Cisco FXOS Software for Firepower 4100/9300 Series Appliances Secure Boot Bypass (cisco-sa-fxos-sbbp-XTuPkYTn)

high Nessus Plugin ID 141832
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VPR Score: 5.9


The remote device is missing a vendor-supplied security patch.


According to its self-reported version, Cisco Firepower Extensible Operating System (FXOS) is affected by a secure boot bypass vulnerability. The vulnerability is due to insufficient protections of the secure boot process. A local attacker can exploit this vulnerability by injecting code into a specific file that is then referenced during the device boot process. A successful exploit can allow the attacker to break the chain of trust and inject code into the boot process of the device which would be executed at each boot and maintain persistence across reboots.

Please see the included Cisco BIDs and Cisco Security Advisory for more information.


Upgrade to the relevant fixed version referenced in Cisco bug ID CSCvt31171.

See Also

Plugin Details

Severity: High

ID: 141832

File Name: cisco-sa-fxos-sbbp-XTuPkYTn.nasl

Version: 1.9

Type: local

Family: CISCO

Published: 10/23/2020

Updated: 3/29/2021

Dependencies: cisco_enumerate_firepower.nbin

Risk Information

Risk Factor: High

VPR Score: 5.9

CVSS Score Source: CVE-2020-3455

CVSS v2.0

Base Score: 7.2

Temporal Score: 5.3

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

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

CVSS v3.0

Base Score: 7.8

Temporal Score: 6.8

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

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

Vulnerability Information

CPE: cpe:/o:cisco:fxos

Required KB Items: installed_sw/FXOS

Exploit Ease: No known exploits are available

Patch Publication Date: 10/21/2020

Vulnerability Publication Date: 10/21/2020

Reference Information

CVE: CVE-2020-3455


CISCO-SA: cisco-sa-fxos-sbbp-XTuPkYTn

IAVA: 2020-A-0487

CWE: 693