Schneider Electric Modicon M221 PLCs and SoMachine Basic

CVSS v3 10.0

**ATTENTION:**Remotely exploitable/low skill level to exploit. Public exploits are available.

Vendor: Schneider Electric

Equipment: Modicon M221 PLCs and SoMachine Basic

Vulnerability: Use of Hard-Coded Cryptographic Key, Protection Mechanism Failure

AFFECTED PRODUCTS

Schneider Electric reports that these vulnerabilities affect the following PLCs and tools for configuring and developing automation machinery:

• Modicon M221 PLC, firmware versions up to v1.5.0.1, and
• SoMachine Basic, software versions up to v1.5

IMPACT

One vulnerability may allow an attacker to extract a protected project file from the controller to obtain sensitive project information. The second vulnerability may allow a user with access to a protected project file to decrypt it in order to obtain sensitive information without authorization.

MITIGATION

Schneider Electric recommends that users store project files in secure, access-restricted locations and encrypt project files with reputable third party file encryption tools. A fix to enhance the SoMachine Basic encryption mechanism will be released on June 15, 2017.

Schneider Electric’s security notice SEVD-2017-097-01 is available at the following location:

<http://www.schneider-electric.com/en/download/document/SEVD-2017-097-01/&gt;

Schneider Electric recommends that users implement the following mitigations until an enhanced encryption mechanism is released on June 15, 2017:

• Activate Application Protection with a blank password within Modicon M221 applications, as described in section “Password Protecting an Application” of SoMachine Basic online help. This will disable the application upload features of the M221.
• Protect access to controllers using a firewall and blocking all remote/external access to Port 502/TCP.

Schneider Electric’s security notice SEVD-2017-097-02 is available at the following location:

<http://www.schneider-electric.com/en/download/document/SEVD-2017-097-02/&gt;

NCCIC/ICS-CERT recommends that users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Specifically, users should:

• Minimize network exposure for all control system devices and/or systems, and ensure that they are not accessible from the Internet.
• Locate control system networks and remote devices behind firewalls, and isolate them from the business network.
• When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize that VPN is only as secure as the connected devices.

ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly available in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies, that is available for download from the ICS-CERT web site.

Organizations observing any suspected malicious activity should follow their established internal procedures and report their findings to ICS-CERT for tracking and correlation against other incidents.

VULNERABILITY OVERVIEW

USE OF HARD-CODED CRYPTOGRAPHIC KEY CWE-321

Project files, including user-defined project passwords, are encrypted with a hardcoded password.

CVE-2017-7574 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:L).

PROTECTION MECHANISM FAILURE CWE-693

An attacker can send a specifically crafted command via Modbus over TCP port 502 to the logic controller to discover an application protection password.

CVE-2017-7575 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:L).

RESEARCHER

Simon Heming, Maik Brüggemann, Hendrik Schwartke, and Ralf Spenneberg of Open Source Security discovered these vulnerabilities.

BACKGROUND

Critical Infrastructure Sector: Commercial Facilities

**Countries/Areas Deployed:**Worldwide

Company Headquarters Location: France