Cisco Duo Two-Factor Authentication for macOS Authentication Bypass Vulnerability
cisco-sa-duo-mac-bypass-OyZpVPnx · Medium · Published · Updated
A vulnerability in Cisco Duo Two-Factor Authentication for macOS could allow an authenticated, physical attacker to bypass secondary authentication and access an affected macOS device. This vulnerability is due to the incorrect handling of responses from Cisco Duo when the application is configured to fail open. An attacker with primary user credentials could exploit this vulnerability by attempting to authenticate to an affected device. A successful exploit could allow the attacker to access the affected device without valid permission. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-duo-mac-bypass-OyZpVPnx
There are no workarounds that address this vulnerability.
However, to mitigate this vulnerability, administrators may consider disabling fail open, which will prevent users from gaining access without network connectivity. For more information, see the Offline Access https://duo.com/docs/macos#offline-access section of the Duo Two-Factor Authentication for macOS configuration guide.
While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.