A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device. This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to. 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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2 This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication.
A vulnerability in the SSH Server process of Cisco IOS XR Software could allow an authenticated, remote attacker to overwrite and read arbitrary files on the local device.
This vulnerability is due to insufficient input validation of arguments that are supplied by the user for a specific file transfer method. An attacker with lower-level privileges could exploit this vulnerability by specifying Secure Copy Protocol (SCP) parameters when authenticating to a device. A successful exploit could allow the attacker to elevate their privileges and retrieve and upload files on a device that they should not have access to.
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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-scp-inject-QwZOCv2
This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: September 2021 Cisco IOS XR Software Security Advisory Bundled Publication.
This vulnerability affects Cisco IOS XR Software releases earlier than Release 7.3.2 and Release 7.4.1.
Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect the following Cisco products:
There are no workarounds that address this vulnerability.
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.html
Additionally, 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 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.
Cisco fixed this vulnerability in Cisco IOS XR Software releases 7.3.2 and 7.4.1.
Cisco has released the following SMUs to address this vulnerability. Customers who require SMUs for platforms or releases that are not listed are advised to contact their support organization.
| Cisco IOS XR Software Release | Platform | SMU Name |
|---|---|---|
| 6.2.3 | ASR9K-PX | asr9k-px-6.2.3.CSCvx48017 |
| 6.3.3 | ASR9K-PX | asr9k-px-6.3.3.CSCvx48017 |
| 6.3.15 | NCS5500 | ncs5500-6.3.15.CSCvx48017 |
| 6.4.2 | ASR9K-PX | asr9k-px-6.4.2.CSCvx48017 |
| 6.5.2 | NCS5500 | ncs5500-6.5.2.CSCvx48017 |
| 6.5.3 | ASR9K-PX | asr9k-px-6.5.3.CSCvx48017 |
| 6.5.3 | XRV9K | xrv9k-6.5.3.CSCvx48017 |
| 6.6.12 | IOSXRWBD | iosxrwbd-6.6.12.CSCvx48017 |
| 6.6.25 | NCS5500 | ncs5500-6.6.25.CSCvx48017 |
| 6.6.3 | IOSXRWBD | iosxrwbd-6.6.3.CSCvx48017 |
| 6.6.3 | NCS5500 | ncs5500-6.6.3.CSCvx48017 |
| 6.7.3 | ASR9K-PX | asr9k-px-6.7.3.CSCvx48017 |
| 6.7.4 | CRS-PX | hfr-px-6.7.4.CSCvx48017 |
| 7.0.1 | NCS5500 | ncs5500-7.0.1.CSCvx48017 |
| 7.2.1 | IOSXRWBD | iosxrwbd-7.2.1.CSCvx48017 |
| 7.2.1 | NCS1001 | ncs1001-7.2.1.CSCvx48017 |
| 7.2.2 | IOSXRWBD | iosxrwbd-7.2.2.CSCvx48017 |
| 7.2.2 | NCS5500 | ncs5500-7.2.2.CSCvx48017 |
| 7.2.2 | XRV9K | xrv9k-7.2.2.CSCvx48017 |
| 7.1.2 | XRV9K | xrv9k-7.1.2.CSCvx48017 |
| 7.1.2 | NCS5500 | ncs5500-7.1.2.CSCvx48017 |
| 7.1.2 | NCS560 | ncs560-7.1.2.CSCvx48017 |
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.
This vulnerability was found during internal security testing.
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.
| Version | Description | Section | Status | Date |
|---|---|---|---|---|
| 1.1 | Added additional SMUs. | Fixed Software | Final | 2021-SEP-16 |
| 1.0 | Initial public release. | - | Final | 2021-SEP-08 |
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