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AUSCERT External Security Bulletin Redistribution
ESB-2023.1721
Cisco IOS XE SD-WAN Software Command Injection Vulnerability
23 March 2023
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco IOS XE SD-WAN Software
Publisher: Cisco Systems
Operating System: Cisco
Resolution: Patch/Upgrade
CVE Names: CVE-2023-20035
Original Bulletin:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-sdwan-VQAhEjYw
Comment: CVSS (Max): 7.8 CVE-2023-20035 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
CVSS Source: Cisco Systems
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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Cisco IOS XE SD-WAN Software Command Injection Vulnerability
Priority: High
Advisory ID: cisco-sa-ios-xe-sdwan-VQAhEjYw
First Published: 2023 March 22 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvx72976 CSCwc41942
CVE Names: CVE-2023-20035
Summary
o A vulnerability in the CLI of Cisco IOS XE SD-WAN Software could allow an
authenticated, local attacker to execute arbitrary commands with elevated
privileges.
This vulnerability is due to insufficient input validation by the system
CLI. An attacker with privileges to run commands could exploit this
vulnerability by first authenticating to an affected device using either
local terminal access or a management shell interface and then submitting
crafted input to the system CLI. A successful exploit could allow the
attacker to execute commands on the underlying operating system with root
-level privileges. An attacker with limited user privileges could use this
vulnerability to gain complete control over the system.
Note: For additional information about specific impacts, see the Details
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-ios-xe-sdwan-VQAhEjYw
This advisory is part of the March 2023 release of the Cisco IOS and IOS XE
Software Security Advisory Bundled Publication. For a complete list of the
advisories and links to them, see Cisco Event Response: March 2023
Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled
Publication .
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a vulnerable release of universal Cisco IOS XE Software in controller mode
or a vulnerable release of standalone Cisco IOS XE SD-WAN Software:
1000 Series Integrated Services Routers (ISRs)
4000 Series ISRs
ASR 1000 Series Aggregation Services Routers
Catalyst 8000 Edge Platforms Family
Cloud Services Router (CSR) 1000V Series
For information about which Cisco software releases are vulnerable, see the
Fixed Software section of this advisory.
Note: The standalone Cisco IOS XE SD-WAN Software release images are
separate from the universal Cisco IOS XE Software release images. The
SD-WAN feature was first integrated into universal Cisco IOS XE Software
with Release 17.2.1r. For more information, see the Cisco SD-WAN Getting
Started Guide .
Determine the Device Configuration
There are two methods for determining whether the controller mode is
enabled on a device that is running universal Cisco IOS XE Software. A
device must be in controller mode to use the Cisco SD-WAN feature.
Option 1: Use the show running-config | include sdwan Command
To determine whether the controller mode is enabled on a device, use the
show running-config | include sdwan command and check the tunnel mode in
the output. If the command returns tunnel mode sdwan , the SD-WAN feature
is enabled. Therefore, the device is in controller mode and is considered
vulnerable. If the command returns no output or the command does not exist,
the device is not affected by this vulnerability.
The following example shows the output of the show running-config | include
sdwan command on a device that is in controller mode:
Router# show running-config | include sdwan
tunnel mode sdwan
Router#
Option 2: Use the show version Command
Alternatively, use the show version command to determine whether the device
is in controller mode. The end of the output includes the router operating
mode, which indicates whether the device is in controller mode.
The following example shows part of the show version command output on a
device that is in controller mode:
Router# show version
.
.
.
Router operating mode: Controller-Managed
.
.
.
Products Confirmed Not Vulnerable
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 or platforms:
IOS Software
IOS XE Software in autonomous mode
IOS XR Software
Meraki products
NX-OS Software
SD-WAN vBond Orchestrator Software
SD-WAN vEdge Routers
SD-WAN vEdge Cloud Routers
SD-WAN vManage Software
SD-WAN vSmart Controller Software
Details
o The impact of exploitation may differ depending on the user access
privilege levels on an affected device.
The Security Impact Rating (SIR) for this vulnerability is High for
affected devices where low-privileged users are authorized to log in and
run command line operations. In this scenario, a user with limited
privileges could exploit this vulnerability to gain complete control over
the affected device.
Potential impacts are lower for affected devices where only high-privileged
administrative users are authorized to log in. An administrative user gains
fewer privileges through exploitation of this vulnerability, reducing the
impact.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o Cisco has released free software updates that address the vulnerability
described in this advisory. Customers with service contracts that entitle
them to regular software updates should obtain security fixes through their
usual update channels.
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.
The Cisco Support and Downloads page on Cisco.com provides information
about licensing and downloads. This page can also display customer device
support coverage for customers who use the My Devices tool.
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.
Cisco IOS and IOS XE Software
To help customers determine their exposure to vulnerabilities in Cisco IOS
and IOS XE Software, Cisco provides the Cisco Software Checker . This tool
identifies any Cisco security advisories that impact a specific software
release and the earliest release that fixes the vulnerabilities that are
described in each advisory ("First Fixed"). If applicable, the tool also
returns the earliest release that fixes all the vulnerabilities that are
described in all the advisories that the Software Checker identifies
("Combined First Fixed").
To use the tool, go to the Cisco Software Checker page and follow the
instructions. Alternatively, use the following form to determine whether a
release is affected by any Cisco Security Advisory. To use the form, follow
these steps:
1. Choose which advisories the tool will search-only this advisory, only
advisories with a Critical or High Security Impact Rating (SIR) , or
all advisories.
2. Enter a release number-for example, 15.9(3)M2 or 17.3.3.
3. Click Check .
Exploitation and Public Announcements
o 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.
Source
o This vulnerability was found during internal security testing.
Cisco Security Vulnerability Policy
o 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.
Subscribe to Cisco Security Notifications
o Subscribe
Related to This Advisory
o Cisco Event Response: March 2023 Semiannual Cisco IOS and IOS XE Software
Security Advisory Bundled Publication
URL
o https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-xe-sdwan-VQAhEjYw
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2023-MAR-22 |
+----------+---------------------------+----------+--------+--------------+
Legal Disclaimer
o THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND
OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT
OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES
THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A standalone copy or paraphrase of the text of this document that omits the
distribution URL is an uncontrolled copy and may lack important information
or contain factual errors. The information in this document is intended for
end users of Cisco products.
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