Communication system

Abstract

To suppress exposure of an internal network under threat due to a packet which is transmitted / received on the internal network.SOLUTION: A communication system comprises a security monitoring device and a first communication device. When a packet is received from another communication device on an internal network, the first communication device holds the received packet as an inspection target and transfers a copy of the inspection target to the security monitoring device. The security monitoring device notifies the first communication device of an inspection result of whether or not the received inspection target is an attack packet to take security countermeasures. When it is received that the inspection target is an attack packet, the first communication device discards the inspection target and when it is received that the inspection target is not an attack packet, the first communication device performs processing of the inspection target.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to communication systems. [Background technology]

[0002] A conventional communication system includes a security monitoring device. The security monitoring device is connected to each communication device on an internal network (i.e., an intranet). The internal network is connected to an external network such as the Internet via the security monitoring device. Such a communication system is disclosed in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-85622 Summary of the Invention [Problem to be solved by the invention]

[0004] A conventional security monitoring device monitors external communications to an internal network, and detects and defends against attacks on the internal network.

[0005] However, conventional security monitoring devices do not detect threats in packets transmitted and received on an internal network. Therefore, even if a packet transmitted from a virus-infected communication device to another communication device on an internal network is an attack packet, the security monitoring device cannot detect that the packet is an attack packet. As a result, the internal network is exposed to threats.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a communication system that can prevent an internal network from being exposed to threats due to packets transmitted and received on the internal network. [Means for solving the problem]

[0007] In order to achieve the above object, a communication system according to one aspect of the present invention includes a security monitoring device that monitors communication between an internal network and an outside, and a first communication device disposed on the internal network. When a packet is received from another communication device on the internal network, the first communication device holds the received packet as an inspection target and transfers a copy of the inspection target to the security monitoring device. The security monitoring device notifies the first communication device of an inspection result as to whether or not the received inspection target is an attack packet for which security measures should be taken. When the first communication device receives a notification from the security monitoring device that the inspection target is an attack packet, it discards the inspection target without processing the inspection target. When the first communication device receives a notification from the security monitoring device that the inspection target is not an attack packet, it processes the inspection target. Effect of the Invention

[0008] The configuration of the present invention can prevent the internal network from being exposed to threats due to packets transmitted and received on the internal network. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a communication system according to one embodiment. [Diagram 2] FIG. 1 is a block diagram of an image processing apparatus according to an embodiment. [Diagram 3] 5 is a flowchart showing a flow of processing performed by a first image processing device according to an embodiment. [Figure 4] FIG. 2 is a diagram illustrating a process performed by a first image processing device according to an embodiment. [Diagram 5]FIG. 2 is a diagram illustrating processes performed by a first image processing device and a second image processing device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] <Communication system configuration> 1, a communication system 100 of the present embodiment includes a plurality of communication devices 10 arranged on an internal network NT. The plurality of communication devices 10 are connected to each other so as to be able to communicate with each other via the internal network NT. In other words, the internal network NT is an intranet.

[0011] The communication system 100 includes a security monitoring device 1. An internal network NT is connected to the outside (in other words, an external network such as the Internet) via the security monitoring device 1. The security monitoring device 1 monitors communications between the internal network NT and the outside. The security monitoring device 1 monitors packets from the outside to the internal network NT and packets from the internal network NT to the outside.

[0012] The security monitoring device 1 is, for example, a UTM (Unified Threat Management) device. As a security countermeasure process, the security monitoring device 1 performs a process of blocking unauthorized access and network attacks from the outside to the internal network NT.

[0013] The communication system 100 includes an image processing device 2 as a communication device 10. The number of image processing devices 2 arranged on the internal network NT is not particularly limited. In FIG. 1, for convenience, two image processing devices 2 are arranged on the internal network NT, but three or more image processing devices 2 may be arranged on the internal network NT. In the following description, when it is necessary to distinguish between two image processing devices 2, one image processing device 2 may be assigned the reference symbol 2A and referred to as a first image processing device 2A, and the other image processing device 2 may be assigned the reference symbol 2B and referred to as a second image processing device 2B.

[0014] The image processing device 2 generates image data and outputs the image data. The type of the image processing device 2 (in other words, the functions installed in the image processing device 2) is not particularly limited. The image processing device 2 may be a multifunction peripheral (MFP), a printer, or a facsimile.

[0015] The communication system 100 also includes a user terminal 3 as the communication device 10. The user terminal 3 is used by a user of the image processing device 2. The user terminal 3 is, for example, a personal computer. The user terminal 3 functions as, for example, an instruction device that instructs the image processing device 2 to print.

[0016] For example, there are multiple users of the image processing device 2. In this case, multiple user terminals 3 used by the multiple users are arranged on the internal network NT.

[0017] <Configuration of image processing device> As shown in Fig. 2, the image processing device 2 includes a printing unit 210. The printing unit 210 prints an image based on image data onto a sheet (in other words, outputs the image data). For example, the printing method of the printing unit 210 is an electrophotographic method. However, this is not limited to this. The printing method of the printing unit 210 may be an inkjet method.

[0018] The printing unit 210 forms a toner image. The printing unit 210 also transports a sheet toward the transfer nip. When the sheet being transported passes through the transfer nip, the printing unit 210 transfers the toner image onto the sheet.

[0019] Although not shown, the printing unit 210 includes a photoconductor drum and a transfer roller. The photoconductor drum carries a toner image on its peripheral surface. The transfer roller is in pressure contact with the photoconductor drum and rotates together with the photoconductor drum. The nip formed between the photoconductor drum and the transfer roller is the transfer nip.

[0020] The printing unit 210 includes a charging device, an exposure device, and a developing device. The charging device charges the peripheral surface of the photosensitive drum. The exposure device forms an electrostatic latent image on the peripheral surface of the photosensitive drum. The developing device develops the electrostatic latent image on the peripheral surface of the photosensitive drum into a toner image.

[0021] The image processing device 2 includes an image reading unit 220. The image reading unit 220 reads an original document and generates image data of the original document. If the image processing device 2 is a printer, the image processing device 2 does not need to include the image reading unit 220.

[0022] The image processing device 2 includes a control unit 20. The control unit 20 includes a control unit 21. The control unit 21 includes a processing circuit such as a CPU. The control unit 21 controls the image processing device 2. The control unit 21 operates based on a program and performs various processes.

[0023] The control unit 20 includes a main memory unit 22. The main memory unit 22 is a RAM. That is, the main memory unit 22 is a volatile memory unit. The main memory unit 22 serves as a working area for the control unit 21. Programs and data for operating the control unit 21 are read into the main memory unit 22 and expanded.

[0024] The control unit 20 includes an auxiliary storage unit 23. The auxiliary storage unit 23 is configured with a ROM, a HDD, etc. In other words, the auxiliary storage unit 23 is a non-volatile storage unit.

[0025] The auxiliary storage unit 23 stores a security program that causes the control unit 21 to operate as a security system. The control unit 21 operates based on the security program, thereby performing security countermeasure processing that is simpler than the security countermeasure processing performed by the security monitoring device 1.

[0026] The image processing device 2 includes a reception unit 30. The reception unit 30 receives settings and instructions from a user. The reception unit 30 is an operation panel installed in the image processing device 2. The operation panel has a touch screen. That is, the reception unit 30 has a touch screen as a display unit. The reception unit 30 displays software buttons for receiving the settings and instructions on the touch screen. The reception unit 30 also has hardware buttons for receiving the settings and instructions.

[0027] The control unit 21 controls the display operation of the reception unit 30. The control unit 21 recognizes the settings and instructions received by the reception unit 30. The control unit 21 performs processing according to the settings and instructions received by the reception unit 30.

[0028] The image processing device 2 includes a communication unit 40. The communication unit 40 includes a communication circuit, a communication memory, a communication interface, and the like. The communication unit 40 is communicatively connected to another communication device 10 arranged on the internal network NT via the internal network NT. The communication unit 40 is also communicatively connected to a security monitoring device 1 arranged on the internal network NT via the internal network NT.

[0029] The control unit 21 controls communication by the communication unit 40. The control unit 21 monitors communication by the communication unit 40 by operating based on a security program. As a security countermeasure process, the control unit 21 detects unauthorized access to its own device based on information such as a source address, a destination address, and a port number. When unauthorized access is detected, the control unit 21 blocks the unauthorized access.

[0030] <Packet threat detection> The security monitoring device 1 detects threats in packets transmitted from the outside to the internal network NT, and also detects threats in packets transmitted from the internal network NT to the outside.

[0031] However, the security monitoring device 1 does not detect threats in packets sent from one communication device 10 on the internal network NT to another communication device 10. For example, even if there is a cyber attack on the image processing device 2 from a user terminal 3 infected with malware, the security monitoring device 1 cannot detect it. In other words, the security monitoring device 1 can detect and block threats that invade the internal network NT from the outside, but cannot detect threats that have already invaded a user terminal 3 on the internal network NT.

[0032] Even if a cyber-attack is launched against the image processing device 2 from a user terminal 3 infected with malware, if the image processing device 2 can detect the cyber-attack, the cyber-attack can be blocked. However, because the security countermeasure processing performed by the image processing device 2 is simple, there are cases where the cyber-attack from the user terminal 3 infected with malware cannot be detected. For example, even if a packet containing a virus is transmitted from the user terminal 3 infected with malware to the image processing device 2, there are cases where the image processing device 2 cannot detect the virus contained in the packet.

[0033] In order to prevent such inconveniences from occurring, it is sufficient to equip the image processing device 2 with security countermeasure functions equivalent to those of the security monitoring device 1. However, the hardware resources of the image processing device 2 are limited, and there are cases in which the image processing device 2 cannot be equipped with security countermeasure functions equivalent to those of the security monitoring device 1.

[0034] Therefore, the security monitoring device 1 receives a packet analysis request from the image processing device 2. The security monitoring device 1 checks whether the packet requested for analysis is an attack packet for which security measures should be taken. Then, the security monitoring device 1 notifies the image processing device 2 of the inspection result.

[0035] Of the multiple image processing devices 2 on the internal network NT, the first image processing device 2a performs processing to request the security monitoring device 1 to analyze a packet. Specifically, the first image processing device 2a (its control unit 21) performs processing according to the flow shown in Fig. 3. In this configuration, the first image processing device 2A corresponds to the "first communication device." The user terminal 3 corresponds to the "other communication device."

[0036] In step S1, the first image processing device 2a inspects the packet received from the user terminal 3 and inspects the inspection target (its header). In other words, the first image processing device 2A performs security countermeasure processing. Then, the first image processing device 2A judges whether the protocol is enabled in the settings of the first image processing device 2A.

[0037] If the first image processing device 2a determines in step S1 that the protocol is not enabled, the process proceeds to step S2. In step S2, the first image processing device 2A discards the inspection target. In other words, the first image processing device 2A does not process the inspection target. For example, the inspection target may be filtered, and a received packet whose destination port is a port of an invalid service in the settings of the first image processing device 2A may be discarded. Also, the inspection target may be determined to be invalid and discarded by using an application that realizes processing similar to netfilter.

[0038] In step S1, if the first image processing device 2a determines that the protocol is valid, the process proceeds to step S3. In step S3, the first image processing device 2a detects whether the inspection target is an attack packet (i.e., a packet containing a virus). At this time, for example, the payload of the inspection target may be inspected.

[0039] In step S3, if the first image processing device 2a determines that the inspection target is an attack packet, the process proceeds to step S2. On the other hand, in step S3, if the first image processing device 2a determines that the inspection target is not an attack packet, the process proceeds to step S4.

[0040] Here, the security countermeasure processing performed by the first image processing device 2A is simple. Therefore, even if the first image processing device 2a judges that the inspection target is not an attack packet, there is a possibility that the inspection target is an attack packet. Therefore, the first image processing device 2a performs the process of step S4.

[0041] Specifically, in step S4, the first image processing device 2A stores the inspection target (i.e., the packet received from the user terminal 3) in the main storage unit 22. Then, the first image processing device 2A transmits a copy of the inspection target to the security monitoring device 1 (see FIG. 4).

[0042] By receiving a copy of the inspection target from the first image processing device 2A, the security monitoring device 1 determines that there is a packet analysis request from the first image processing device 2A. The security monitoring device 1 then inspects whether the inspection target is an attack packet for which security measures should be taken. The security monitoring device 1 also notifies the first image processing device 2A of the inspection result as to whether the inspection target is an attack packet or not.

[0043] The security monitoring device 1 is capable of more advanced threat detection than the first image processing device 2A. Therefore, even if the image processing device 2a judges that the inspection target is not an attack packet, the security monitoring device 1 may judge that the inspection target is an attack packet.

[0044] In step S5, the first image processing device 2A recognizes the contents of the inspection result received from the security monitoring device 1 (i.e., whether or not the inspection target is an attack packet). When the first image processing device 2A receives a notification from the security monitoring device 1 that the inspection target is an attack packet, the first image processing device 2A performs the process of step S6. When the first image processing device 2A receives a notification from the security monitoring device 1 that the inspection target is not an attack packet, the first image processing device 2A performs the process of step S7.

[0045] When the process proceeds to step S6, the first image processing device 2A discards the inspection target without processing the inspection target. Note that the inspection target is the packet held in the main storage unit 22. That is, in step S6, the packet held in the main storage unit 22 is discarded.

[0046] When the process proceeds to step S7, the first image processing device 2A performs packet processing (i.e., processing of the inspection target). The first image processing device 2A extracts data from the packet and passes it to an application specified in the header.

[0047] In this embodiment, the security monitoring device 1 can detect threats in packets transmitted and received on the internal network NT. As a result, if the packet received by the first image processing device 2A from the user terminal 3 is an attack packet that cannot be detected by the first image processing device 2A, the security monitoring device 1 can detect that the packet is an attack packet. This makes it possible to prevent the internal network NT from being exposed to threats due to packets transmitted and received on the internal network NT.

[0048] In addition, in this embodiment, an analysis request is made from the first image processing device 2A to the security monitoring device 1, so that even if the first image processing device 2A does not have sufficient hardware resources, advanced threat detection can be performed on packets sent to the first image processing device 2A.

[0049] Furthermore, in this embodiment, the first image processing device 2A detects whether the inspection target is an attack packet or not before transferring a copy of the inspection target to the security monitoring device 1 (step S3). When it is detected that the inspection target is not an attack packet, the first image processing device 2A transfers the inspection target to the security monitoring device 1 (step S4). On the other hand, when it is detected that the inspection target is an attack packet, the first image processing device 2A discards the inspection target without transferring a copy of the inspection target to the security monitoring device 1 (step S2). Note that the fact that the inspection target is an attack packet means that the user terminal 3 may be infected with a virus. If the user terminal 3 is infected with a virus, the internal network NT may be exposed to a threat.

[0050] However, the second image processing device 2B is not equipped with a function for detecting threats like the first image processing device 2A. Therefore, even if an attack packet is sent from a virus-infected user terminal 3, it cannot be detected as an attack packet. In this case, the second image processing device 2B may not operate normally or may be used illegally.

[0051] In order to prevent such inconvenience from occurring, when the first image processing device 2A detects that the inspection target is an attack packet, it transmits threat information regarding the attack packet (for example, information indicating that an attack packet has been received) to the security monitoring device 1. The security monitoring device 1 stores the threat information received from the first image processing device 2A. In this configuration, when there is a possibility that the user terminal 3 is infected with a virus, that is, when there is a possibility that the internal network NT is exposed to a threat, the threat information is stored in the security monitoring device 1. In other words, the threat information is information indicating that there is a possibility that the internal network NT is exposed to a threat.

[0052] In this configuration, the second image processing device 2B periodically checks whether threat information is stored in the security monitoring device 1. In other words, the second image processing device 2B periodically inquires of the security monitoring device 1 whether the internal network NT is exposed to a threat (see FIG. 5). This allows the second image processing device 2B to recognize that the internal network NT is (possibly is) exposed to a threat, even if the second image processing device 2B does not have a function for detecting threats like the first image processing device 2A.

[0053] For example, when threat information is stored in the security monitoring device 1, the second image processing device 2B suspends the acceptance of login requests to its own device via the internal network NT. Also, when threat information is stored in the security monitoring device 1, the second image processing device 2B suspends the acceptance of job execution requests (for example, print execution requests) to its own device via the internal network NT.

[0054] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 1. Security monitoring equipment 2A First image processing device (first communication device) 2B Second image processing device (second communication device) 3. User terminal (communication device) 100 Communication Systems NT Internal Network

Claims

1. A security monitoring device that monitors communications between an internal network and an outside network; A first communication device disposed on the internal network, When a packet is received from another communication device on the internal network, the first communication device holds the received packet as an object to be inspected and transfers a copy of the object to be inspected to the security monitoring device; the security monitoring device notifies the first communication device of an inspection result as to whether the received inspection target is an attack packet for which security measures should be taken; When the first communication device receives a notification from the security monitoring device that the inspection target is the attack packet, the first communication device discards the inspection target without processing the inspection target; When the first communication device receives a notification from the security monitoring device that the inspection target is not the attack packet, the first communication device processes the inspection target.

2. the first communication device detects whether the inspection target is the attack packet before transferring a copy of the inspection target to the security monitoring device; When the first communication device detects that the inspection target is the attack packet, the first communication device discards the inspection target without transferring a copy of the inspection target to the security monitoring device; The communication system according to claim 1 , wherein when the first communication device detects that the inspection target is not the attack packet, the first communication device transfers the inspection target to the security monitoring device.

3. When detecting that the inspection target is the attack packet, the first communication device transmits threat information regarding the attack packet to the security monitoring device; The communication system according to claim 2 , wherein a second communication device on the internal network, separate from the first communication device, periodically checks whether the threat information is stored in the security monitoring device.

4. The communication system according to claim 3 , wherein the second communication device is an image processing device that processes and outputs image data received from another communication device on the internal network.

5. The communication system according to claim 1 , wherein the first communication device is an image processing device that processes and outputs image data received from another communication device on the internal network.

Images