QID 317160

Date Published: 2022-04-26

QID 317160: Cisco Adaptive Security Appliance (ASA) AnyConnect Secure Sockets Layer (SSL) Virtual Private Network (VPN) Denial of Service (DoS) Vulnerability (cisco-sa-vpndtls-dos-TunzLEV)

A vulnerability in the implementation of the Datagram TLS (DTLS) protocol in Cisco Adaptive Security Appliance (ASA) Software
could allow an unauthenticated,
remote attacker to cause high CPU utilization, resulting in a denial of
service (DoS) condition.

Affected Products
Cisco devices if they were running one of the following releases of Cisco software and were configured for termination of DTLS
tunnels for AnyConnect SSL VPN connections:
ASA Software Release 9.16.3 or earlier
ASA Software Release 9.17.1.9 or earlier
Note: SSL VPN is disabled by default. When SSL VPN is enabled on an interface, DTLS is enabled by default.

QID Detection Logic (Authenticated):
The check matches Cisco ASA OS version retrieved via Unix Auth using "version" command.

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.

  • CVSS V3 rated as High - 7.5 severity.
  • CVSS V2 rated as Medium - 5 severity.
    • Solution

    Customers are advised to refer to cisco-sa-vpndtls-dos-TunzLEV for more information.

    Vendor References

    CVEs related to QID 317160

    CVE-2022-20795 |
    Software Advisories
    Advisory ID Software Component Link
    cisco-sa-vpndtls-dos-TunzLEV URL Logo tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vpndtls-dos-TunzLEV
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