CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X
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A vulnerability in a CLI command of Cisco IOS XR Software for the Cisco 8000 Series Routers and Network Convergence System 540 Series Routers running NCS540L software images could allow an authenticated, local attacker to elevate their privilege to root. To exploit this vulnerability, an attacker would need to have a valid account on an affected device.
The vulnerability is due to insufficient validation of command line arguments. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the prompt. A successful exploit could allow an attacker with low-level privileges to escalate their privilege level to root.
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-pe-QpzCAePe
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Vulnerable Products
This vulnerability affects Cisco IOS XR Software on the following platforms:
- Cisco 8000 Series Routers if running releases earlier than the first fixed release.
- Network Convergence System 540 Series Routers 7.x releases if running releases earlier than the first fixed software release and running the NCS540L images.
Determine the Software Version
To determine if the device is running an NCS540L image, administrators can log into the device and issue the show version command. If the output indicates LNT then it is running on an affected device.
Router#show version
Cisco IOS XR Software, Version 7.0.1 LNT
Copyright (c) 2013-2019 by Cisco Systems, Inc. Build Information:
Built By : xyz
Built On : Sat Jun 29 22:45:27 2019
Build Host : iox-lnx-064
Workspace : ../7.0.1/NCS540L/ws/
Version : 7.0.1
Label : 7.0.1 cisco NCS540L
System uptime is 41 minutesProducts Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
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There are no workarounds that address this vulnerability.
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Cisco has released free software updates that address the vulnerability described in this advisory. Customers may only install and expect support for software versions and feature sets for which they have purchased a license. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license:
https://www.cisco.com/c/en/us/products/end-user-license-agreement.htmlAdditionally, customers may only download software for which they have a valid license, procured from Cisco directly, or through a Cisco authorized reseller or partner. In most cases this will be a maintenance upgrade to software that was previously purchased. Free security software updates do not entitle customers to a new software license, additional software feature sets, or major revision upgrades.
When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories page, to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Customers Without Service Contracts
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.html
Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
Fixed Releases
Customers are advised to upgrade to an appropriate fixed software release as indicated in the following table(s):
Platform Cisco IOS XR Software Release Cisco 8000 Series Routers 7.0.12
7.2.1Network Convergence System 540 Series Routers 7.2.1 Cisco has released software maintenance upgrades (SMUs) to address this vulnerability. Customers who require SMUs for other platforms and releases are advised to contact their support organization.
Cisco IOS XR Software Release Platform SMU Name 7.1.2 NCS540L ncs540l-7.1.2.CSCvs35027
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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This vulnerability was found during internal security testing.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Version Description Section Status Date 1.0 Initial public release. — Final 2021-FEB-03
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