ENISA issues recommendations on SCADA patching

“How long can we afford having critical infrastructures that use unpatched SCADA systems?” the EU’s cyber security Agency ENISA asks, and advises EU Member States to proactively deploy patch management to enhance the security of SCADA systems.

Much of Europe’s critical infrastructure resides in sectors such as energy, transportation, water supply. These infrastructures are largely managed and controlled by SCADA (Supervisory Control and Data Acquisition) systems (a subgroup of Industrial Control Systems -ICS). In the last decade SCADA technology has gone from being isolated systems into open architectures and standard technologies that are highly interconnected with other corporate networks and the Internet.

A consequence of this transformation is the increased vulnerability to outside attacks. One way to enhance the security of SCADA is through the application of patches.

At the moment, two of the key important issues with patching are the failure rate of patches (60%) and the lack of patches; less than 50% of the 364 public vulnerabilities had patches available for SCADA.

ENISA has identified several best practices and recommendations regarding patching that can improve the security posture of SCADA environments, from which they would like to mention the following:

Compensating Controls

• Increase in depth defence through network segmentation to create trusted zones that communicate using access controls
• Hardening the SCADA systems by removing unnecessary features
• Usage of techniques such as Application White Listing and Deep Packet Inspection
• Patch management program and service contract
• Asset owners should also establish a patch management service contract to define on the responsibilities of both the vendor and the customer in the patch management process
• Asset owners should always conduct their own tests. This can be done virtually or by maintaining separate systems to test on
• Certified systems should be re-certified after a patch is applied.

“Although patch management is not a silver bullet to resolve the security issues of SCADA systems it is nevertheless important that organisations establish a patch management policy,” remarked Professor Udo Helmbrecht, Executive Director of ENISA. “The European Union or the Member States could increase the awareness of patches through enforcing patch management when new requirements for devices are established.”

For more details, download the full report here.