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Advisory (ICSA-16-350-01)

Fatek Automation PLC WinProladder Stack-Based Buffer Overflow Vulnerability

Original release date: December 15, 2016

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OVERVIEW

A researcher working with Trend Micro’s Zero Day Initiative (ZDI) has identified a stack-based buffer overflow vulnerability in Fatek Automation’s PLC WinProladder application. Fatek Automation (Fatek) has not produced an update to mitigate this vulnerability. ZDI has coordinated with NCCIC/ICS-CERT. ZDI will publish the PLC WinProladder vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following PLC WinProladder version is affected:

  • PLC WinProladder Version 3.11 Build 14701

IMPACT

Successful exploitation of the reported vulnerability may allow an attacker to perform a number of malicious actions including arbitrary code execution.

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

BACKGROUND

Fatek is a Taiwan-based company that maintains distribution offices in several countries around the world.

The affected product, PLC WinProladder, is a PLC programming software. According to Fatek, this product is deployed across several sectors including Commercial Facilities and Critical Manufacturing. Fatek estimates that this product is used primarily in Europe and Asia.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

STACK-BASED BUFFER OVERFLOWa

A stack-based buffer overflow vulnerability exists when the software application connects to a malicious server, resulting in a stack buffer overflow. This causes an exploitable Structured Exception Handler (SEH) overwrite condition that may allow remote code execution.

CVE-2016-8377b has been assigned to this vulnerability. A CVSS v3 base score of 8.0 has been assigned; the CVSS vector string is (AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H).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

Fatek has not responded to requests to work with ICS-CERT to mitigate this vulnerability.

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.
  • 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.

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. 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.

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 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?

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