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AUSCERT External Security Bulletin Redistribution
ESB-2021.3176
Cisco Access Points SSH Management Privilege Escalation Vulnerability
23 September 2021
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AusCERT Security Bulletin Summary
---------------------------------
Product: Access Points
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Root Compromise -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2021-1419
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cisco-ap-LLjsGxv
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco Access Points SSH Management Privilege Escalation Vulnerability
Priority: High
Advisory ID: cisco-sa-cisco-ap-LLjsGxv
First Published: 2021 September 22 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvw71885
CVE Names: CVE-2021-1419
CWEs: CWE-284
Summary
o A vulnerability in the SSH management feature of multiple Cisco Access
Points (APs) platforms could allow a local, authenticated user to modify
files on the affected device and possibly gain escalated privileges.
The vulnerability is due to improper checking on file operations within the
SSH management interface. A network administrator user could exploit this
vulnerability by accessing an affected device through SSH management to
make a configuration change. A successful exploit could allow the attacker
to gain privileges equivalent to the root user.
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-cisco-ap-LLjsGxv
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a vulnerable software release with the access point SSH management feature
enabled:
Aironet 1540 Series APs
Aironet 1560 Series APs
Aironet 1800 Series APs
Aironet 2800 Series APs
Aironet 3800 Series APs
Aironet 4800 APs
Catalyst 9100 APs
Catalyst IW 6300 APs
ESW6300 Series APs
Integrated Access Point on 1100 Integrated Services Routers
Determine Whether SSH Management is Enabled
Note : The SSH management feature is not enabled by default.
Customers using Cisco IOS XE Software can verify whether SSH management is
enabled on the access point by checking the following settings in the Cisco
Wireless LAN Controller web-based management interface:
Configuration > Tags & Profiles > AP Join > Click on profile name > Verify
SSH Configuration
If the SSH box is checked, the SSH management feature is enabled.
Customers using Cisco AireOS Software can verify whether SSH management has
been enabled globally on managed access points by checking Wireless >
Global Configuration and verifying the Global Telnet SSH setting.
Customers can also verify whether SSH management is enabled on the access
point by running the show running-config command and examining the SSH
State value.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
Cisco Wireless LAN Controller devices that run either Cisco AireOS Software
or Cisco IOS XE Software are not affected by this vulnerability.
Cisco has confirmed that this vulnerability does not affect any Cisco
Access Point series that is not listed in the Vulnerable Products section
of this advisory. Access points that run Cisco IOS Software are not
affected by this vulnerability.
Details
o Exploitation of this vulnerability requires the SSH feature to be enabled.
Devices without SSH management enabled are not vulnerable to exploitation.
The SSH management feature is not required to remotely administer an access
point from a Cisco Wireless LAN Controller device.
An attacker must know the SSH management credentials locally defined on the
access point in order to log in to an affected access point to exploit this
vulnerability.
Workarounds
o There are no workarounds that address this vulnerability.
However, customers who do not use the SSH management feature can disable it
to close the attack vector on affected devices.
While this mitigation has been deployed and was proven successful in a test
environment, customers should determine the applicability and effectiveness
in their own environment and under their own use conditions. Customers
should be aware that any workaround or mitigation that is implemented may
negatively impact the functionality or performance of their network based
on intrinsic customer deployment scenarios and limitations. Customers
should not deploy any workarounds or mitigations before first evaluating
the applicability to their own environment and any impact to such
environment.
Fixed Software
o 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 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
The process to upgrade the APs requires administrators to upgrade the
wireless controller to which the APs are registered.
Customers are advised to upgrade to an appropriate fixed software release
as indicated in the following table(s):
Access Points Managed by Wireless LAN Controller
Cisco Wireless LAN Controller Software First Fixed Release for This
Release Vulnerability
8.5 and earlier Not affected.
8.10 8.10.151.0
Access Points Managed by Catalyst 9800 Wireless Controller
Cisco Catalyst 9800 Wireless Controller First Fixed Release for This
Software Release Vulnerability
16.12 16.12.6
17.2 and earlier Migrate to a fixed release.
17.3 17.3.3
17.4 Migrate to a fixed release.
17.5 Not affected.
17.6 Not affected.
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 Cisco would like to thank Richard Atkin of ITGL for reporting this
vulnerability.
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.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cisco-ap-LLjsGxv
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2021-SEP-22 |
+----------+---------------------------+----------+--------+--------------+
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