A vulnerability in the Internet Key Exchange version 1 (IKEv1) feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition.
The vulnerability is due to improper management of system memory. An attacker could exploit this vulnerability by sending malicious IKEv1 traffic to an affected device. The attacker does not need valid credentials to authenticate the VPN session, nor does the attacker's source address need to match a peer statement in the crypto map applied to the ingress interface of the affected device. An exploit could allow the attacker to exhaust system memory resources, leading to a reload of an affected device.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication, which includes 10 Cisco Security Advisories that describe 18 vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: October 2019 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.
This advisory is available at the following link:
This vulnerability affects the following Cisco products when running a vulnerable release of Cisco ASA Software or Cisco FTD Software on interfaces that have the IKEv1 protocol enabled for LAN-to-LAN or Remote Access IPsec VPN connections:
- Adaptive Security Virtual Appliance (ASAv)
- Firepower 2100 Series Appliances
- Firepower Threat Defense Virtual (FTDv)
The IKEv1 protocol is disabled in Cisco ASA Software and FTD Software by default.
Note: IKE version 2 (IKEv2)-based VPN connections are not affected by this vulnerability.
For information about which Cisco ASA Software and FTD Software releases are vulnerable, see the Fixed Software section of this advisory.
Determine Whether the IKEv1 Protocol Is Configured
To enable the IKEv1 protocol for LAN-to-LAN or Remote Access IPsec VPN connections, two conditions need to be true:
- An Internet Security Association and Key Management Protocol (ISAKMP) policy for IKEv1 needs to be configured.
- IKEv1 needs to be enabled on at least one interface.
Administrators can use the show running-config crypto ikev1 command to determine whether an ISAKMP policy for IKEv1 is configured and whether IKEv1 is enabled on at least one interface. The following example shows the output of the show running-config crypto ikev1 command on a device that has ISAKMP policy 1 configured for IKEv1 and that has IKEv1 enabled on the outside interface:
ciscoasa# show running-config crypto ikev1
crypto ikev1 enable outside
crypto ikev1 policy 1
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)
- ASA 1000V Cloud Firewall
- ASA 5505 Series Adaptive Security Appliances
- ASA 5500-X Series Firewalls
- ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
- Firepower 1000 Series
- Firepower 4100 Series
- Firepower 9300 ASA Security Module
- Firepower 9300 Security Appliances
- Firepower Management Center (FMC)
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:
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 and Alerts 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:
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 ReleasesIn the following tables, the left column lists releases of Cisco ASA Software, Cisco FMC Software, or Cisco FTD Software. 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 vulnerabilities described in this bundle and which release includes fixes for those vulnerabilities.
Cisco ASA Software
Cisco ASA Software Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories Earlier than 9.41
Migrate to a fixed release.
9.41 Not vulnerable.
Migrate to a fixed release. 9.51 Not vulnerable.
Migrate to a fixed release. 9.6 Not vulnerable.
188.8.131.52 9.71 Migrate to a fixed release. Migrate to a fixed release. 9.8 184.108.40.206 220.127.116.11 9.9 18.104.22.168 Migrate to a fixed release. 9.10 22.214.171.124 126.96.36.199 9.12 9.12.2 188.8.131.52 9.13 Not vulnerable. Not vulnerable.
1. Cisco ASA Software releases 9.5 and earlier, as well as Release 9.7, have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.
Cisco FTD Software
Cisco FTD Software Release First Fixed Release for This Vulnerability First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories Earlier than 6.1.01 Not vulnerable.
Migrate to a fixed release. 6.1.0 Not vulnerable.
Migrate to a fixed release. 6.2.0 Migrate to a fixed release. Migrate to a fixed release. 6.2.1 Migrate to a fixed release. Migrate to a fixed release. 6.2.2 Migrate to a fixed release. Migrate to a fixed release. 6.2.3 184.108.40.206 Migrate to a fixed release. 6.3.0 220.127.116.11 18.104.22.168
6.4.0 Not vulnerable.
22.214.171.124 6.5.0 Not vulnerable. Not vulnerable.
1. Cisco FMC and FTD Software releases 6.0.1 and earlier have reached end of software maintenance. Customers are advised to migrate to a supported release that includes the fix for this vulnerability.
To upgrade to a fixed release of Cisco FTD Software, customers can do one of the following:
- For devices that are managed by using Cisco Firepower Management Center (FMC), use the FMC interface to install the upgrade. After installation is complete, reapply the access control policy.
- For devices that are managed by using Cisco Firepower Device Manager (FDM), use the FDM interface to install the upgrade. After installation is complete, reapply the access control policy.
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 the resolution of a Cisco TAC support case.
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 1.0 Initial public release. — Final 2019-October-02
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