S2OPC — Safe, Secure, Open Source OPC-UA

Why S2OPC ?¶

As a result of the R&D project INGOPCS initiated with the support of ANSSI, Systerel launched the S2OPC product whose development has been carried out with Systerel’s own funding.

Before the beginning of the project, the ANSSI did the following analysis:

• there are an increasing number of attacks on SCADA (see for example Stuxnet in 2010),

• these SCADA and ICS are more and more interconnected or even connected to external networks such as the Internet,

• there was little or no secure protocol stack for SCADA on the market 1,

• the need for an open source, secure and modern OPC UA stack developed in France or in Europe was becoming more and more important.

Project objectives¶

The project was launched with the following four main objectives:

Certification first and foremost

A security or safety certification cannot be improvised at the end of the project. The design and organizational choices must be made from the outset in a way that takes into account the constraints of certification. For S2OPC three types of certification are being considered:

• interoperability certification within the framework of the OPC foundation: the certificate should be obtained in Q1 2020.

• one or more security certification issued by ANSSI: a first ANSSI certification assessment is in progress.

• a safety certification according to EN-50128 or similar standards: S2OPC is already embedded in a SSIL2 railway equipment.

Embedded development

The need of the industry is clearly to be able to embed a secured stack on small, energy-efficient equipment.

S2OPC is of modest size (1MB ROM, 256KB RAM for the OPC UA server and the PubSub feature) and in addition to Linux and Windows, it has already been ported to FreeRTOS, Zephyr, VxWorks, …

Scalability

The stack is designed to run on systems supervising several plants and they must be able to handle hundreds of thousands of variables and messages without a glitch.

Performance

Performance is a persistent concern of the design team and all design decisions take this factor into account. S2OPC has always ranked first on our performance benchmarks.

Real-time performance are not forgotten as we achieved PubSub transmissions with a periodicity of 100 µs between two STM32 nucleo-144 cards.

Certification¶

The certification requirements dictate two constraints on the development. The first one is to obtain a very good product with respect to the security or safety requirements.

And the second one is to be able to provide evidences of the quality of the product.

The expected evidences are from different types. For example:

• the existence of a development process (ISO9001…),

• the existence of documentation (plans, specification, design, verification reports…)

• the deployment of test benches (unitary, integration, validation, fuzzing, penetration testing…)

• the production of traceability (who, when, what…),

• …

In any case, these constraints must be taken into account at the very beginning of the project: it is extremely difficult to bring an existing product to a certification.

Open Source Benefits¶

*** CID 350732:  Resource leaks  (RESOURCE_LEAK)
/builds/systerel/S2OPC/csrc/services/b2c/address_space_bs.c: 419 in address_space_bs__read_AddressSpace_Value_value()
413         }
414         else
415         {
416             if (SOPC_LocalizedText_Id == value->BuiltInTypeId)
417             {
418                 // Get preferred localized text(s) (single value, array or matrix)
    CID 350732:  Resource leaks  (RESOURCE_LEAK)
    Overwriting "value" in "value = util_variant__set_PreferredLocalizedText_from_LocalizedText_Variant(value, address_space_bs__p_locales)"
    leaks the storage that "value" points to.
419                 value =
420                     util_variant__set_PreferredLocalizedText_from_LocalizedText_Variant(value, address_space_bs__p_locales);
421             }
422         }
423
424         if (address_space_bs__index_range == NULL || address_space_bs__index_range->Length <= 0)

Footnotes¶

1

Kaspersky have performed a security analysis of an OCP-UA stack in which they found 17 zero-day vulnerabilities: https://ics-cert.kaspersky.com/reports/2018/05/10/opc-ua-security-analysis/