Summary
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.
Impact
If an unauthorized user manages to get access as described above, he gains full access to the device configuration.
Affected Product(s)
| Model no. | Product name | Affected versions |
|---|---|---|
| FL NAT SMCS 8TX | Firmware all versions | |
| FL NAT SMN 8TX | Firmware all versions | |
| FL NAT SMN 8TX-M | Firmware all versions | |
| FL NAT SMN 8TX-M-DMG | Firmware all versions |
Vulnerabilities
Expand / Collapse allAn 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.
Mitigation
Customers using Phoenix Contact FL NAT SMx devices are recommended to operate the devices in closed networks or protected with a suitable firewall.\
For detailed information on our recommendations for measures to protect network-capable devices, please refer to the application note:
To protect the device from an attacker who has gained access to the closed network, or if there is a possibility that multiple users might share a VPN connection with a single endpoint IP, it might be considered to:
log off from the WEB-UI immediately after administration\
disable the WEB-UI and use configuration access via SNMP instead
Revision History
| Version | Date | Summary |
|---|---|---|
| 1 | 03/25/2019 12:40 | Initial revision. |
| 2 | 11/06/2024 12:27 | Fix: correct certvde domain, added alias, added self-reference |
| 3 | 05/14/2025 14:28 | Fix: version term, added distribution |