Improper Enforcement of Message Integrity During Transmission in a Communication Channel in Cisco Systems, Inc products - CVE-2021-34793
Published: October 28, 2021
Vulnerability identifier: #VU57753
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-34793
CWE-ID: CWE-924
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists in the TCP Normalizer when handling certain TCP segments. A remote attacker can send a specially crafted TCP segment through an affected device and poison MAC address tables.
Successful exploitation of the vulnerability may allow an attacker to perform a denial of service attack but requires the affected device to be operating in transparent mode.
Affected software
ASA 5500-X Series Firewalls
Cisco Firewall Threat Defense (FTD)
Cisco Adaptive Security Appliance (ASA)
Cisco Firewall Threat Defense (FTD)
Cisco Adaptive Security Appliance (ASA)
How to mitigate CVE-2021-34793
Install update from vendor's website.
Cisco Firewall Threat Defense (FTD) - addressed in versions 6.4.0.13, 6.6.5, 6.7.0.2
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.8.4.40, 9.12.4.24, 9.14.2.15, 9.15.1.15
Cisco Adaptive Security Appliance (ASA) - addressed in versions 9.8.4.40, 9.12.4.24, 9.14.2.15, 9.15.1.15