A vulnerability has been discovered in the ingress flow creation functionality of the Cisco Adaptive Security Appliance (ASA). This vulnerability could potentially allow an unauthenticated, remote attacker to send a steady stream of malicious IP packets to DoS (denial of service) and infect the system by maxing out CPU usage. A DoS of this type could cripple network traffic that is being routed through the device, and would directly impact the availability of business resources. Cisco has not publicly released details regarding what traffic to send to initiate the DoS.
This vulnerability affects Cisco Adaptive Security Appliance (ASA) and Firepower Threat Defense (FTD) Software that is running on the following Cisco products:
- 3000 Series Industrial Security Appliances (ISA)
- ASA 5500 Series Adaptive Security Appliances
- ASA 5500-X Series Next-Generation Firewalls
- ASA Services Module for Cisco Catalyst 6500 Series Switches and Cisco 7600 Series Routers
- Adaptive Security Virtual Appliances (ASAv)
- Firepower 2100 Series Security Appliances
- Firepower 4110 Security Appliances
- Firepower 9300 ASA Security Modules.
Proficio Threat Intelligence Recommendations:
- Workaround: The ASA and FTD configuration commands, set connection per-client-embryonic-max (TCP) and set connection per-client-max (TCP, UDP, and Stream Control Transmission Protocol {SCTP}), can be configured to limit the number of connection requests allowed. Setting the vendor recommended configuration parameters can reduce the number of connections and greatly reduce the impact of the DoS attack
- Permanent Fix: Customers should upgrade to an appropriate firmware release as indicated in the link below
Firmware Checker – Click Here
