By Rich Merritt, Senior Technical Editor
Listed below are the verbatim answers from vendors to questions we posed about control system security. These have been only lightly edited for clarity and to correct errors. Be warned that some of these responses are quite commercial and go far beyond what CONTROL magazine would allow to appear in print. We felt that the pure technical information weaved among the product sales pitches is quite valuable, so we let the promotional material stand. Among the responding companies are process control vendors, software companies, security consultants, I/O manufacturers and Microsoft.
What do you advise your customers to do?
Make the integrity (security, availability, etc.) of your systems a business responsibility and a priority. This does not mean that it becomes THE priority. Unless someone is explicitly responsible for this faction (and empowered to act or establish procedure) it will not get done, except perhaps sporadically. This also allows you are able to budget for and track the team responsible.
Stay current. By far, the greatest number of non-trivial intrusions, interruptions and systems disasters happen in environments where components are forgotten, out-of-date, and unpatched. While zero-day worms and viruses may make the news, and are certainly a threat, control systems are even more susceptible to failing in the face of the much more preventable menace. The hopelessly out-of-date immune deficiency condition. Not to make light of a serious matter, immune deficiencies are deadly serious in the world, to man and beast alike. There is a very strong parallel to better immune disorders and unmaintained networked systems.
From a security perspective, a control system is just another host on the network and thus open to all associated network attacks. Depending on the type of control system, the exposure/risk associated with such attacks could certainly have a catastrophic impact. For this reason, Cryptek recommends customers in the control market look at security products that have successfully obtained government level certifications such as Common Criteria and FIPS. In this way, they can have a high level of assurance and trust that their critical control systems and devices will be protected from network level attacks.
Emerson Process Management Power & Water Solutions
We recommend a firewall, a NAT router, and anti-virus software. For our Windows-based systems we provide security configuration guidance. For our TPS systems, weve provided this guidance as part of the TPS system Administration Guide. For the Experion Process Knowledge System (PKS), we provide a Network and Security Planning Guide.In general, we advise our customers to use anti-virus software, high-security configurations of Windows, hotfix installation, specific network topology configurations, and firewalls between the enterprise network and process control network. We also provide network security services. We advise customers to view cybersecurity as an essential part of doing business, not unlike the traditional building security. Industrial plant managers who would never leave their plant door wide open so that anyone could walk in may be doing just that with their networks. The challenge is to implement network security both effectively and economically. Accomplishing that requires as much attention to policy and planning as to technology.One of the biggest reasons process firms are vulnerable, in fact, is that most have NOT established and implemented a formal security policy. As a result, systems are not configured consistently and weaknesses are common. The Carnegie Mellon Institute, in fact, found that 99% of all reported Intrusions resulted from exploitation of known vulnerabilities or of configuration errors for which countermeasures were available.Figuring out which battles to fight is a big part of cybersecurity. No company can afford to fortify themselves against all possible attacks from all possible sources. You have to determine where you are most vulnerable and what is at stake before implementing any technology. We recommend an approach that covers the following areas:-
Assess current security vulnerability from remote and internal threats
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Assess your level of acceptable risk
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Define security policies and procedures
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Implement measures to reduce and/or eliminate risks
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Conduct on-going evaluations and implement processes to account for changes and/or advances in technology
Typically there are two discrete, but related phases to the process: a review phase in which needs, policies and plans are established, and a hardening process in which the corrective means are implemented and monitored.
We also tell customers, however, that success in such a plan requires an almost unprecedented degree of cooperation among management, IT and engineering. One of the most critical management functions will be to determine who actually has responsibility and accountability for cybersecurity. Management must guide definition of goals and objectives, training, internal communications, regulatory compliance, vulnerability and risk assessment and development of policies procedures that must be followed.
Moore Industries-International
What hardware or software helps?
Cryptek's cSecure package is unmatched in security. It's creates capable, flexible, virtual circuits wherever they are needed for any ip-capable control system or component, regardless of the device's operating system, and without affecting anything on the device.
The key is having firewall type access controls deployed at the control system level. Edge-based only security solutions do not properly protect against internal attacks and/or attacks generated from malicious code accidentally brought into the system. Software solutions that run on top of an operating system are only as secure as the OS on which they reside and thus can be susceptible to OS level attacks. Cryptek partners with Quadros Systems Inc. which produces a proprietary real time operating system. The real-time operating system, RTXC, has an integrated security package which provides IT-level security.
For these reasons, Cryptek recommends device level hardware/firm based solutions which are able to provide access control and intrusion prevention at the physical control system level. Hardware/firmware based bump-in-the-wire appliances, such as Cryptek's cSecure product suite, provide the security required.
Regarding software, a spreadsheet may be you most powerful single tool in the fight against intruders and hackers. Track the state of your systems, report on and make maintenance a business priority, and remember to track all the components, especially the quietly forgotten, soon to be upgraded, overhauled or replaced 'legacy' systems. The forgotten is usually the weakest link.
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The addition of third party products such as anti-virus solutions and intrusion detection systems.
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Developing easier ways to manage users and their roles in the control system as far as authenticating users and determining what function they are authorized to perform.
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Hardening workstations (removing unnecessary software).
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Providing security assessments and audits.
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White papers describing best practices on various security topics.
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Inviting utility customers to participate in open discussions via teleconference on the topics of energy security standards and issues.
Emerson Process Management Power & Water Solutions
Best bets include Cisco switches and firewalls, anti-virus software, and terminal servers. (The Honeywell white paper, Securing Process Control Network External Communications provides additional information on this approach.) Installation of Windows XP SP2, which offers advanced security features, is also helpful. While adequate protection of a plant control network level will likely require integration of firewall, intrusion detection and prevention technology with communications devices such as routers, bridges and switches, implementing any technology outside the context of a well developed policy and procedural framework could be both costly and ineffective. Just putting a firewall between the process control network and the rest of the network for example, without configuring it to know what data is essential and what is not, could waste time and money, without adding protection.Even decisions of where to implement firewalls must be policy-driven. Our cybersecurity consultants, for example, typically break out the following security zones: the public Internet, the data center, the plant network, the control network and the field I/O zone, and then deploy a different brand firewalls between each. In addition to working out these configurations, some installations also require protection for sub zones. (See white paper for examples of sub zones)Determining which of these require protection, however, is a matter than must be addressed by a developed and well-documented policy, so that only the necessary technology is deployed. Let's look at software. If you are running Microsoft's most recent operating system, Windows XP SP2 or Windows Server 2003, which contain significant security ehancements, you've already taken a huge step toward reducing your security vulnerability. Keeping your operating systems patched via Windows Update is equally important.But as I said before, up-to-date software is just one aspect of a good security policy. It's important to use a variety of security technologies and to adhere to a well-defined set of policies and procedures. For example, anti-virus software, host-based firewalls, and anti-spyware tools combine to provide multiple layers of protection for a computer. Similar other technologies can be used to provide layers of protection for an enterprise. Norton and McAfee, in my opinion, are the best supported programs.
Moore Industries-International
What have you done to make your products more secure?
Cryptek designs products from conception to meet the highest levels trust and security at the node (i.e. control system) level. Our products are all hardware appliance/firmware based and thus are not susceptible to OS level attacks. Cryptek also brings all of its products through extensive government level security testing through both the NSA Common Criteria security certification process and NIST FIPS process. In fact, Cryptek is the only product to have received Common Criteria Evaluated Assurance Level 4 (EAL-4) in multiple functional areas including Firewall, VPN and Network Management.
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Routing of connections between inside and outside networks through a security server.
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Mesh networking capability, which provides high availability and redundant operations for areas which require real-time communication between process control and other protected zones.
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Dynamic Intrusion Response (DIR) functionality, provided by the Enterasys Ethernet switches used in our control networks. DIR detects abnormal behavior on the enterprise network, and then intervenes to quarantine the offending user or deviant device.
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Industrial-strength virus protection, implemented in partnership with industry leader McAfee
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Collaboration with Microsoft on hardened Window's based software for industrial environments.
And to help customers implement the most cost-effective security solutions, we also offer a fully developed cybersecurity consulting services organization that helps assess, plan, configure and deploy cybersecurity. Our new Site Security Review Service and our System Security Hardening Service, for example, help users develop an effective security plan, identify specific site vulnerabilities, and protect against potentially catastrophic intrusions.
Also, having a clearly defined process for validation, escalation and response to alarms is becoming more and more critical. It does one little good to have alarms going off all over the place if no one knows what to do with them. This is another example of why cybersecurity is as much about management as about technology. We now offer new alarm management services that minimize nuisance alarms and help process control system operators respond more effectively to abnormal situations. These services help analyze, improve and maintain optimal alarm system performance for any brand of distributed control systems (DCS).
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Design: Products are designed with security in mind.
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Default: When customers deploy products out of the box, they are in their most secure configuration, by default.
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Deployment: Once the product is deployed by customers, Microsoft will constantly follow-up with support and patches.
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Communication: Microsoft will communicate regularly to its customers and educate them on how best to use their products to ensure maximum security is deployed.
Microsoft has been at the forefront of designing the most secure products, continuing to improve and support them as security threats change and evolve.
Our Ethernet products were designed to be open and flexible so they can be easily implemented with new and existing legacy control systems. The embedded web server we offer with our product has an optional security feature that once enabled doesn't allow access to any of the channel configurations or viewing or process data.
Moore Industries-International
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Rockwell Software Maintenance Automation Control Center (RMACC) provides security by controlling which users can access an application and what actions they can perform and protects sensitive data by limiting who can retrieve data form a centrally managed archive.
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Rockwell Software RSBizWare PlantMetrics, RSBizWare Historian and RSProduction Portal (a member of the RSBizWare suite) require users to authenticate themselves with a password before they are allowed to access an plication. Users are then granted access to specific functions and data based on their user or group configurations.
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Rockwell Software RSLogix family of ladder logic programming software is designed to operate on Microsoft Windows operating systems and features inherent capabilities that can be configured for more security. For example, RSLogix source protection gives users the ability to protect control routines, while a lockdown tool can provide control lockdown capabilities.
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Rockwell Software RSView Machine Edition(ME), RSView Supervisory Edition(SE) and RSView32 feature a security code-based system that determines each users level of access. Security codes are assigned to graphic displays so that only those with the specified code can open each display. For RSView SE, security codes also can be assigned to applications, preventing unauthorized users from changing applications from RSView Studio or the RSView Administration Console.
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Allen-Bradley VersaView industrial computer familys new security enhancements equip computers with Microsoft Windows XP Service Pack 2 (SP2), with enhanced security features to make managing security easier and more efficient.
Can those improvements be retrofitted to older products?
Yes, Cryptek's device-independent distributed technology works with almost any networked system.
Emerson Process Management Power & Water Solutions
What security problems have you actually seen in the field?
While security has always been a priority, organizations of all types utilities included are continuing to dial up security measures. We are not aware of any security situations at any of our utility customers. When discussing cyber-security for utilities, its important to keep in mind that utility control systems are secured as subnets within a utility's network infrastructure, which is then secured from the Internet. As a result, other parts of the utility's infrastructure must be compromised before the control system is vulnerable.
Emerson Process Management Power & Water Solutions
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Internet worms such as CodeRed Nimda, SQL Slammer have attacked web servers
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Outsiders have tapped into wireless communications paths
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An intruder connects via modem
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Maintenance workers accidentally insert a virus via an infected floppy or CD
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Unauthorized personnel gained access to unprotected PC in an unlocked lab
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A remote users inadvertently introduced a virus into the network
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An intruder enters through the Remote Access Services (RAS) link
Moore Industries-International
Many customers are hesitant to share these types of details outside of their company due to confidentiality.
One large user has told us that his company invested multiple man-years updating all of its automation systems to a later Windows NT Service Pack in response to the Slammer Virus in 2002. This was an unplanned expense, since their systems are designed to run continuously 24/7, 365 days a year, until decommissioning.
Other users have talked about the operating system paradox that showed itself when the Sasser Virus was launched in 2004. This virus attacked only the newer Microsoft operating systems, such as Windows 2000 and Windows XP, but left Windows NT alone. This means that users of older, seemingly less secure, operating systems were actually less vulnerable to threats since hackers do not typically target older operating systems.
What did you do to solve the problesm?
Spot cybersecurity solutions are not effective. We addressed problems through a broader program which usually involves either a comprehensive site review a hardening intervention or both.
Tips and Techniques
A DCS should not be connected directly or indirectly to the internet. This can only be enforced if the end user institutes a "Do not connect" policy and periodically verifies that rogue modems or high speed internet and non-DCS LAN connections do not exist.
Additionally, DCS control devices must not be connected directly or indirectly to an office network without suitable protection, such as a properly maintained firewall and anti-virus protection. All anti-virus software should be certified by the DCS manufacture. The last thing a user wants to do is install anti-virus software only to discover that vital DCS functionality has been lost. Loss of DCS functionality could be just as costly as the virus attack. Users should disable unneeded operating system services (example: File and Printer Sharing) that make âexternal connections more vulnerable. Do not permit computers to boot from floppy or CD-ROM; only the hard drive. This is a simple change to the computer's BIOS setup.
Vendors default passwords within a DCS should be changed immediately upon commissioning. This must be driven home to all the users. To do otherwise is like leaving your spare house key under your doormat. Any determined cyber criminal can locate the vendor's standard product manuals through the internet that contain the default passwords for easy access to an otherwise unsecured system. Do not leave the system vulnerable. Extend your cyber security blanket beyond the DCS. Consider all the devices that are connected to the DCS through the assortment of data-links created to reduce islands of automation. That PLC on the DI water-processing skid that shares information with the DCS may have an unsecured connection to the plant LAN. Chances are it is configured with the factory default passwords. Some innocent looking subsystem may contain an unsecured PLC that could become the entry point into your DCS system.
Be wary of third-party application software packages that are linked to the DCS through and OPC client server relationship. That whiz-bang optimization package that reports production results to accounting may have read, write, and edit capability of specific areas within the DCS; a virtual hacker's playground. Whenever Metso Automation ships a system or add-on workstation we verify that all supplied HMI equipment is free of viruses. Additionally, Metso Automation keeps all supplied equipment up-to-date with operating system security patches that are available from our Life-Cycle Services Team. Customers with long-term support contracts are notified immediately of cyber threats, security patches, and suggested protective measures.
We recognized the potential for cyber threats early on and designed various safeguards into the present maxDNA product. We do not however discuss specific customer security issues with any third party.
Implement plant floor network security processes, policies and procedures. Technology is only 20% of the solution, the other 80% involves people understanding and supporting corporate security polices and procedures. Implement strict plant floor user Authentication and Authorization for secure access to automation devices Implement a business continuity and recovery program so that you can recover as soon as possible from a serious incident.
Implement strict controls on plant floor workstations. Minimize both the loading of unnecessary office tools and the ability to move portable PCs inside and outside the plant floor environment Support automatic program backup, verification and recovery, audit trail, event logs, etc.
Based on our discussions with control system users, here is what Siemens has found customer expectations / requirements to be. Users should make sure their automation vendor is taking steps to support these requirements.
Plant control systems:
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Must be able to operate in a connected environment (tying together automation networks and corporate networks).
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Require the ability to harvest data from the operational environment in near-real-time mode.
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Must at least be tolerant of mainstream information protection, security and management tools. This would include anti-virus, vulnerability assessment, and asset management tools as examples.
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Must be current in regards to threats, vulnerabilities and the required responses to thwart them.
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Should support the ability to have security agents/tools installed and active during online operation.
Vendors should:
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Provide recommendations or guidelines on how to use security and information protection tools (such as anti-virus scanners) in conjunction with their automation platform.
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Have a well-defined policy for immediate testing of new Microsoft Security patches and Virus scanner profiles and for notification of testing results.
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Have a well-defined policy regarding whether new Microsoft Security patches can be installed as soon as they are available, or whether users must wait for compatibility test results by the host vendor.
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Operating system patch support must be current (within 6 months of release).
Siemens, like many other vendors, has stations in their system test labs for PCS 7 that are dedicated to testing the latest security patches from Microsoft. They also test the newest signatures for virus scanning software, including McAfee, Norton, and Trend Micro. Testing of new patches begins on the same day that they are released. Siemens notifies customers of the results of the patch testing as soon as completed.
It is also permissible for a customer to install new security patches from Microsoft immediately upon release (if necessary), without prior approval from Siemens. However, it is recommended that customers wait for the formal results of testing by Siemens, and associated approval, prior to installing the security patches. As stated above, Siemens testing of security patches begins on the same day that they are released by Microsoft.
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