Headline
CVE-2021-40118: Cisco Security Advisory: Cisco Adaptive Security Appliance Software and Firepower Threat Defense Software Web Services Denial of Service Vulnerabilities
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
Cisco has released free software updates that address the vulnerabilities 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 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 columns indicate whether a release is affected by the vulnerabilities described in this advisory and the first release that includes the fix for these vulnerabilities. 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 Major Release
First Fixed Release for CVE-2021-1573
First Fixed Release for CVE-2021-34704
First Fixed Release for CVE-2021-40118
First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
9.7 and earlier1
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
9.8
9.8.4.40
Not vulnerable.
9.8.4.40
9.8.4.40
9.91
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
9.101
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
9.12
9.12.4.26
Not vulnerable.
9.12.4.29
9.12.4.29
9.131
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
9.14
9.14.3
Not vulnerable.
9.14.3.9
9.14.3.9
9.15
9.15.1.17
9.15.1.17
9.15.1.17
9.15.1.17
9.16
9.16.1.28
9.16.2
9.16.2.3
9.16.2.3
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 these vulnerabilities.
FTD Software
Cisco FTD Major Release
First Fixed Release for CVE-2021-1573
First Fixed Release for CVE-2021-34704
First Fixed Release for CVE-2021-40118
First Fixed Release for All Vulnerabilities Described in the Bundle of Advisories
6.2.2 and earlier1
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
6.2.3
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
6.3.01
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
6.4.0
6.4.0.13 (Nov 2021)
Not vulnerable.
6.4.0.13 (Nov 2021)
6.4.0.13 (Nov 2021)
6.5.01
Migrate to a fixed release.
Not vulnerable.
Migrate to a fixed release.
Migrate to a fixed release.
6.6.0
6.6.5
Not vulnerable.
6.6.5
6.6.5.1 (Nov 2021)
6.7.0
6.7.0.3 (Jan 2022)
6.7.0.3 (Jan 2022)
6.7.0.3 (Jan 2022)
6.7.0.3 (Jan 2022)
7.0.0
7.0.1
7.0.1
7.0.1
7.0.1
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.