First published: Wed Oct 27 2021(Updated: )
A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption. 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://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asa-ftd-dos-JxYWMJyL This advisory is part of the October 2021 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: October 2021 Cisco ASA, FMC, and FTD Software Security Advisory Bundled Publication.
Credit: This vulnerability was found during the resolution a Cisco TAC support case
Affected Software | Affected Version | How to fix |
---|---|---|
Cisco ASA | =9.15<9.15.1.15>=9.13<=9.14<9.14.2.15>=9.9=9.10<=9.12<9.12.4.24>=9.7 and earlier<=9.8<9.8.4.40 | 9.15.1.15 9.14.2.15 9.12.4.24 9.8.4.40 |
Cisco FTD Software Releases | >=6.2.2 and earlier=6.2.3=6.3.0<=6.4.0<6.4.0.13 (Nov 2021) | 6.4.0.13 (Nov 2021) |
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The vulnerability ID is cisco-sa-asa-ftd-dos-JxYWMJyL.
The severity of this vulnerability is high with a score of 8.6.
This vulnerability allows an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability.
The affected software includes Cisco ASA Software versions 9.15, 9.14, 9.12.4.24, and 9.8.4.40, as well as Cisco FTD Software versions 6.2.2 and earlier, 6.2.3, 6.3.0, and up to 6.4.0.13 (Nov 2021).
To fix this vulnerability, apply the recommended patches and updates provided by Cisco. Refer to the Cisco Security Advisory for specific remediation instructions.