CVE-2024-20481 Cisco ASA and FTD Denial-of-Service
Unauthenticated remote attackers can cause a denial of service in Cisco ASA and FTD VPN services by exhausting resources through excessive authentication requests.
- Exploited in the wild
- Since 24 Oct 2024
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-20481?
CVE-2024-20481 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 23 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service. This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authentication requests to an affected device. A successful exploit could allow the attacker to exhaust resources, resulting in a DoS of the RAVPN service on the affected device. Depending on the impact of the attack, a reload of the device may be required to restore the RAVPN service. Services that are not related to VPN are not affected. Cisco Talos discussed these attacks in the blog post Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials.
Weakness: CWE-772
Which versions are affected by CVE-2024-20481?
It affects 2 products.
Products include Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.
How do I fix CVE-2024-20481?
No fix has been published for CVE-2024-20481 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 14 Nov 2024.
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-2024-20481 being exploited?
Yes. Attackers have exploited CVE-2024-20481 in the wild since at least 24 Oct 2024.
Other vulnerabilities in Cisco Adaptive Security Appliance Software
- CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow
- CVE-2016-6366 Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow
- CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection
- CVE-2024-20353 Cisco ASA and FTD Denial of Service
- CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution
All Cisco Adaptive Security Appliance Software vulnerabilities
Sources
Also known as GHSA-cp3f-3wc5-j85w.