An issue was discovered on PHOENIX CONTACT FL NAT SMCS 8TX, FL NAT SMN 8TX, FL NAT SMN 8TX-M, and FL NAT SMN 8TX-M-DMG devices. There is unauthorized access to the WEB-UI by attackers arriving from the same source IP address as an authenticated user, because this IP address is used as a session identifier.

An issue was discovered on PHOENIX CONTACT FL NAT SMCS 8TX, FL NAT SMN 8TX, FL NAT SMN 8TX-M, and FL NAT SMN 8TX-M-DMG devices. There is unauthorized access to the WEB-UI by attackers arriving from the same source IP address as an authenticated user, because this IP address is used as a session identifier.

An unauthorized user can access the web interface using an authorized IP address, which may allow full access to the device configuration. This attack is only possible if an authorized session is still active on the system.CVE-2019-9744 has been assigned to this vulnerability. A CVSS v3 base score of 8.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

After login the source IP is used as the session identifier, so that users sharing the same source IP are able to gain full authenticated access to the WEB-UI.

The access attempt will only be successful if the former authorized session has not been terminated by the authorized user or by session timeout.