cisco-sa-iosxr-pxe-unsign-code-exec-qAa78fD2: Cisco IOS XR Software Enhanced Preboot eXecution Environment Unsigned Code Execution Vulnerability

Published Nov 4, 2020
·
Updated

A vulnerability in the enhanced Preboot eXecution Environment (PXE) boot loader for Cisco IOS XR 64-bit Software could allow an unauthenticated, remote attacker to execute unsigned code during the PXE boot process on an affected device. The PXE boot loader is part of the BIOS and runs over the management interface of hardware platforms that are running Cisco IOS XR Software only. The vulnerability exists because internal commands that are issued when the PXE network boot process is loading a software image are not properly verified. An attacker could exploit this vulnerability by compromising the PXE boot server and replacing a valid software image with a malicious one. Alternatively, the attacker could impersonate the PXE boot server and send a PXE boot reply with a malicious file. A successful exploit could allow the attacker to execute unsigned code on the affected device. Note: To fix this vulnerability, both the Cisco IOS XR Software and the BIOS must be upgraded. The BIOS code is included in Cisco IOS XR Software but might require additional installation steps. For further information, see the Fixed Software section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pxe-unsign-code-exec-qAa78fD2

Credit

This vulnerability was found by Martin Ramsdale(Cisco during internal security testing)

Affected Software

6 affected components
Cisco ASR 9000 Series PIDs1
Cisco NCS 1000 Series PIDs1
Cisco NCS 540 PIDs
Cisco NCS 560 PIDs
Cisco NCS 5000 Series PIDs1
Cisco NCS 5500 Series PIDs1

Event History

Nov 4, 2020
Advisory Published
via Cisco·04:00 PM

Child vulnerabilities

Contains the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2?

The severity of Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2 is classified as critical due to its potential for remote code execution.

2

How do I fix Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2?

To fix Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2, it is recommended to update the affected devices to a patched version of the Cisco IOS XR software.

3

What products are affected by Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2?

Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2 affects various Cisco products including the ASR 9000 Series, NCS 1000 Series, and NCS 5000 and 5500 Series routers.

4

Can Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2 be exploited remotely?

Yes, Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2 can be exploited remotely by unauthenticated attackers during the PXE boot process.

5

What are the potential impacts of Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2?

The potential impacts of Cisco-SA-IOSXR-PXE-UNSIGN-CODE-EXEC-QAa78fD2 include unauthorized execution of unsigned code, leading to compromised devices.

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