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             AUSCERT External Security Bulletin Redistribution

                               ESB-2018.2099
       Advisory (ICSA-18-198-02) WAGO e!DISPLAY Web-Based-Management
                               19 July 2018

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           WAGO e!DISPLAY Web-Based-Management
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Overwrite Arbitrary Files -- Existing Account            
                   Create Arbitrary Files    -- Existing Account            
                   Cross-site Scripting      -- Remote with User Interaction
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-12981 CVE-2018-12980 CVE-2018-12979

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-18-198-02

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Advisory (ICSA-18-198-02)

WAGO e!DISPLAY Web-Based-Management

Original release date: July 17, 2018

Legal Notice

All information products included in http://ics-cert.us-cert.gov are
provided "as is" for informational purposes only. The Department of Homeland
Security (DHS) does not provide any warranties of any kind regarding any
information contained within. DHS does not endorse any commercial product or
service, referenced in this product or otherwise. Further dissemination of this
product is governed by the Traffic Light Protocol (TLP) marking in the header.
For more information about TLP, see http://www.us-cert.gov/tlp/.

1. EXECUTIVE SUMMARY

  o CVSS v3 8.0
  o ATTENTION: Exploitable remotely/Low skill level to exploit/Public exploits
    are available
  o Vendor: WAGO
  o Equipment: e!DISPLAY Web-Based-Management (WBM)
  o Vulnerabilities: Cross-site Scripting, Unrestricted Upload of File with
    Dangerous Type, and Incorrect Permissions for Critical Resource

2. RISK EVALUATION

Successful exploitation of these vulnerabilities could allow an attacker to
execute code in the context of the user, execute code within the user's
browser, place malicious files within the filesystem, and replace existing
files to allow privilege escalation.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following versions of WAGO e!DISPLAY, an HMI, running firmware FW 01 are
affected:

  o 762-3000,
  o 762-3001,
  o 762-3002, and
  o 762-3003

3.2 VULNERABILITY OVERVIEW

3.2.1    IMPROPER NEUTRALIZATION OF INPUT DURING WEB PAGE GENERATION
('CROSS-SITE SCRIPTING') CWE-79

Authenticated and unauthenticated users can send specially crafted requests to
the web server, which allows code injection within the WBM. The code will be
rendered and/or executed within the user's browser.

CVE-2018-12981 has been assigned to this vulnerability. A CVSS v3 base score of
8.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:R/S:U/C:H
/I:H/A:H).

3.2.2    UNRESTRICTED UPLOAD OF FILE WITH DANGEROUS TYPE CWE-434

This vulnerability allows an authenticated user to upload arbitrary files to
the file system with the permissions of the web server.
CVE-2018-12980 has been assigned to this vulnerability. A CVSS v3 base score of
8.0 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:L/UI:R/S:U/C:H
/I:H/A:H).

3.2.3    INCORRECT PERMISSION FOR CRITICAL RESOURCE CWE-732

Weak permissions allow an authenticated user to overwrite critical files by
abusing the unrestricted file upload in the WBM.
CVE-2018-12979 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:H/PR:N/UI:R/S:U/C:H
/I:H/A:H).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Commercial Facilities, Critical
    Manufacturing, Energy, and Transportation Systems
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: Germany

3.4 RESEARCHER

T. Weber of SEC Consult reported these vulnerabilities to CERT@VDE, who
reported them to NCCIC.

4. MITIGATIONS

WAGO recommends affected users update to the latest firmware (FW 02). Contact
WAGO support for update files and specific instructions.

WAGO also recommends the following mitigations:

  o Update the device to the latest firmware.
  o Restrict network access to the device.
  o Do not directly connect the device to the Internet.
  o Restrict the number of users with access to the device to a minimum.
  o Change the default passwords of devices.
  o Do not install software from untrusted sources.
  o Do not open websites or follow links from untrusted sources.

WAGO has published a security advisory that can be viewed here:

https://www.wago.com/medias/SA-WBM-2018-004.pdf

NCCIC recommends users take defensive measures to minimize the risk of
exploitation of this vulnerability. Specifically, users should:

  o Locate control system networks and remote devices behind firewalls, and
    isolate them from the business network.
  o 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.

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

NCCIC 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
on the ICS-CERT website 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 NCCIC for tracking
and correlation against other incidents.

NCCIC also recommends that users take the following measures to protect
themselves from social engineering attacks: 

  o Refer to Recognizing and Avoiding Email Scams for more information on
    avoiding email scams. 
  o Refer to Avoiding Social Engineering and Phishing Attacks for more
    information on social engineering attacks.


Contact Information

For any questions related to this report, please contact the NCCIC at:

Email: NCCICCUSTOMERSERVICE@hq.dhs.gov
Toll Free: 1-888-282-0870

For industrial control systems cybersecurity information:  http://
ics-cert.us-cert.gov 
or incident reporting:  https://ics-cert.us-cert.gov/Report-Incident?

The NCCIC continuously strives to improve its products and services. You can
help by choosing one of the links below to provide feedback about this product.

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