16 December 2016
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2016.3003 Fatek Automation PLC WinProladder Stack-Based Buffer Overflow Vulnerability 16 December 2016 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: Fatek Automation PLC WinProladder Publisher: ICS-CERT Operating System: Network Appliance Impact/Access: Execute Arbitrary Code/Commands -- Remote with User Interaction Resolution: Mitigation CVE Names: CVE-2016-8377 Original Bulletin: https://ics-cert.us-cert.gov/advisories/ICSA-16-350-01 - --------------------------BEGIN INCLUDED TEXT-------------------- Advisory (ICSA-16-350-01) Fatek Automation PLC WinProladder Stack-Based Buffer Overflow Vulnerability Original release date: December 15, 2016 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/. OVERVIEW A researcher working with Trend Micros Zero Day Initiative (ZDI) has identified a stack-based buffer overflow vulnerability in Fatek Automations 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 OVERFLOW[a] 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-2016-8377[b] 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 ICSCERT 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. a. CWE-121: Stack-based Buffer Overflow, http://cwe.mitre.org/data/definitions/121.html, web site last accessed December 15, 2016. b. NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8377, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. c. CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S..., web site last accessed December 15, 2016. - --------------------------END INCLUDED TEXT-------------------- You have received this e-mail bulletin as a result of your organisation's registration with AusCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to email@example.com and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/render.html?cid=1980 =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: firstname.lastname@example.org Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). 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