Belden's Tofino Security brand has published new research showing that patching is often ineffective in providing protection from the multitude of vulnerability disclosures and malware targeting critical infrastructure systems today
While patching such systems is important as part of an overall Defense in Depth strategy, the difficulties of patching for industrial systems mean that compensating controls such as Tofino Security Profiles are often a better method of providing immediate protection.
Since the discovery of the Stuxnet malware in 2010, industrial infrastructure has become a key target for security researchers, hackers, and government agents.
Designed years ago with a focus on reliability and safety, rather than security, Supervisory Control and Data Acquisition (SCADA) and Industrial Control Systems (ICS) products are often easy to exploit.
As a result, there has been exponential growth in government security alerts for these systems in the past two years. In addition, they have attracted some of the most sophisticated (Stuxnet, Night Dragon, Flame) and damaging (Shamoon) cyberattacks on record.
Eric Byres, CTO and vice president of engineering at Tofino Security, investigated the effectiveness of patching for protecting control systems from vulnerability exploits and malware.
His work revealed that:
- The number of vulnerabilities existing in SCADA/ICS applications is high, with as many as 1,805 yet to be discovered vulnerabilities existing on some control system computers.
- The frequency of patching needed to address future SCADA/ICS vulnerabilities in both controllers and computers likely exceeds the tolerance of most SCADA/ICS operators for system shutdowns. Unlike IT systems, most industrial processes operate 24×7 and demand high uptime. Weekly shutdowns for patching are unacceptable.
- Even when patches can be installed, they can be problematic. There is a 1 in 12 chance that any patch will affect the safety or reliability of a control system, and there is a 60% failure rate in patches fixing the reported vulnerability in control system products. In addition, patches often require staff with special skills to be present. In many cases, such experts are often not certified for access to safety regulated industrial sites.
- Patches are available for less than 50% of publically disclosed vulnerabilities.
- Many critical infrastructure operators are reluctant to patch as it may degrade service and increase downtime.
When patching is not possible, or while waiting for a semi-annual or annual shutdown to install patches, an alternative is to deploy a workaround, also known as a ‘compensating control’.
Compensating controls do not correct the underlying vulnerability; instead, they help block known attack vectors.
Examples of compensating controls include product reconfigurations, applying suggested firewall rules, or installing signatures that recognise and block malware.
Another compensating control is Tofino Security Profiles, available in Belden’s Tofino Security product line. Tofino Security Profiles are rule and protocol definitions that address newly disclosed vulnerabilities.
They provide a simple way for automation system vendors to create and securely distribute malware protection.
Operators benefit from a single, easy-to-deploy package of tailored rules that can be installed without impacting operations. The result is that critical industrial infrastructure facilities can quickly and effectively defend themselves against new threats.
“My research highlights the multiple challenges with patching for SCADA and ICS systems,” remarked Eric Byres.
“To secure facilities, critical infrastructure operators should pursue a Defense in Depth strategy that includes patching when possible, and use compensating controls for protection when patching is not possible.”
Belden is publishing a series of blog articles on its patching research and is accompanying them with useful documents.
These documents include:
- “Patching for Control System Security – A Broken Model?”; a presentation that summarises its patching research,
- “Patching for Control System Security – A Broken Model?“ a peer reviewed published paper,
- and “Solving the SCADA/ICS Security Patch Problem”, a White Paper.
Tofino Security provides practical and effective industrial network security and SCADA security products that are simple to implement and that do not require plant shutdowns. Its products include configurable security appliances with a range of loadable security modules plus fixed function security appliances made for specific automation vendor applications.
Tofino Security products protect zones of equipment on the plant floor, and are complementary to Belden’s Hirschmann brand, which leads industrial networking solutions.
Both groups service and secure industrial networks in the oil and gas, utilities, transportation and automation industries.
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