Agent: unix

Published: 5/14/2024

Updated: 5/14/2024

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information


Risk Factor: Critical

Score: 9.2


Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2023-40547


Risk Factor: High

Base Score: 8.3

Temporal Score: 7.2

Vector: CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:C/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:shim-helpers-arm64-signed-template, p-cpe:/a:debian:debian_linux:shim-helpers-i386-signed-template, cpe:/o:debian:debian_linux:10.0, p-cpe:/a:debian:debian_linux:shim-helpers-amd64-signed-template, p-cpe:/a:debian:debian_linux:shim-unsigned

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/13/2024

Vulnerability Publication Date: 12/11/2023

Reference Information

CVE: CVE-2023-40546, CVE-2023-40547, CVE-2023-40548, CVE-2023-40549, CVE-2023-40550, CVE-2023-40551