|2017-04-04||PLC||Schneider Electric Unity||Eran Goldstein of CRITIFENCE reported the identified vulnerabilities.||N/A||CVE-2017-6034||N/A||N/A||N/A|
# MODBUS UMAS AUTHENTICATION BYPASS
### VULNERABLE VENDOR
### VULNERABLE PRODUCT
Modicon Modbus UMAS Protocol
### AFFECTED PRODUCTS
The following versions of Schneider Electric’s Modicon Modbus protocol, which can be used with the Modicon family of PLCs, are affected:
Modicon Modbus protocol, all versions.
All Unity series PLCs.
All Unity OS from version 2.6 and later.
Successful exploitation of these vulnerabilities may allow an unauthorized remote attacker to capture and replay sensitive commands to PLCs on a network using the Modicon Modbus protocol.
### VULNERABILITY OVERVIEW
AUTHENTICATION BYPASS BY CAPTURE-REPLAY CWE-294
Sensitive information is transmitted in cleartext in the Modicon Modbus protocol, which may allow an attacker to replay the following commands: run, stop, upload, and download.
CVE-2017-6034 has been assigned to this vulnerability. A CVSS v3 base score of 10.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H)
Critical Infrastructure Sector(s): Critical Manufacturing, Chemicals, Power and Energy, Oil and Gas, Food and Agriculture, Water Systems and Waste facilities.
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Paris, France
Schneider Electric has reported that they have introduced compensating controls to limit the exploitability of the identified vulnerabilities in many of PLCs in the Modicon family; however, Schneider Electric recommends that users apply security measures to improve resiliency.
Schneider Electric’s Momentum M1E controllers (all versions of model 171CBU98090 and all versions of model 171CBU98091) do not have built-in compensating controls to limit the exploitability of the identified vulnerabilities and Schneider Electric instructs users to take the following defensive measures:
1. Protect access to M1E controllers by a firewall blocking all remote/external access to Port 502.
Schneider Electric reports that Modicon M340, M580, Premium and Quantum users should take one or more of the following defensive measures:
1. Enable protection based on an authentication to connect to PLC. This method relies on a feature named Application Password. Once enabled, password-based authentication is required whenever a user connects to change their application program;
2. Enable protection relying on an input (M340, Premium, Quantum) or a key switch in the front panel (Quantum) to reject remote connection or run/stop commands; and
3. Enable the “Access Control List protection”, where users are able to configure the restricted IP addresses that are pre-authorized to control the PLC.
For additional information, Schneider Electric has released a Cybersecurity Notification, which is available at the following location: