CVE-2021-34793 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
Remote attackers can cause network disruption by poisoning MAC address tables on Cisco ASA or FTD devices operating in transparent mode.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-34793?
CVE-2021-34793 is a high-severity denial of service vulnerability in Cisco Adaptive Security Appliance, published on 27 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-924
Which versions are affected by CVE-2021-34793?
It affects 11 products.
Products include Cisco Adaptive Security Appliance, Cisco Adaptive Security Appliance Software, Cisco Asa 5505 Firmware, Cisco Asa 5512-X Firmware, Cisco Asa 5515-X Firmware, Cisco Asa 5525-X Firmware and 5 more.
How do I fix CVE-2021-34793?
No fix has been published for CVE-2021-34793 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-34793 being exploited?
There is no known exploitation of CVE-2021-34793 in the wild and no public exploit code.
Other vulnerabilities in Cisco Adaptive Security Appliance
- CVE-2021-1573 Denial of service in Cisco Adaptive Security Appliance Software
- CVE-2021-40117 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
- CVE-2021-40118 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
- CVE-2020-3304 Denial of service in Cisco Adaptive Security Appliance (ASA) Software
- CVE-2020-3436 File upload in Cisco Adaptive Security Appliance (ASA) Software
Sources
Also known as GHSA-jjpm-mxjp-g6mw.