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             AUSCERT External Security Bulletin Redistribution

                               ESB-2018.2793
                  WECON PLC Editor security vulnerability
                             19 September 2018

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

Product:           WECON PLC Editor
Publisher:         ICS-CERT
Operating System:  Windows
Impact/Access:     Execute Arbitrary Code/Commands -- Remote with User Interaction
Resolution:        Mitigation
CVE Names:         CVE-2018-14792  

Original Bulletin: 
   https://ics-cert.us-cert.gov/advisories/ICSA-18-261-01

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Advisory (ICSA-18-261-01)

WECON PLC Editor

Original release date: September 18, 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 6.3
  o ATTENTION: Exploitable remotely/low skill level to exploit
  o Vendor: WECON
  o Equipment: PLC Editor
  o Vulnerability: Stack-based Buffer Overflow

2. RISK EVALUATION

Successful exploitation of this vulnerability could result in unauthorized code
execution within the current process.

3. TECHNICAL DETAILS

3.1 AFFECTED PRODUCTS

The following version of PLC Editor, a ladder logic software, are reported to
be affected:

  o 1.3.3U

Additional versions may also be vulnerable.

3.2 VULNERABILITY OVERVIEW

3.2.1    STACK-BASED BUFFER OVERFLOW CWE-121

When processing project files a stack-based overflow vulnerability can be
exploited, which may allow an attacker to execute code under the current
process.

CVE-2018-14792 has been assigned to this vulnerability. A CVSS v3 base score of
6.3 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:R/S:U/C:L
/I:L/A:L).

3.3 BACKGROUND

  o CRITICAL INFRASTRUCTURE SECTORS: Critical Manufacturing, Energy, Water and
    Wastewater Systems
  o COUNTRIES/AREAS DEPLOYED: Worldwide
  o COMPANY HEADQUARTERS LOCATION: China

3.4 RESEARCHER

Natnael Samson (Natti) working with Trend Micro's Zero Day Initiative reported
this vulnerability to NCCIC.

4. MITIGATIONS

WECON has verified the vulnerability but has not yet released an updated
version.

All users should limit application interaction to only trusted files and update
software to the latest version as updates become available.

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

  o Do not click web links or open unsolicited attachments in email messages.
  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.

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

  o Minimize network exposure for all control system devices and/or systems,
    and ensure that they are not accessible from the Internet.
  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.

No known public exploits specifically target this vulnerability.


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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