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AUSCERT External Security Bulletin Redistribution
ESB-2022.1910
Cisco Adaptive Security Appliance Software and Firepower Threat Defense
Software IPsec IKEv2 VPN Information Disclosure Vulnerability
29 April 2022
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AusCERT Security Bulletin Summary
---------------------------------
Product: Cisco Adaptive Security Appliance Software
Firepower Threat Defense Software
Publisher: Cisco Systems
Operating System: Cisco
Resolution: Patch/Upgrade
CVE Names: CVE-2022-20742
Original Bulletin:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipsec-mitm-CKnLr4
Comment: CVSS (Max): 7.4 CVE-2022-20742 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N)
CVSS Source: Cisco Systems
Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
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Cisco Adaptive Security Appliance Software and Firepower Threat Defense
Software IPsec IKEv2 VPN Information Disclosure Vulnerability
Priority: High
Advisory ID: cisco-sa-asaftd-ipsec-mitm-CKnLr4
First Published: 2022 April 27 16:00 GMT
Version 1.0: Final
Workarounds: Yes
Cisco Bug IDs: CSCvz81480
CVE Names: CVE-2022-20742
CWEs: CWE-325
Summary
o A vulnerability in an IPsec VPN library of Cisco Adaptive Security
Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software
could allow an unauthenticated, remote attacker to read or modify data
within an IPsec IKEv2 VPN tunnel.
This vulnerability is due to an improper implementation of Galois/Counter
Mode (GCM) ciphers. An attacker in a man-in-the-middle position could
exploit this vulnerability by intercepting a sufficient number of encrypted
messages across an affected IPsec IKEv2 VPN tunnel and then using
cryptanalytic techniques to break the encryption. A successful exploit
could allow the attacker to decrypt, read, modify, and re-encrypt data that
is transmitted across an affected IPsec IKEv2 VPN tunnel.
Cisco has released software updates that address this vulnerability. There
are workarounds that address this vulnerability.
This advisory is available at the following link:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipsec-mitm-CKnLr4
This advisory is part of the April 2022 release of the Cisco ASA, FTD, and
FMC Security Advisory Bundled publication. For a complete list of the
advisories and links to them, see Cisco Event Response: April 2022 Cisco
ASA, FMC, and FTD 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 Cisco ASA Software or Cisco FTD Software and have
an IPsec IKEv2 VPN (either Remote Access or LAN-to-LAN) using a GCM cipher
configured:
Firepower 4112, 4115, 4125, and 4145 Appliances
Firepower 9300 Security Appliances with SM-40, SM-48, or SM-56
For information about which Cisco software releases are vulnerable, see the
Fixed Software section of this advisory.
Determine the IPsec IKEv2 VPN Configuration
To assess the IPsec IKEv2 VPN configuration, confirm that both of the
following are true:
IKEv2 is enabled on at least one interface
At least one configured IPsec IKEv2 proposal uses a GCM cipher
To determine whether IKEv2 is enabled on an interface, use the show
running-config crypto ikev2 | include enable CLI command. If that command
returns output, IKEv2 is enabled on at least one interface. The following
example shows the output of the show running-config crypto ikev2 | include
enable command on a device that has IKEv2 enabled on the outside interface:
firewall# show running-config crypto ikev2 | include enable
crypto ikev2 enable outside client-services port 443
To determine whether at least one IPsec IKEv2 proposal is configured to use
a GCM cipher, use the show running-config crypto ipsec | include gcm CLI
command. If that command returns output, at least one configured IPsec
IKEv2 proposal uses a GCM cipher. The following example shows the output of
the show running-config crypto ipsec | include gcm command on a device that
uses the AES-GCM cipher in an IPsec IKEv2 proposal:
firewall# show running-config crypto ipsec | include gcm
protocol esp encryption aes-gcm
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:
3000 Series Industrial Security Appliances (ISAs)
Adaptive Security Virtual Appliances (ASAv)
ASA 5505 Series Adaptive Security Appliances
ASA 5500-X Series Firewalls
ASA Services Modules for Cisco Catalyst 6500 Series Switches and Cisco
7600 Series Routers
Firepower 1000 Series
Firepower 2100 Series
Firepower 4110, 4120, 4140, and 4150 Appliances
Firepower 9300 Series Security Appliance with SM-24, SM-36, or SM-44
Firepower Management Center (FMC) Software
Firepower Threat Defense Virtual (FTDv)
Next-Generation Intrusion Prevention System (NGIPS) Software
Workarounds
o There is a workaround that addresses this vulnerability. To remove the
attack vector for this vulnerability, reconfigure all existing IPsec IKEv2
proposals to use a non-GCM cipher.
For example, if you have the following IPsec IKEv2 proposal configured:
firewall# show running-config crypto ipsec
crypto ipsec ikev2 ipsec-proposal AES-GCM
protocol esp encryption aes-gcm
protocol esp integrity null
Reconfigure that as follows:
firewall# configure terminal
firewall(config)# crypto ipsec ikev2 ipsec-proposal AES-GCM
firewall(config-ipsec-proposal)# protocol esp integrity sha-256
WARNING: GCM\GMAC are authenticated encryption algorithms.esp integrity config is ignored
firewall(config-ipsec-proposal)# protocol esp encryption aes-256
firewall# show running-config crypto ipsec
crypto ipsec ikev2 ipsec-proposal AES-GCM
protocol esp encryption aes-256
protocol esp integrity sha-256
Note: GCM ciphers are inherently authenticated, thus the configured
integrity algorithm is ignored for these ciphers and the null cipher is
recommended. When changing to a non-GCM cipher, first configure a valid
integrity algorithm as well.
For all available options, see Cisco ASA Series Command Reference .
For LAN-to-LAN IPsec IKEv2 VPN connections, match the configuration on the
remote side accordingly to ensure that the VPN tunnels keep working.
To completely close the attack vector, force all existing IPsec IKEv2 VPN
connections to log off and then re-establish their session using the new
ciphers as follows:
firewall# vpn-sessiondb logoff protocol ikev2
Do you want to logoff the VPN session(s) [confirm]
INFO: Number of sessions with protocol "IKEv2" logged off : 0
Note: Using this command will force all existing IPsec IKEv2 VPN tunnels to
be torn down. This will cause intermittent packet loss across the affected
VPN tunnels until those tunnels are re-established.
While this workaround 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 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.
Fixed Releases
In the following table(s), the left column lists Cisco software releases.
The center column indicates whether a release is affected by the
vulnerability described in this advisory and the first release that
includes the fix for this vulnerability. The right column indicates whether
a release is affected by any of the Critical or High SIR vulnerabilities
described in this bundle and which release includes fixes for those
vulnerabilities.
ASA Software
Cisco ASA First Fixed Release First Fixed Release for All
Software for This Vulnerabilities Described in the Bundle
Release Vulnerability of Advisories
9.7 and Not vulnerable. Migrate to a fixed release.
earlier ^1
9.8 Not vulnerable. Migrate to a fixed release.
9.9 ^1 Not vulnerable. Migrate to a fixed release.
9.10 ^1 Not vulnerable. Migrate to a fixed release.
9.12 9.12.4.37 9.12.4.38
9.13 ^1 Migrate to a fixed Migrate to a fixed release.
release.
9.14 9.14.3.13 9.14.4
9.15 9.15.1.21 9.15.1.21
9.16 9.16.2.7 9.16.2.14
9.17 Not vulnerable. 9.17.1.7
1. Cisco ASA Software releases 9.7 and earlier as well as releases 9.9,
9.10, and 9.13 have reached end of software maintenance . Customers are
advised to migrate to a supported release that includes the fix for this
vulnerability.
FTD Software
Cisco First Fixed Release for This Vulnerability First Fixed
FTD Release for All
Software Vulnerabilities
Release Described in the
Bundle of
Advisories
6.2.2
and Not vulnerable. Migrate to a
earlier fixed release.
^1
6.2.3 Not vulnerable. Migrate to a
fixed release.
6.3.0 ^1 Not vulnerable. Migrate to a
fixed release.
6.4.0 6.4.0.13 6.4.0.15 (May
2022)
6.5.0 ^1 Migrate to a fixed release. Migrate to a
fixed release.
6.6.0 6.6.5.1 6.6.5.2
Cisco_FTD_Hotfix_AA-6.7.0.4-2.sh.REL.tar
6.7.0 Cisco_FTD_SSP_FP1K_Hotfix_AA-6.7.0.4-2.sh.REL.tar Migrate to a
Cisco_FTD_SSP_FP2K_Hotfix_AA-6.7.0.4-2.sh.REL.tar fixed release.
Cisco_FTD_SSP_Hotfix_AA-6.7.0.4-2.sh.REL.tar
7.0.0 7.0.2 (May 2022) 7.0.2 (May 2022)
7.1.0 Not vulnerable. 7.1.0.1
1. Cisco FMC and FTD Software releases 6.2.2 and earlier, as well as
releases 6.3.0 and 6.5.0, have reached end of software maintenance .
Customers are advised to migrate to a supported release that includes the
fix for these vulnerabilities.
For instructions on upgrading your FTD device, see Cisco Firepower
Management Center Upgrade Guide .
The Cisco Product Security Incident Response Team (PSIRT) validates only
the affected and fixed release information that is documented in this
advisory.
Exploitation and Public Announcements
o The Cisco 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.
Related to This Advisory
o Cisco Event Response: April 2022 Cisco ASA, FMC, and FTD Software Security
Advisory Bundled Publication
URL
o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-ipsec-mitm-CKnLr4
Revision History
o +----------+---------------------------+----------+--------+--------------+
| Version | Description | Section | Status | Date |
+----------+---------------------------+----------+--------+--------------+
| 1.0 | Initial public release. | - | Final | 2022-APR-27 |
+----------+---------------------------+----------+--------+--------------+
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