WO2019029868A1

WO2019029868A1 - Method for testing the integrity of components of a system, and arrangement for carrying out the method

Info

Publication number: WO2019029868A1
Application number: PCT/EP2018/065288
Authority: WO
Inventors: Rainer Falk
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-08-11
Filing date: 2018-06-11
Publication date: 2019-02-14
Also published as: DE102017214057A1

Abstract

The invention relates to a method for testing the integrity of system components of a system and to an arrangement for carrying out the method. In accordance with the method a load-dependent temperature fingerprint of the system component of the system for which the integrity is to be tested is detected (2) and is checked (3) and evaluated (4) so as to determine (5) the level (6) of conformity between the load-dependent temperature fingerprint and cross-checked reference information. This is repeated until the determined level (6) of conformity is a result that lies within a predefined tolerance range for the level (6) of conformity. If the result of the determined level (6) of conformity lies outside the predefined tolerance range, reactive measures (8) for eliminating the unsafe system state are performed. The arrangement for carrying out the method comprises appropriate technical means.

Description

description

METHOD FOR CHECKING THE INTEGRITY OF COMPONENTS OF A SYSTEM AND ARRANGEMENT FOR PERFORMING THE PROCESS

The present invention relates to a method for checking the integrity of system components of a system according to the preamble of claim 1. The present invention further meets be ^¬ for performing the method an arrangement according to preamble of claim. 4

In automation systems, for example, a correct function is of the utmost importance. This applies in particular to safety-critical control systems such as, for example, control systems for railway automation, energy network automation, factory automation or process automation.

The system components used for such as control systems are often implemented with the use of technologies that come from the field of education Informa ^¬ tion technology or the electronic technology for general consumers. Therefore, there is a risk that a system component used for, for example control systems for the Step Example automation, for example, for a control unit, an embedded electronic system or unit, for the power of the things (Internet of Things (IoT), so-called all networks) has a malfunction be ^¬ intentionally manipulated.

There is therefore a need for protective measures to a faulty function or make it more difficult, for example, those for Automatisierungssys ^¬ systems manipulation of respective system components.

Different technologies are already known to protect the integrity of such system components: - Secure Boot: Only correctly signed ^software / firmware will be loaded. For this, a hash value or digi ^¬ tale signature charged software / firmware is checked;

- Trusted Boot: Depending on software loaded and their Measurements, that is the hash values of software downloaded ^¬ module that provides access to a cryptographic key is released;

- Verified Boot: It can be a tamper-resistant Bestä ^¬ account the provided loaded software / firmware; - runtime monitoring: checking the integrity of files of a file system, checking the running processes;

- Tamper Seal: A control system unit such case ^¬ play a housing has a seal or a seal. Because ^¬ by a physical manipulation can be detected; - Active Tamperschutz: sensors detect a physical manipulation, for example, a housing switch, a drilling ^¬ protective film, a light sensor or radiation sensor. In a tamper event stored key data is ge ^¬ extinguished.

Furthermore, a so-called "Power Fingerprinting" for the detection of manipulated system components is known in which the power consumption of a system component is analyzed and compared with a reference power consumption profile to detect a malfunction or manipulation by, for example, malware and appropriate reactive measures such as shutdown Such solutions are commercially available but very expensive, so they can only be used in environments with extremely high security requirements, for example in the field of public authorities, for example a disclosure of such "power fingerprinting" can be found on the Internet the internet address:

http://www.powerfingerprinting.com/technololgy.html, and in the published patent application: WO 2012/061663 A2.

Furthermore, so-called safety monitor circuits are known which, for example, have main processors and the software executions. monitor on the main processors. In particular, they can perform tests against fixed test patterns and compare the results of two independent executions. A disclosure of such a monitoring monitor can be found, for example, on the Internet at the Internet address:

https: // www. infineon. com / dgdl / Safety Computing Platform XC2300-CIC61508 Product

Letter .pdf? F0ldld = db3a304317a748360117f45a9c863e84 & fileld = db 3a3043353fdcl6013543303497315d.

Essential functional components of such safety monitors are:

- Internal Test Scheduler / Sequencer: These component genes ^¬ riert sequences of test calls with specified data and checks the result against solid from the test pattern;

- Supply Voltage Monitor: This component detects under- and over-voltage in the power supply of used processors and initiates a reset if necessary;

- Data Verification Unit: This component compares two data variable for equality that are generated within a festgeleg ^¬ th period;

- Task Monitor: Monitor system with defined work patterns for controlling occurring critical workflows with predefined execution budget;

- System Shutdown: System Shutdown. For example, three levels of time-out system shutdown enable flexible shutdown sequences.

Furthermore, coating materials, so-called

Coatings, known for electronic circuits.

The object of the present invention, starting from a method of the aforementioned type, is to provide a method which makes it possible to check the integrity of system components of a system, such as, for example, a control system for, for example, automation. Object of the present invention is further, starting from an arrangement of the type mentioned above to provide an arrangement with which said method is feasible.

With regard to the method, this object is achieved according to the invention with a method having the method steps indicated in the characterizing part of claim 1. With regard to the arrangement, this object is achieved by an arrangement having the features specified in the characterizing part of claim 4.

The inventive method then includes the procedure ^¬ steps of:

- Detecting a load-dependent temperature fingerprint in the health system component to be tested for integrity

- checking and evaluating the detected load-dependent temperature fingerprint against reference information, determining a degree of correspondence between load-dependent temperature fingerprint and counter-verified reference information,

- repeating the detection of the load-dependent temperature fingerprints and Abprüfens and evaluating the detected load-dependent temperature fingerprints against the reference Informa tion under determining a degree of correlation between load-dependent temperature-fingerprint and gegengeprüf ^¬ th reference information as long as the level determined is of agreement a result, that is within a ^pre-¬ given tolerance range of the degree of match, and

- Performing reactive actions if the determined degree of agreement is a result that is outside the specified tolerance range for the degree of agreement.

The method according to the invention enables the secure checking of the integrity of system components, for example of a control system for, for example, automations. Advantageous embodiments of the method according to the invention are the subject of subclaims.

Thereafter, the method according to the invention has, for example, the method step:

Outputting control signals influencing the system to system components of the system as a reactive measure, that the integrity-tested system component of the system at least ultimately generates a load-dependent temperature fingerprint whose degree of agreement with the reference information is a result that is within the specified one Tolerance range for the degree of agreement.

This step allows the underlying system to first try to get back into regular functional operation before taking further action.

In another advantageous embodiment of the method according to the invention, the method step is carried out:

- Issuing an alarm signal as a reactive measure, if the determined degree of agreement between load-dependent

Temperature fingerprint and cross-checked Referenzinformatio ^¬ NEN at the latest after a predetermined period of time is a result that is outside the specified tolerance range for the degree of agreement.

This step allows reaction insbesonde ^¬ re when the integrity of a tested system component no longer exists and the system is at least a specified ^differently bene time even able to return to a safe operating function.

The arrangement has the following technical ^¬ rule means: a monitoring monitor for detecting a load-dependent temperature fingerprint in the integrity-checking system component of the system, and

- Technical means for checking and evaluating the detected load-dependent temperature fingerprint against Referenzinforma ^¬ tions while determining a degree of agreement between load-dependent temperature fingerprint and gegengeprüf ^¬ th reference information. The arrangement according to the invention for carrying out the method according to the invention also makes it possible to reliably check the integrity of system components, for example one

Control system for, for example, automation. Advantageous embodiments of the arrangement according to the invention are the subject of dependent claims.

Thereafter, for detecting the load-dependent temperature fingerprints technical means comprise in the integrity system under test component, at least one tempera ture ^¬ sensor.

In another advantageous embodiment of the inventive arrangement technical means for outputting the system are provided in a manner affecting control signals to system components of the system for carrying out reactive measures to ensure that the inspected for integrity Systemkom ^¬ component of the system at least ultimately produces a load-dependent temperature-fingerprint, whose degree of correspondence against the reference information is a result that is within a predetermined tolerance range for the degree of such match.

In a further advantageous embodiment of the arrangement according to the invention, technical means for outputting at least one single alarm signal are provided for carrying out reactive measures in cases in which the determined degree of agreement between load-dependent elements At the latest after a predetermined period of time has passed, the fingerprint and counter-verified reference information is a result which lies outside the specified tolerance range for the degree of agreement.

With the aid of the measures according to the invention, different types of manipulations or errors in tested system components can be detected. For example, it can be recognized:

- An open housing of a semiconductor device by, for example, an etching of the housing;

an opened automation device with thereafter no longer effective heat sink, since this is then no longer thermally connected in the same way with the processor unit;

- Removed potting compounds or Wärmeleitpads;

- soldered chips that are no longer mounted on the provided Lei ^¬ terplatte;

- changed software / firmware / configurations that led to other load-dependent temperature fingerprints.

The measures according to the invention are advantageously with usual commercial components, for example with compo ^¬ nents that under the terms: on FPGA, system chips, CPUs, microcontrollers and so on are known simply realized. Furthermore, even existing temperature sensors and processing options can be used. The invention can be retrofitted by a firmware / software upgrade to legacy systems.

The present invention is particularly applicable to a Prozes ^¬ soreinheit such as a CPU, a microcontroller, an FPGA, a system on chip, an ASIC, and so forth. There are physical manipulations recognizable such as opening the housing of a processor unit, for example as a semiconductor device, an electronic assembly, for example, as a molded assembly or with a Coating protected assembly, a corresponding board or thermally coupled heat sink.

The invention is based on the fact that processor units used today have temperature sensors. These are used, for example, for adaptive cooling, for example

Fan controller used to make a short-term, temporary overclocking without overheating possible or for diagnosis to monitor the temperature of the environment or on the chip. The temperature depends on the computing load.

According to the invention, the temperature profile of, for example, a processor unit is detected and compared with reference information. In a variation, an error signal may be immediately or after a predetermined time, for example bereitge ^¬ represents. It may, for example, an alarm message ge ^¬ log or provided or it can be deleted specific cryptographic key, or the device can underlying completely or partially, that is in Teilfunktio ^¬ NEN, are blocked.

These can be introduced ^¬ the to check the expected temperature profile of a system component to be tested, targeted a known computational load. In particular, the steep ^¬ ness of the temperature rise and fall can be evaluated ^¬ to. In a variant, the computing load can be modulated with a spreading code method. This makes it possible to separate the effect of the test load from other influences. In a further variant, the spreading code used can be generated cryptographically. However, it is also possible to evaluate an already occurring computing load. It can be carried out a periodical shear ^¬ self-test. The one or more temperature sensors can be present explicitly and can be read out, for example, via a register. In a programmable digital component, a so-called FPGA, or an ASIC, the joy of a digital tal realized oscillator are evaluated in order to conclude on the temperature or the temperature profile ^¬ Shen. In a further variant, the temperature of the processor unit is measured by a field of connected, for example, on the housing glued temperature sensors or optically by means of a thermal imaging camera. It is possible to realize the invention by a Wärmeleitpad containing the corresponding sensors and Auswertelogik. This can be glued to the processor unit.

The analysis of the temperature profile can be carried out in the Prozessorein ^¬ standardized itself, in a separate system component ei ^¬ nes automation device such as in a ^so-¬ called Security controller or in a back-end system, for example in the so-called cloud.

The invention will be explained in more detail with reference to a drawing. Therein: Figure 1 shows a first embodiment of the invention ^shown SEN method

2 shows a second embodiment of the invention ^shown SEN method, and

Figure 3 shows an embodiment of an inventive arrangement in a schematic representation.

In the figure, 1 is a first schematic flow of the inventive method is in the form of a flow chart to se ^¬ hen. After a start 1 of the method, the detection 2 of a load-dependent temperature fingerprint takes place in the case of the system component of the system to be tested for in ^¬ tity. Subsequently ^¬ ßend a system checked 3 and 4 evaluating the detected load-dependent temperature fingerprints against the reference Informa ^¬ functions under determining a degree of 5 is carried out 6 to correspondence between a load-dependent temperature-fingerprint and gegenge ^¬ examined reference information. In a subsequent query step 7, the determined degree 6 is checked for correspondence between load-dependent temperature fingerprint and counter-verified reference information. As long as the level of 6 detected is a result of agreement which is within a predetermined Toleranzbe ^¬ realm of the level 6 of agreement detecting 2 of the load-dependent temperature fingerprints is that Ab ^¬ test 3 and Evaluation 4 of the detected load-dependent temperature fingerprints is repeated against reference information under degree 5 determinations of correspondence between load-dependent temperature fingerprint and counter-verified reference information.

If, in the interrogation step 7, the determined degree of agreement 6 is a result which lies outside of a predefined tolerance range for the degree 6, reactive measures 8 are carried out. Subsequently, the procedure comes to an end 9. As FIG 2 shows in greater detail, may include in a manner affecting control signals to system components of the system to the reactive measures 8 for example, the output 10 of the system that the checked for integrity Systemkompo ^¬ component of the system at least ultimately produces a load-dependent temperature fingerprint whose degree is a result of Convention Stim ^¬ mung against the reference information, which is within the predetermined tolerance range for the degree of agreement. Here, eight subsequent query step can be controlled 11 in a reactive measures whether the reactive level ^¬ took led 8 a success.

If the reactive measures 8 have led to a success, that is, the prescribed tolerances are again met, the method returns, for example, to a point at which the method according to the invention again proceeds as planned. is performed, if necessary again tolerance deviations occur.

If the reactive measures 8 have not led to any success, it may optionally be checked in a query step 12 whether a predetermined time lapse has elapsed for the achievement of a success by, for example, the above reactive measures 8. If no such time lapse has yet occurred, it can be further attempted with the above-mentioned reactive measures 8, for example, to bring the underlying system into a safe state. If such a timing has occurred, for example, an output 13 of an alarm signal as a reactive measure 8 suc ^¬ conditions.

Other reactive measures 8 and constellations of reactive measures 8 are possible and conceivable.

For example, a single alarm signal can be used instead of trying to get through appropriate reactive measures 8 the underlying system selbststän ^¬ dig again in a safe state, equal GR nigstens be output. By

Output of multiple alarm signals, for example, a stage ^¬ scenario of urgency can be realized.

The arrangement 14 according to the invention shown in Figure 3 has technical means 15, which are in the realized by a monitoring ^¬ monitor 16 for detecting 2 of a load-dependent temperature fingerprints integrity to be tested Systemkompo ^¬ component of an underlying system. ^Further , this arrangement has technical means 17 for checking 3 and evaluating 4 the recorded load-dependent temperature

Fingerprints against reference information by finding 5 degrees of agreement between load-dependent Temperature fingerprint and counter-verified Referenzinformatio ^¬ NEN on.

The technical means 15 for detecting 2 of the load-dependent temperature fingerprints in the integrity system under test component further includes at least one temperature sensor Tem ^¬ 18th

Not shown in detail in Figure 3, but optionally present in the inventive arrangement 14, are for

Implementation of Reactive Measures 8 technical means for outputting 10 (not shown in detail in Figure 3) provided by the system in a manner influencing control signals to system components of the system that the integrity tested system component of the system at least ultimately generates a load-dependent temperature fingerprint whose degree of agreement 6 against the reference information is a result that is within a predetermined Toleranzbe ^¬ realm of the level 6 of such a match.

Also not shown in detail in Figure 3, but gege ^¬ appropriate, in the inventive arrangement 14 is provided for carrying out reactive measures 8 technical means for outputting 10 are (in the Figure 3 not shown in detail) reclosure nigstens a single alarm signal 19 in cases provided in which the degree of agreement between 6 determined load-dependent temperature-fingerprint and tested against Re ^¬ conference information is the latest after the expiry of a predetermined period of time, a result which is outside of the predetermined tolerance range for the degree of agreement.

Claims

claims

1. A method for checking the integrity of system components of a system with a method step, wherein a fingerprint is detected for checking the integrity of a system component in the system component to be tested, which is checked against Re ^¬ reference information and evaluated with He ^¬ averaging a degree of agreement between fingerprint and counter-verified reference information, and a procedural step in which criteria are reactive

Measures are carried out, characterized by the Ver ^¬ method steps:

- detecting (2) a load-dependent temperature fingerprint in the integrity of the system component of the system to be tested;

- checking (3) and evaluating (4) the detected load-dependent temperature fingerprint against reference information while determining (5) a degree (6) of correspondence between load-dependent temperature fingerprint and counter-verified reference information,

- Repeating the detection (2) of the load-dependent temperature fingerprint and the checking (3) and evaluation (4) of the detected load-dependent temperature fingerprint against Refe ^¬ renzinformationen while determining (5) a degree (6) to match between load-dependent temperature fingerprint and counter-verified reference information as long as the determined degree (6) of coincidence is a result that is within a predetermined tolerance range for the degree (6), and

- Performing reactive measures (8) when the determined degree (6) of agreement is a result that is outside the predetermined tolerance range for the degree (6) of over ^¬ consensus.

2. The method according to claim 1, characterized by the method step:

Outputting (10) control signals affecting the system in a manner reactive with system components of the system Measure (8) that the tested for integrity Systemkompo ^¬ component of the system ultimately produces a load-dependent temperature-fingerprint at least whose degree (6) is a result to Convention ^¬ humor against the reference information, the within the predetermined tolerance range of the degree (6 ) is in agreement.

3. The method according to claim 1 or 2, characterized by the method step:

- Outputting (10) of an alarm signal (19) as a reactive measure (8) when the determined degree (6) of correspondence between load-dependent temperature fingerprint and counter-verified Re ^¬ reference information at the latest after a predetermined period of time is a result that is outside the predetermined Tolerance range for the degree (6) matches.

4. Arrangement for carrying out the method according to one of claims 1 to 3, comprising technical means for detecting a fingerprint in a systems component of a system to be checked for integrity, for checking and evaluating the fingerprint against reference information and determining a degree of agreement between the fingerprint and gegenge ^¬ examined reference information, and having technical means for carrying out reactive measures, characterized in that

- The technical means (15) for detecting (2) of the fingerprint by a monitoring monitor (16) for detecting (2) a load-dependent temperature fingerprints are realized in the system component to be tested on In ^¬ tegrity of the system, and

the technical means for checking (3) and evaluating (4) a fingerprint by technical means (17) for checking (2) and evaluating (4) the detected load-dependent temperature fingerprint against reference information while determining (5) a degree (6) to match between load-dependent temperature fingerprint and counter-verified reference information.

5. Arrangement according to claim 4, characterized in that

- The technical means (15) for detecting (2) of the load-dependent temperature fingerprint in the case of integrity to be examined ^¬ system component at least a single temperature sensor (18).

6. Arrangement according to claim 4 or 5, characterized in that

- as technical means for performing reactive measures (8) are technical means for outputting (10) of the system in egg ^¬ ner direct influence on control signals to system components of the system provided that the inspected for integrity system component of the system, at least ultimately a load ^¬ dependent temperature Fingerprint whose degree (6) of agreement against the reference information is a result that is within a predetermined tolerance range for the degree (6) of such match.

7. Arrangement according to one of claims 4 to 6, character- ized in that

- As technical means for implementing reactive measures technical means for outputting (10) at least a single alarm signal (19) are provided in cases where the determined degree (6) of agreement between load-dependent temperature fingerprint and counter-verified Referenzinformatio ^¬ NEN at the latest after expiration a predetermined period of time is a result that is out of the predetermined tolerance range for the degree (6) to match.