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Advisory (ICSA-16-357-02)

WAGO Ethernet Web-based Management Authentication Bypass Vulnerability

Original release date: December 22, 2016

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OVERVIEW

Independent researcher Maxim Rupp has identified an authentication bypass vulnerability in WAGO’s Ethernet Web-based Management products. WAGO has produced firmware and workarounds to mitigate this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

WAGO reports that the vulnerability affects the following products:

  • WAGO 750-8202/PFC200 prior to FW04 (released August 2015),
  • WAGO 750-881 prior to FW09 (released August 2016), and
  • WAGO 0758-0874-0000-0111

IMPACT

An attacker who exploits this vulnerability could be able to view and edit settings without authenticating.

Impact to individual organizations depends on many factors that are unique to each organization. NCCIC/ICS-CERT recommends that organizations evaluate the impact of this vulnerability based on their operational environment, architecture, and product implementation.

BACKGROUND

WAGO is an international company based in Germany. They operate production facilities in Germany, Switzerland, Poland, China, and India. WAGO maintains offices worldwide.

According to WAGO, its products are deployed across several sectors including Commercial Facilities, Critical Manufacturing, Energy, and Transportation Systems. WAGO estimates that these products are used worldwide.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

AUTHENTICATION BYPASS ISSUEa

By accessing a specific uniform resource locator (URL) on the web server, a malicious user is able to edit and to view settings without authenticating.

CVE-2016-9362b has been assigned to this vulnerability. A CVSS v3 base score of 9.1 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).c

VULNERABILITY DETAILS

EXPLOITABILITY

This vulnerability could be exploited remotely.

EXISTENCE OF EXPLOIT

No known public exploits specifically target this vulnerability.

DIFFICULTY

An attacker with a low skill would be able to exploit this vulnerability.

MITIGATION

WAGO recommends the following use conditions for Ethernet devices:

If not otherwise specified, Ethernet devices are intended for use on local networks. Users should note the following when using Ethernet devices:

  • Do not connect control components and control networks to an open network such as the Internet or an office network. WAGO recommends putting control components and control networks behind a firewall.
  • Limit physical and electronic access to all automation components to authorized personnel only.
  • Change the default passwords before first use. This will reduce the risk of unauthorized access to systems.
  • Regularly change passwords. This will reduce the risk of unauthorized access to systems.
  • If remote access to control components and control networks is required, use a Virtual Private Network (VPN).
  • Regularly perform threat analyses. Check whether the measures taken meet company security requirements.
  • Use “defense-in-depth” mechanisms in the system’s security configuration to restrict the access to and control of individual products and networks.

ICS-CERT recommends that 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.

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 at: http://ics-cert.us-cert.gov/content/recommended-practices. 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 (http://ics-cert.us-cert.gov/).

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.


Contact Information

For any questions related to this report, please contact ICS-CERT at:

Email: ics-cert@hq.dhs.gov
Toll Free: 1-877-776-7585
International Callers: (208) 526-0900

For industrial control systems security information and incident reporting: http://ics-cert.us-cert.gov

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