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AUSCERT External Security Bulletin Redistribution
ESB-2021.1020
Cisco Aironet Access Points multiple vulnerabilities
25 March 2021
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Aironet Access Points software
Cisco Aironet Access Points FlexConnect software
Publisher: Cisco Systems
Operating System: Cisco
Impact/Access: Overwrite Arbitrary Files -- Existing Account
Denial of Service -- Remote/Unauthenticated
Access Confidential Data -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2021-1439 CVE-2021-1437 CVE-2021-1423
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ap-foverwrt-HyVXvrtb
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aironet-mdns-dos-E6KwYuMx
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-aironet-info-disc-BfWqghj
Comment: This bulletin contains three (3) Cisco Systems security advisories.
- --------------------------BEGIN INCLUDED TEXT--------------------
Cisco Aironet Access Points Arbitrary File Overwrite Vulnerability
Priority: Medium
Advisory ID: cisco-sa-ap-foverwrt-HyVXvrtb
First Published: 2021 March 24 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvu98274
CVE Names: CVE-2021-1423
CWEs: CWE-668
Summary
o A vulnerability in the implementation of a CLI command in Cisco Aironet
Access Points (AP) could allow an authenticated, local attacker to
overwrite files in the flash memory of the device.
This vulnerability is due to insufficient input validation for a specific
command. An attacker could exploit this vulnerability by issuing a command
with crafted arguments. A successful exploit could allow the attacker to
overwrite or create files with data that is already present in other files
that are hosted on the affected device.
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-ap-foverwrt-HyVXvrtb
Affected Products
o Vulnerable Products
At the time of publication, this vulnerability affected the following Cisco
products if they were running a vulnerable release of Cisco Aironet Series
Access Points Software:
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
Integrated AP on 1100 Integrated Services Routers
6300 Series Embedded Services APs (ESW6300)
For information about which Cisco software releases were vulnerable at the
time of publication, see the Fixed Software section of this advisory. See
the Details section in the bug ID(s) at the top of this advisory for the
most complete and current information.
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 any Cisco
Access Point series that is not listed in the Vulnerable Products section
of this advisory.
Workarounds
o There are no workarounds that address this vulnerability.
Fixed Software
o 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.
Fixed Releases
At the time of publication, the release information in the following table
(s) was accurate. See the Details section in the bug ID(s) at the top of
this advisory for the most complete and current information.
The left column lists Cisco software releases, and the right column
indicates whether a release was affected by the vulnerability described in
this advisory and which release included the fix for this vulnerability.
Cisco Access Points Managed by Wireless LAN Controller or Mobility Express
Cisco Wireless LAN Controller Software First Fixed Release for This
Release Vulnerability
8.4 and earlier Migrate to a fixed release.
8.5 8.5.171.0
8.6 - 8.9 Migrate to a fixed release.
8.10 8.10.130.0
Cisco Access Points Managed by Catalyst 9800 Wireless Controller or
Embedded Wireless Controller on Catalyst Access Points
Cisco Catalyst 9800 Controller Software First Fixed Release for This
Release Vulnerability
16.11 and earlier Migrate to a fixed release.
16.12 16.12.5
17.1 - 17-2 Migrate to a fixed release.
17.3 and later Not vulnerable.
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 Chris Bellows of Atredis Partners and HD Moore of
Rumble 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-ap-foverwrt-HyVXvrtb
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2021-MAR-24 |
+----------+---------------------------+----------+--------+--------------+
- --------------------------------------------------------------------------------
Cisco Aironet Access Points FlexConnect Multicast DNS Denial of Service
Vulnerability
Priority: High
Advisory ID: cisco-sa-aironet-mdns-dos-E6KwYuMx
First Published: 2021 March 24 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvw63560
CVE Names: CVE-2021-1439
CWEs: CWE-120
Summary
o A vulnerability in the multicast DNS (mDNS) gateway feature of Cisco
Aironet Series Access Points Software could allow an unauthenticated,
adjacent attacker to cause a denial of service (DoS) condition on an
affected device.
This vulnerability is due to insufficient input validation of incoming mDNS
traffic. An attacker could exploit this vulnerability by sending a crafted
mDNS packet to an affected device through a wireless network that is
configured in FlexConnect local switching mode or through a wired network
on a configured mDNS VLAN. A successful exploit could allow the attacker to
cause the access point (AP) to reboot, resulting in a DoS condition.
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-aironet-mdns-dos-E6KwYuMx
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a vulnerable release of Cisco Aironet Series Access Points Software, they
have at least one wireless network configured in FlexConnect local
switching mode, and the mDNS gateway feature is enabled on the wireless
controller for that wireless network or one of the wired VLANs associated
to it:
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
Integrated AP on 1100 Integrated Services Routers
6300 Series Embedded Services APs (ESW6300)
Determine the Status of FlexConnect Local Switching Mode
To determine whether a wireless network is running in FlexConnect local
switching mode, complete the following steps:
1. Access the wireless controller management web interface.
2. Choose Configuration > Tags & Profiles > Policy and open the profile
that is associated to the wireless network.
3. In the General tab, check the status of the Central Switching
parameter.
If Central Switching is disabled, the network is running in FlexConnect
local switching mode
Determine the Status of the mDNS Gateway feature
To determine whether the mDNS Gateway is enabled on a wireless network,
complete the following steps:
1. Access the wireless controller management web interface.
2. Choose Configuration > Tags & Profiles > WLANs and select the wireless
network.
3. On the Advanced tab, check the value selected in the mDNS Mode
drop-down list.
To determine whether the mDNS Gateway is enabled on a wired VLAN, complete
the following steps:
1. Access the wireless controller management web interface.
2. Choose Configuration > Services > mDNS .
3. In the mDNS Flex Profile section, click the profile name.
4. Check the VLANs field to see which VLANs it is enabled for.
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 any Cisco
Access Point series that is not listed in the Vulnerable Products section
of this advisory.
Cisco has also confirmed that this vulnerability does not affect Cisco
Wireless Controller and Cisco Mobility Express because they do not support
enabling the mDNS Gateway feature on a FlexConnect wireless network.
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 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 that the APs are registered to.
Customers are advised to upgrade to an appropriate fixed software release
as indicated in the following table(s). To ensure a complete upgrade
solution, consider that this advisory is part of a collection that includes
the following advisories:
cisco-sa-aironet-info-disc-BfWqghj : Cisco Aironet Access Points
FlexConnect Upgrade Information Disclosure Vulnerability
cisco-sa-aironet-mdns-dos-E6KwYuMx : Cisco Aironet Access Points
FlexConnect Multicast DNS Denial of Service Vulnerability
cisco-sa-ap-privesc-wEVfp8Ud : Cisco Access Point Software Arbitrary
Code Execution Vulnerability
Cisco Access Points Managed by Catalyst 9800 Wireless Controller or
Embedded Wireless Controller on Catalyst Access Points
Cisco Catalyst 9800 First Fixed First Fixed Release for All
Wireless Controller Release for This Vulnerabilities Described in This
Software Release Vulnerability Collection of Advisories
17.2 and earlier Not vulnerable. Migrate to a fixed release.
17.3 17.3.3 17.3.3
17.4 Migrate to a 17.5.1 (Mar 2021)
fixed release.
17.5 and later Not vulnerable. Not vulnerable.
Cisco Access Points Managed by Wireless LAN Controller or Mobility Express
Cisco Wireless Controller and Cisco Mobility Express do not support
enabling the mDNS Gateway feature on a FlexConnect wireless network, so
these access points are not affected by this vulnerability.
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.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-aironet-mdns-dos-E6KwYuMx
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2021-MAR-24 |
+----------+---------------------------+----------+--------+--------------+
- --------------------------------------------------------------------------------
Cisco Aironet Access Points FlexConnect Upgrade Information Disclosure
Vulnerability
Priority: High
Advisory ID: cisco-sa-aironet-info-disc-BfWqghj
First Published: 2021 March 24 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds available
Cisco Bug IDs: CSCvv91666
CVE Names: CVE-2021-1437
CWEs: CWE-275
Summary
o A vulnerability in the FlexConnect Upgrade feature of Cisco Aironet Series
Access Points Software could allow an unauthenticated, remote attacker to
obtain confidential information from an affected device.
This vulnerability is due to an unrestricted Trivial File Transfer Protocol
(TFTP) configuration. An attacker could exploit this vulnerability by
sending a specific TFTP request to an affected device. A successful exploit
could allow the attacker to download any file from the filesystem of the
affected access point (AP).
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-aironet-info-disc-BfWqghj
Affected Products
o Vulnerable Products
This vulnerability affects the following Cisco products if they are running
a vulnerable release of Cisco Aironet Series Access Points Software and are
acting as the FlexConnect AP Upgrade Master:
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
Integrated AP on 1100 Integrated Services Routers
6300 Series Embedded Services APs (ESW6300)
For information about which Cisco software releases are vulnerable, see the
Fixed Software section of this advisory.
Determine the Device Configuration
To determine whether a device is acting as the FlexConnect AP Upgrade
Master, complete the following steps:
1. Log in to the Wireless LAN Controller management web interface.
2. Choose Wireless > FlexConnect Groups.
3. Click a Group Name to access the group configuration.
4. Click Image Upgrade .
5. Verify the status of the FlexConnect AP Upgrade check box:
If checked: Check which AP is configured as master from the AP Name
list.
If not checked: The FlexConnect AP Upgrade is not being used and
the devices are not affected by this vulnerability.
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 any Cisco
Access Point series that is not listed in the Vulnerable Products section
of this advisory.
Workarounds
o There are no workarounds that address this vulnerability.
However, customers can disable the FlexConnect AP Upgrade feature as a
mitigation. While this will make the image transfer less efficient, it will
prevent exploitation of this vulnerability.
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 that the APs are registered to.
Customers are advised to upgrade to an appropriate fixed software release
as indicated in the following table(s). To ensure a complete upgrade
solution, consider that this advisory is part of a collection that includes
the following advisories:
cisco-sa-aironet-info-disc-BfWqghj : Cisco Aironet Access Points
FlexConnect Upgrade Information Disclosure Vulnerability
cisco-sa-aironet-mdns-dos-E6KwYuMx : Cisco Aironet Access Points
FlexConnect Multicast DNS Denial of Service Vulnerability
cisco-sa-ap-privesc-wEVfp8Ud : Cisco Access Point Software Arbitrary
Code Execution Vulnerability
Cisco Access Points Managed by Wireless LAN Controller or Mobility Express
Cisco Wireless LAN First Fixed First Fixed Release for All
Controller Software Release for This Vulnerabilities Described in This
Release Vulnerability Collection of Advisories
Earlier than Not vulnerable. 8.10.151.0
8.10.112.0
8.10.112.0 and 8.10.142.0 8.10.151.0
later
Cisco Access Points Managed by Catalyst 9800 Wireless Controller or
Embedded Wireless Controller on Catalyst Access Points (EWC)
Cisco Catalyst 9800 First Fixed First Fixed Release for All
Wireless Controller Release for This Vulnerabilities Described in This
Software Release Vulnerability Collection of Advisories
Earlier than 17.1 Not vulnerable. 17.3.3
17.1 Migrate to a 17.3.3
fixed release.
17.2 Migrate to a 17.3.3
fixed release.
17.3 Migrate to a 17.3.3
fixed release.
17.4 and later Not vulnerable. 17.5.1 (Mar 2021)
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.
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-aironet-info-disc-BfWqghj
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2021-MAR-24 |
+----------+---------------------------+----------+--------+--------------+
- --------------------------END INCLUDED TEXT--------------------
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