Headline
CVE-2019-15256: Cisco Security Advisory: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software IKEv1 Denial of Service Vulnerability
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 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.htmlAdditionally, 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:
https://www.cisco.com/c/en/us/support/web/tsd-cisco-worldwide-contacts.htmlCustomers 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 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
Not vulnerable.
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.
9.6.4.34
9.71
Migrate to a fixed release.
Migrate to a fixed release.
9.8
9.8.3.26
9.8.4.10
9.9
9.9.2.47
Migrate to a fixed release.
9.10
9.10.1.17
9.10.1.30
9.12
9.12.2
9.12.2.5
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
6.2.3.11
Migrate to a fixed release.
6.3.0
6.3.0.2
6.4.0.4
6.4.0
Not vulnerable.
6.4.0.4
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.