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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. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vpndtls-dos-TunzLEV The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
Please refer to the Security Advisory.
Please refer to the Security Advisory.
Please refer to the Security Advisory. Cisco would like to thank Fabio Streun of ETH Zurich for reporting this vulnerability.
The Cisco PSIRT has assigned this bug the following CVSS version 3 score. The Base CVSS score as of the time of evaluation is 5.8: https://tools.cisco.com/security/center/cvssCalculator.x?vector=CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L CVE ID CVE-2022-20795 has been assigned to document this issue. Information about Fixed, Vulnerable, and Nonvulnerable releases--as well as information about fixed release availability--is not maintained by Cisco PSIRT. Please refer to the appropriate fields in this bug. If you require additional help to obtain this information, please open a support case with your support organization. Additional information on Cisco's security vulnerability policy can be found at the following URL: https://tools.cisco.com/security/center/resources/security_vulnerability_policy.html