CROSS-REFERENCE TO RELATED APPLICATION

This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2019-199374 filed on Oct. 31, 2019, the disclosure of which is incorporated by reference herein.

BACKGROUND

Technical Field

The present disclosure relates to a communication device, an abnormality determination device, a method of operating communication device, an abnormality determination method, and storage mediums storing programs for operating communication device and abnormality determination.

Related Art

Japanese Patent Application Laid-Open (JP-A) No. 2014-146868 discloses a technique that, in a case in which first data that has a same identifier as received data that is used as a reference and whose reception interval is shorter than a predetermined period, is received, waits until the predetermined period has elapsed from the time of reception of the received data that is used as the reference, for reception of data that has the same identifier as the first data. In this technique, when second data that has the same identifier as the first data is received during the time of waiting for reception, it is judged that fraud (a spoofing attack or the like) has occurred and processing in cases of period abnormality detection is carried out.

In a technique of determining communication abnormalities such as in the technique of JP-A No. 2014-146868, if sensing rules, which are the standards for judging or determining whether or not there are communication abnormalities, are not set in advance so as to match the communication specifications of the onboard system prescribed for each vehicle, erroneous determination of communication abnormalities will arise. However, if sensing rules are created for each of respective vehicles at which the communication specifications of the onboard systems differ, the costs involved in creating the sensing rules increase.

SUMMARY

The present disclosure has been made in consideration of the above-described circumstances, and is to provide a communication device, an abnormality determination device, methods and storage mediums storing programs that have improved abnormality sensing accuracy, without creating sensing (detection) rules for each of respective vehicles at which the communication specifications of the onboard systems are different.

A first aspect of the present disclosure is a communication device having: a first judging section that performs, on received data, a communication abnormality determination based on detection rules; and a setting section that compares a category of data, which the first judging section has determined to represent a communication abnormality during a current trip, with a category of data that the first judging section has determined to represent a communication abnormality during a previous trip, and set a first category of data that has been determined to represent a communication abnormality during each of n trips, wherein n≥2, or a second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, to be a suppression target for which determination thereof as representing a communication abnormality by the first judging section is to be suppressed.

In the first aspect, a determination as to a communication abnormality is made on received data on the basis of the detection rules. Here, in a case in which the detection rules have a portion that does not match the communication specifications of the onboard system, data of a category corresponding to that portion will repeatedly be determined as being a communication abnormality. To address this, in the disclosure of the first aspect, a category of data, which is repeatedly determined to be a communication abnormality in n trips is set to be an object of suppression (i.e., suppression target) for which determination thereof as a communication abnormality is to be suppressed.

Due thereto, it is learned that the category of data, which corresponds to the portion of the detection rules that does not match the communication specifications of the onboard system, is a suppression target, and the accuracy of sensing abnormalities may be improved without creating detection rules for each of plural vehicles at which the communication specifications of the onboard systems are different. Further, because detection rules of vehicles, at which the communication specifications of the onboard systems differ, may be shared, the costs needed for creating the detection rules may be reduced.

In the first aspect, the setting section may be configured to not set, as the suppression target, a third category of data that has not been determined to represent a communication abnormality during at least one trip among the n trips, or a fourth category of data for which the frequency of having been determined to represent a communication abnormality during the n trips is less than a predetermined value.

In the above-described structure, a category of data, which has a low frequency of being determined to be a communication abnormality in n trips, is not set as a suppression target. Therefore, a communication abnormality, which is due to a spoofing attack or the like, being set as a suppression target may be avoided.

The first aspect may be structured such that, the setting section set a flag to “valid” for the first category of data that has been determined to represent a communication abnormality during each of the n trips, or the second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, the flag being used for suppressing determination of the data as representing a communication abnormality by the processor, and among data for which a communication abnormality has been detected based on the detection rules, the first judging section does not determine data of categories for which the flag has been set to valid to represent a communication abnormality.

In the above-described structure, the setting of a category of data, which is repeatedly determined to be a communication abnormality in n trips, as a suppression target for which determination thereof as a communication abnormality is to be suppressed, may be realized by the simple processing of setting a flag that is for suppressing the determination thereof as a communication abnormality.

The first aspect may be structured such that the data includes a CAN communication frame, and the first judging section detects, based on the detection rules, at least one of an abnormality of an ID, an abnormality of a DLC, or an abnormality of a transmission period of the frame, as the communication abnormality.

In CAN communication, there are often cases in which a communication abnormality that is due to a spoofing attack or the like manifests as any of an abnormality of the ID, an abnormality of the DLC, or an abnormality of the transmission period of the CAN communication frame. In the above-described structure, because at least one of the above-described respective abnormalities is detected as a communication abnormality, communication abnormalities that are due to spoofing attacks and the like may be detected.

In the first aspect, the detection rules may be shared by plural types of vehicles for which communication specifications of onboard systems are not the same.

In the above-described structure, because the detection rules are shared by plural types of vehicles at which communication specifications of onboard systems are not the same, costs such as those required in creating determination rules may be reduced.

A second aspect of the present disclosure is an abnormality determination device having: an acquiring section that acquires categories of data that have been set as suppression targets, from plural vehicles at each of which the communication device of the first aspect is installed and for which communication specifications of onboard systems are the same; and a second judging section that compares the acquired categories of data that have been set as the suppression targets with one another, and determine a vehicle for which there are no vehicles having the same category of data that has been set as the suppression target, or a vehicle for which there are relatively few vehicles having the same category of data that has been set as the suppression target, to be abnormal.

In the second aspect, categories of data that have been set as objects of suppression (i.e., suppression target) are acquired respectively from plural vehicles at which the communication specifications of the onboard systems are the same. Here, at the plural vehicles, the communication specifications of the onboard systems are the same. Therefore, in principle, at a vehicle at which the category of data that is set as a suppression target is the same but that has been subjected to a spoofing attack or the like, the category of the data that is set as a suppression target may be different from other vehicles.

In the second aspect, by using this, the categories of data, which have been set as suppression targets and have been acquired respectively from plural vehicles, are compared with one another. A vehicle, for which there are no vehicles having the same category of data that has been set as a suppression target, or a vehicle, for which there are few vehicles having the same category of data that has been set as a suppression target, is determined to be abnormal. Due thereto, the accuracy of detecting abnormalities that are due to spoofing attacks or the like may be improved, without creating detection rules for each of respective vehicles at which the communication specifications of the onboard systems differ.

In the second aspect, the second judging section may compare the category of data that has been set as the suppression target with the communication specifications, and may further determine that a vehicle, at which the category of the data that has been set as the suppression target does not match the communication specifications, is abnormal.

In a vehicle that has been subjected to a spoofing attack or the like, there are cases in which a category of data that does not match the communication specifications is included among the categories of data that have been set as suppression targets. In the above-described structure, a vehicle at which the category of the data that has been set as a suppression target does not match the communication specifications, is also determined to be abnormal. Therefore, the accuracy of detecting abnormalities that are due to spoofing attacks or the like may be further improved.

A third aspect of the present disclosure is a method of operating an onboard communication device, the method including: performing, on received data, a communication abnormality determination based on detection rules; and comparing a category of data, which has been determined by the determination to represent a communication abnormality during a current trip, with a category of data that has been determined to represent a communication abnormality in a previous trip, and setting a first category of data that has been determined to represent a communication abnormality during each of n trips, wherein n≥2, or a second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, to be a suppression target for which determination thereof as representing a communication abnormality is to be suppressed.

A fourth aspect of the present disclosure is an abnormality determination method, including: acquiring categories of data, which have been set as suppression targets by the method of operating an onboard communication device of the third aspect, from each of plural vehicles for which communication specifications of onboard systems are the same and at which the onboard communication devices are installed; and comparing the acquired categories of data that have been set as the suppression targets with one another, and determining a vehicle for which there are no vehicles having the same category of data that has been set as the suppression target, or a vehicle for which there are relatively few vehicles having the same category of data that has been set as the suppression target, to be abnormal.

A fifth aspect of the present disclosure is a non-transitory storage medium that stores a program executable by a computer to perform communication processing, the communication processing including: performing, on received data, a communication abnormality determination based on detection rules; and comparing a category of data, which has been determined by the determination to represent a communication abnormality during a current trip, with a category of data that has been determined to represent a communication abnormality during a previous trip, and setting a first category of data that has been determined to represent a communication abnormality during each of n trips, wherein n≥2, or a second category of data for which a frequency of having been determined to represent a communication abnormality during the n trips is greater than or equal to a predetermined value, to be a suppression target for which determination thereof as representing a communication abnormality is to be suppressed.

A sixth aspect of the present disclosure is a non-transitory storage medium that stores a program executable by a computer to perform abnormality determination processing, the abnormality determination processing including: acquiring categories of data, which have been set as suppression targets by the communication processing of the fifth aspect, from each of plural vehicles for which communication specifications of onboard systems are the same; and comparing the acquired categories of data that have been set as the suppression targets with one another, and determining a vehicle for which there are no vehicles having the same category of data that has been set as the suppression target, or a vehicle for which there are relatively few vehicles having the same category of data that has been set as the suppression target, to be abnormal.

The present disclosure may improve the accuracy of detecting abnormalities, without creating detection rules for each of respective vehicles at which the communication specifications of the onboard systems are different.

