Kepware Resource Exhaustion Vulnerability

OVERVIEW

Adam Crain of Automatak and Chris Sistrunk of Mandiant have identified a resource exhaustion vulnerability in the Kepware Technologies’ DNP Master Driver for the KEPServerEX Communications Platform. Kepware Technologies has produced a new version that mitigates this vulnerability.

This vulnerability could be exploited remotely.

AFFECTED PRODUCTS

The following versions are affected:

• Kepware Technologies’ DNP Master Driver for the KEPServerEX Communications Platform Versions 5.16.728.0 and earlier.

IMPACT

An attacker who exploits this response processing vulnerability may be able to crash the OPC Server application software running on the target system.

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

Kepware Technologies is a US-based company that maintains offices primarily in Portland, Maine. The KEPServerEX Communications Platform is used for industry and third-party connectivity communication software for automation, both OPC and embedded device communications.

The affected product is a Microsoft Windows-based software that facilitates connectivity to multiple DNP3 compliant devices such as HMI, RTU, PLC and meters.

According to Kepware Technologies, the KEPServerEX is deployed worldwide in over 100 countries, across several sectors including Chemical, Commercial Facilities, Critical Manufacturing, Energy, Food and Agriculture, Information Technology, and Water and Wastewater Systems.

VULNERABILITY CHARACTERIZATION

VULNERABILITY OVERVIEW

UNCONTROLLED RESOURCE CONSUMPTION (RESOURCE EXHAUSTION)CWE-400: Uncontrolled Resource Consumption (‘Resource Exhaustion’), http://cwe.mitre.org/data/definitions/400.html, web site last accessed February 24, 2015.

A vague interpretation of the DNP3 protocol may allow a specially crafted response to create large numbers of entries in the master in some implementations. This is not a universal problem for all DNP3 users, vendors, or integrators, but it may occur.

CVE-2014-5425NVD, http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2014-5425, web site last accessed February 24, 2015. has been assigned to this vulnerability. A CVSS v2 base score of 7.5 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:P/I:P/A:P).CVSS Calculator, http://nvd.nist.gov/cvss.cfm?version=2&vector=AV:N/AC:L/Au:N/C:P/I:P/A:P, web site last accessed February 24, 2015.

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 moderate skill would be able to exploit this vulnerability.

MITIGATION

Remote devices should not return a variation of 0 to a master, and a master that encounters a zero length message from a remote should stop processing that message.

DNP3 Application Note AN2013-004b Validation of Incoming DNP3 Data, published August 13, 2014, addresses this issue. This bulletin may be downloaded at:

<https://www.dnp.org/DNP3Downloads/AN2013-004b Validation of Incoming DNP3 Data.pdf&gt;)

Kepware Technologies has produced a new version of the software, V5.17.495.0, which resolves the vulnerability. Information about the new version is available at the Kepware support site to registered users at (login required):

<https://my.kepware.com/mykepware/Login.aspx&gt;

Kepware Technical Support can be called at:

207-775-1660 or 1-888-537-9273, Ext 211. Hours of operation are 8am to 5pm US Eastern Time (GMT‑5), Monday to Friday.

Kepware Technical email is: [email protected].

ICS-CERT encourages asset owners to take additional defensive measures to protect against this and other cybersecurity risks.

• 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 VPN is only as secure as the connected devices.

ICS-CERT also provides a section for control systems security recommended practices on the ICS-CERT web page at: http://ics-cert.us-cert.gov/content/recommended-practices. Several recommended practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies. ICS-CERT reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

Additional mitigation guidance and recommended practices are publicly available in the ICS‑CERT Technical Information Paper, ICS-TIP-12-146-01B—Targeted Cyber Intrusion Mitigation Strategies, that is available for download from the ICS-CERT web site (http://ics-cert.us-cert.gov/).

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.