CVE-2022-20795
MediumCVSS 5.8Exploitation Probability (EPSS)
Low risk49th percentile - higher than 49% of all known CVEs
Summary
A vulnerability in the Datagram TLS (DTLS) protocol implementation in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause high CPU utilization, resulting in a denial of service (DoS) condition. This is due to suboptimal processing when establishing a DTLS tunnel as part of an AnyConnect SSL VPN connection. An attacker could exploit this by sending a steady stream of crafted DTLS traffic, exhausting resources on the device.
Risk Assessment
The risk is that an attacker can exhaust VPN device resources, disrupting existing DTLS tunnels and preventing new ones, causing a DoS.
Recommendation
Apply Cisco updates for ASA and FTD. Monitor DTLS traffic and consider limiting concurrent VPN connections.
Original NVD description (English source)
A vulnerability in the implementation of the Datagram TLS (DTLS) protocol in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause high CPU utilization, resulting in a denial of service (DoS) condition. This vulnerability is due to suboptimal processing that occurs when establishing a DTLS tunnel as part of an AnyConnect SSL VPN connection. An attacker could exploit this vulnerability by sending a steady stream of crafted DTLS traffic to an affected device. A successful exploit could allow the attacker to exhaust resources on the affected VPN headend device. This could cause existing DTLS tunnels to stop passing traffic and prevent new DTLS tunnels from establishing, resulting in a DoS condition. Note: When the attack traffic stops, the device recovers gracefully.