1. EXECUTIVE SUMMARY

  • CVSS v3 9.8
  • ATTENTION: Exploitable remotely/low skill level to exploit
  • Vendor: Weidmueller
  • Equipment: Industrial Ethernet Switches
  • Vulnerabilities: Improper Restriction of Excessive Authentication Attempts, Uncontrolled Resource Consumption, Missing Encryption of Sensitive Data, Unprotected Storage of Credentials, and Predictable from Observable State

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow a remote attacker to gain unauthorized access to the device, affecting the confidentiality, integrity, and availability of the device the attacker is targeting.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of industrial Ethernet switches are affected:

  • IE-SW-VL05M-5TX firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL05MT-5TX firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL05M-3TX-2SC firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL05MT-3TX-2SC firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL05M-3TX-2ST firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL05MT-3TX-2ST firmware v3.6.6 Build 16102415 and prior
  • IE-SW-VL08MT-8TX firmware v3.5.2 Build 16102415 and prior
  • IE-SW-VL08MT-5TX-3SC firmware v3.5.2 Build 16102415 and prior
  • IE-SW-VL08MT-5TX-1SC-2SCS firmware v3.5.2 Build 16102415 and prior
  • IE-SW-VL08MT-6TX-2ST firmware v3.5.2 Build 16102415 and prior
  • IE-SW-VL08MT-6TX-2SC firmware v3.5.2 Build 16102415 and prior
  • IE-SW-VL08MT-6TX-2SCS firmware v3.5.2 Build 16102415 and prior
  • IE-SW-PL08M-8TX firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08MT-8TX firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08M-6TX-2SC firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08MT-6TX-2SC firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08M-6TX-2ST firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08MT-6TX-2ST firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08M-6TX-2SCS firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL08MT-6TX-2SCS firmware v3.3.8 Build 16102416 and prior
  • IE-SW-PL10M-3GT-7TX firmware v3.3.16 Build 16102416 and prior
  • IE-SW-PL10MT-3GT-7TX firmware v3.3.16 Build 16102416 and prior
  • IE-SW-PL10M-1GT-2GS-7TX firmware v3.3.16 Build 16102416 and prior
  • IE-SW-PL10MT-1GT-2GS-7TX firmware v3.3.16 Build 16102416 and prior
  • IE-SW-PL16M-16TX firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL16MT-16TX firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL16M-14TX-2SC firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL16MT-14TX-2SC firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL16M-14TX-2ST firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL16MT-14TX-2ST firmware v3.4.2 Build 16102416 and prior
  • IE-SW-PL18M-2GC-16TX firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18MT-2GC-16TX firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18M-2GC14TX2SC firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18MT-2GC14TX2SC firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18M-2GC14TX2ST firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18MT-2GC14TX2ST firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18M-2GC14TX2SCS firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL18MT-2GC14TX2SCS firmware v3.4.4 Build 16102416 and prior
  • IE-SW-PL09M-5GC-4GT firmware v3.3.4 Build 16102416 and prior
  • IE-SW-PL09MT-5GC-4GT firmware v3.3.4 Build 16102416 and prior

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER RESTRICTION OF EXCESSIVE AUTHENTICATION ATTEMPTS CWE-307

The authentication mechanism has no brute-force prevention.

CVE-2019-16670 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.2    UNCONTROLLED RESOURCE CONSUMPTION CWE-400

Remote authenticated users can crash a device by using a special packet.

CVE-2019-16671 has been assigned to this vulnerability. A CVSS v3 base score of 6.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

3.2.3    MISSING ENCRYPTION OF SENSITIVE DATA CWE-311

Sensitive credentials data is transmitted in cleartext.

CVE-2019-16672 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.2.4    UNPROTECTED STORAGE OF CREDENTIALS CWE-256

Passwords are stored in cleartext and can be read by anyone with access to the device.

CVE-2019-16673 has been assigned to this vulnerability. A CVSS v3 base score of 7.5 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

3.2.5    PREDICTABLE FROM OBSERVABLE STATE CWE-341

Authentication information used in a cookie is predictable and can lead to admin password compromise when captured on the network.

CVE-2019-16674 has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

3.3 BACKGROUND

  • CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Information Technology
  • COUNTRIES/AREAS DEPLOYED: Worldwide
  • COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

CERT@VDE reported these vulnerabilities to CISA.

4. MITIGATIONS

CERT@VDE and Weidmueller report the following mitigations:

Solutions for CVE-2019-16672

Solution for vulnerabilities, valid for switch series IE-SW-VL05M and IE-SW-VL08MT

  • To avoid the vulnerabilities referred to in this section, it is necessary to install patched firmware. After installation of patched firmware, the web interface can be accessed via encrypted communication using https, and web interface access can be configured to ensure encrypted connections by selecting “https only.”
  • The respective web interface menu section for this setting can be reached via the following path: Main Menu > Basic Settings > System: Set the “Web Configuration” to “https only.”

Solution for vulnerabilities valid for switch series IE-SW-PL08M, IE-SW-PL10M, IE-SW-PL16M, IE-SW-PL18M, and IE-SW-PL09M

  • To avoid the vulnerabilities referred to in this section, installation of patched firmware is not necessary. Web interface access can be configured to ensure encrypted connections by selecting “https only.”
  • The respective web interface menu section for this setting can be reached via the following path: Main Menu > Basic Settings > System: Set the “Web Configuration” to “https only.”

Solution for CVE-2019-16670, CVE-2019-16671, CVE-2019-16673, and CVE-2019-16674

Valid for switch series IE-SW-VL05M, IE-SW-VL08MT, IE-SW-PL08M, IE-SW-PL10M, IE-SW-PL16M, IE-SW-PL18M, and IE-SW-PL09M

  • After installing the patched firmware on the switch, it is possible to disable the unencrypted search service via Weidmueller configuration software named “WM Switch Utility” for Windows OS and to enable an encrypted search service, which will be working with the new “Weidmueller Switch Configuration Utility” (available soon).
  • Both services—the encrypted and the unencrypted search service—are enabled by default. To avoid the vulnerabilities referred to in this section, the unencrypted search service should be disabled.
  • The respective web interface menu section for this setting can be reached via the following path: Main Menu > Basic Settings > Security > Management Interface: Uncheck the checkbox “Enable Search Service.”

Note: After disabling the unencrypted search service, the switches can no longer be found or configured with the current “WM Switch Utility.”

Web interface settings are not affected by this configuration.

Below are the patched versions available for the respective industrial ethernet switch model:

  • IE-SW-VL05M-5TX firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL05MT-5TX firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL05M-3TX-2SC firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL05MT-3TX-2SC firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL05M-3TX-2ST firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL05MT-3TX-2ST firmware v3.6.24 Build 19062809 and prior
  • IE-SW-VL08MT-8TX firmware v3.5.22 Build 19062810 and prior
  • IE-SW-VL08MT-5TX-3SC firmware v3.5.22 Build 19062810 and prior
  • IE-SW-VL08MT-5TX-1SC-2SCS firmware v3.5.22 Build 19062810 and prior
  • IE-SW-VL08MT-6TX-2ST firmware v3.5.22 Build 19062810 and prior
  • IE-SW-VL08MT-6TX-2SC firmware v3.5.22 Build 19062810 and prior
  • IE-SW-VL08MT-6TX-2SCS firmware v3.5.22 Build 19062810 and prior
  • IE-SW-PL08M-8TX firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08MT-8TX firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08M-6TX-2SC firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08MT-6TX-2SC firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08M-6TX-2ST firmware v3.3.16 Build 19062811and prior
  • IE-SW-PL08MT-6TX-2ST firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08M-6TX-2SCS firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL08MT-6TX-2SCS firmware v3.3.16 Build 19062811 and prior
  • IE-SW-PL10M-3GT-7TX firmware v3.3.24 Build 19062813 and prior
  • IE-SW-PL10MT-3GT-7TX firmware v3.3.24 Build 19062813 and prior
  • IE-SW-PL10M-1GT-2GS-7TX firmware v3.3.24 Build 19062813 and prior
  • IE-SW-PL10MT-1GT-2GS-7TX firmware v3.3.24 Build 19062813 and prior
  • IE-SW-PL16M-16TX firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL16MT-16TX firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL16M-14TX-2SC firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL16MT-14TX-2SC firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL16M-14TX-2ST firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL16MT-14TX-2ST firmware v3.4.18 Build 19062814 and prior
  • IE-SW-PL18M-2GC-16TX firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18MT-2GC-16TX firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18M-2GC14TX2SC firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18MT-2GC14TX2SC firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18M-2GC14TX2ST firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18MT-2GC14TX2ST firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18M-2GC14TX2SCS firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL18MT-2GC14TX2SCS firmware v3.4.30 Build 19062817 and prior
  • IE-SW-PL09M-5GC-4GT firmware v3.3.20 Build 19070111 and prior
  • IE-SW-PL09MT-5GC-4GT firmware v3.3.20 Build 19070111 and prior

For more information see the CERT@VDE advisory located at: https://cert.vde.com/en-us/advisories/vde-2019-018 or contact Weidmueller at www.weidmueller.com/service.

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 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.

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.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.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.

Source:

https://www.us-cert.gov/ics/advisories/icsa-19-339-02