Siemens SIMATIC RFID

1. EXECUTIVE SUMMARY

• CVSS v3 7.3 *ATTENTION: Exploitable remotely/low attack complexity
• **Vendor:**Siemens
• **Equipment:**SIMATIC RFID terminals
• **Vulnerability:**Out-of-bounds Write

2. RISK EVALUATION

Successful exploitation of this vulnerability could allow an attacker to remotely execute code.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of SIMATIC RFID are affected:

• SIMATIC RF350M: All versions
• SIMATIC RF650M: All versions

3.2 VULNERABILITY OVERVIEW

3.2.1 OUT-OF-BOUNDS WRITE CWE-787

In FreeBSD 12.1-STABLE before r365010, 11.4-STABLE before r365011, 12.1-RELEASE before p9, 11.4-RELEASE before p3, and 11.3-RELEASE before p13, dhclient(8) fails to handle certain malformed input related to handling of DHCP option 119, resulting a heap overflow. The heap overflow could be exploited to achieve remote code execution. The affected process runs with reduced privileges in a Capsicum sandbox, limiting the immediate impact of an exploit.

CVE-2020-7461 has been assigned to this vulnerability. A CVSS v3 base score of 7.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L).

3.3 BACKGROUND

• **CRITICAL INFRASTRUCTURE SECTORS:**Multiple
• **COUNTRIES/AREAS DEPLOYED:**Worldwide
• **COMPANY HEADQUARTERS LOCATION:**Germany

3.4 RESEARCHER

Siemens reported this vulnerability to CISA.

4. MITIGATIONS

Siemens has identified the following specific workarounds and mitigations users can apply to reduce the risk:

• Use trusted DNS servers in internal network and restrict DNS traffic to this network only through firewalls.
• Protect network access to affected devices.

As a general security measure, Siemens strongly recommends users protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends users configure the environment according to Siemens operational guidelines for industrial security and follow the recommendations in the product manuals.

Additional information on industrial security by Siemens can be found at: https://www.siemens.com/industrialsecurity

For more information about this issue, please see Siemens Security Advisory SSA-288459

CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability. 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 VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as its connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on us-cert.cisa.gov. 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 on the ICS webpage on us-cert.cisa.gov in the Technical Information Paper, ICS-TIP-12-146-01B–Targeted Cyber Intrusion Detection and Mitigation Strategies.

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

No known public exploits specifically target this vulnerability.