IBHsoftec S7-SoftPLC CPX43 Heap-based Buffer Overflow Vulnerability

OVERVIEW

Ariele Caltabiano (kimiya) working with Trend Micro’s Zero Day Initiative has identified a buffer overflow vulnerability in IBHsoftec’s S7-SoftPLC. IBHsoftec has produced a new version to mitigate this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

IBHsoftec reports that the vulnerability affects the following versions of S7-SoftPLC:

• S7-SoftPLC versions prior to 4.12b

IMPACT

An attacker who exploits this vulnerability may be able to affect integrity, confidentiality, and availability of the target device.

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

IBHsoftec GmbH is a Germany-based company that sells products through distributors worldwide.

S7-SoftPLC, is a software program meant to replace a hardware PLC. These products are deployed across several sectors including Critical Manufacturing, Energy, and Water and Wastewater Systems. IBHsoftec estimates that these products are used primarily in Europe, Asia, and the United States.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

Object memory can read a network packet that is larger than the space that is available.

CVE-2016-8364NVD, https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2016-8364, NIST uses this advisory to create the CVE web site report. This web site will be active sometime after publication of this advisory. has been assigned to this vulnerability. A CVSS v3 base score of 9.8 has been calculated; the CVSS vector string is (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).CVSS Calculator, https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, web site last accessed November 01, 2016.

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

IBHsoftec has released a new version to address this vulnerability. It can be located on its web site at the following locations:

https://download.ibhsoftec.com/english/Demos/SoftPLC-Demo.exe

http://download.ibhsoftec.com/neutral/SoftPLC-Setup.exe

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.