FR3008267A1 - DEVICE, SYSTEM AND METHOD FOR SECURING DATA TRANSFER BETWEEN PORTABLE SOURCE DATA STORAGE DEVICE AND COMPUTER SYSTEM TO RECEIVE - Google Patents

Abstract

The invention relates to a device for securing data transfer (8) between a source portable data storage device (4) and a destination computer system (6), comprising input connection means (10, 12) allowing the connection of the source storage device (4), and output connection means (10, 12) for connecting another portable data storage device (18), said intermediate storage device (18) and / or connection means (14, 14 ') directly to the destination computer system (6). This data transfer security device (8) comprises a unique identifier validation module associated with the source portable data storage device (4) connected at the input, at least one data security verification module to be transferred, capable of to apply at least one security check of the data to be transferred in case of positive validation of said identifier and a data transfer module, able to authorize one-way data transfer of the source portable data storage device (4) via the output connection means. The invention also relates to a data transfer security system and a method for securing the transfer of associated data.

Description

FIELD OF THE INVENTION The present invention relates to a device for securing the transfer of data between a source portable data storage device and a computer system. recipient, an associated data transfer security system and a method for securing the associated data transfer. The invention lies in the field of securing data exchanges from portable mass storage devices, such as in particular USB keys ("Universal Serial Bus"). The use of portable data storage devices, removable, able to be connected to a computer, and more generally to a computer system, via a universal serial bus or USB type connection, is becoming more common, including in the field of business and in the industrial field.

Thus, it is common for users to use this type of portable data storage device, including USB keys, to transfer data bi-directionally between computer systems of different security levels. Moreover, these data storage devices commonly host both personal data and professional data of the users.

As a result, such devices pose a threat to security, particularly when they are used to transfer data to so-called critical business computing systems, the security level of which must be high. The need to enable secure data transfers from a portable and removable data storage device to a high criticality information system is recognized. To meet this need, have been proposed antivirus verification systems, which verify by software, by heuristic analysis, that all the files stored on such a data storage device are secure, so do not contain code malicious program, able to perform intrusive actions in a recipient computer system. Such systems systematically use computational resources and only allow partial security, depending on the anti-virus verification system implemented. US2011 / 0088093-Al discloses a USB security connector device, which aims to prevent intrusion and spread of malware via a USB storage device. The connector device has two USB connection interfaces, one for the destination terminal, the other for the source USB storage device. The connector device contains software code capable of implementing security checks according to given security rules. However, there is a need to increase the security of data transfer, especially to a computer system requiring a higher level of security, such as a critical security company computer system. For this purpose, the invention proposes, according to a first aspect, a device for securing data transfer between a source portable data storage device and a destination computer system, comprising input connection means for connecting the device. source storage, and output connection means for connecting another portable data storage device, said intermediate storage device and / or means for direct connection to the destination computer system. The data transfer security device comprises: a unique identifier validation module associated with the source portable data storage device connected at the input, at least one data security verification module to be transferred, able to apply to the data transfer device; less a security check of the data to be transferred in the event of positive validation of said identifier, - a data transfer module, able to authorize a one-way data transfer of the source portable data storage device (4) via the means of data transfer. output connection. Advantageously, the device according to the invention makes it possible to verify an identifier of the source portable storage device prior to any security check, which makes it possible to increase security while saving the computing and energy resources, since no security check is provided. applied in the case where the extracted unique identifier is not validated. The device according to the invention may have one or more of the features below, taken independently or in combination.

The validation module is able to extract the unique identifier of the source portable data storage device and to validate the membership of said identifier to a set of identifiers pre-registered in a memory space of the data transfer security device. The data transfer security device comprises two data security verification modules to be transferred, a content security verification module and a file format security verification module.

The content security verification module is capable of applying at least one security check capable of verifying that a set of data to be transferred does not contain malicious code code that can harm the recipient computer system. The data to be transferred is stored in at least one file and the file format security check module is able to verify that the format of the file (s) containing the data to be transferred is part of a set of file formats recorded. The file format security verification module is furthermore able to check the consistency of the data to be transferred with the file format in which said data to be transferred is stored. The data transfer security device comprises a memory partition dedicated to the transfer of data, and the data transfer module is able to copy the data to be transferred from the source portable data storage device to said dedicated memory partition.

The data transfer module is able to control a deactivation of the input connection means, and an activation of the direct connection means to the destination computer system. The data transfer security device comprises a display screen adapted to display textual information.

The connection means of the source data storage device and the intermediate storage device are USB type connection means. According to a second aspect, the invention relates to a data transfer security system which comprises a data transfer security device as briefly described above and a set of at least two authorized portable data storage devices having each associated unique identifier, the unique identifiers of all authorized portable data storage devices being stored in a memory of the data transfer security device. According to a third aspect, the invention relates to a method for securing the transfer of data between a source portable data storage device and a destination computer system, implemented by a data transfer security device as briefly described below. thereon, comprising steps of: - validation of a unique identifier associated with the source portable data storage device, -in case of positive validation, application of at least one security check of the data to be transferred, -in case of result positive in the security verification step, transfer of the data to be transferred to a buffer, and - in the event of a negative result in the validation step or in the security verification step, blocking the transfer of the data to be transferred .

The process according to the invention may have one or more of the following characteristics, taken independently or in combination. The security verification step includes a content check of the data to be transferred and a file format check of the data to be transferred. According to a variant, the method comprises, after the transfer of the data to be transferred in a buffer memory, the steps of: -deconnecting the source portable data storage device, - validating a unique identifier associated with a storage device intermediate portable, - in case of positive validation, formatting a memory of the intermediate portable storage device and transferring the data to be transferred from said buffer to the intermediate portable storage device. According to a variant, the method comprises, after the transfer of the data to be transferred in a buffer memory, the steps of: deactivating a first connection interface making it possible to connect the source portable data storage device to the device for securing the transfer of data. data, -activation of a second connection interface for a connection of the data transfer security device to the destination computer system, - transfer of data to be transferred from said buffer to the destination computer system. The first connection interface is a USB type connection interface and the second connection interface is an Ethernet type connection interface. Other characteristics and advantages of the invention will emerge from the description given below, by way of indication and in no way limiting, with reference to the appended figures, among which: FIG. 1 is a schematic example of a system data transfer device implementing a data transfer security device according to the invention; FIG. 2 is a schematic example of a hardware configuration of a data transfer security device according to one embodiment of the invention; FIG. 3 is a block diagram of the main functional modules of a transfer security device according to the invention; FIG. 4 is a flowchart of the main steps of a method for securing data according to a first embodiment of the invention, and FIG. 5 is a flowchart of the main steps of a method of securing data according to a second embodiment of the invention. Figure 1 schematically illustrates a system 2 for transferring data stored on a source mass storage device 4 to a destination computer system 6, which is in this embodiment an enterprise network. Data transfer is via a data transfer security device 8 according to the invention, called simply transfer device thereafter. The transfer device 8 comprises two USB connection ports 10 and 12, also called USB connection interfaces, and a port or network connection interface 14, which is for example an Ethernet connection port, capable of receiving a cable 16 data transfer, provided with an RJ45 type connection, for transferring encapsulated data in transmission packets to the destination computer system 6. The USB connection port 10 is able to be connected to the source storage device 4 via a USB interface 20 of this device. Similarly, the USB connection port 12 is adapted to be connected to another USB portable storage device 18, which is an intermediate data storage device, via a USB connection interface 24 of this portable USB storage device 18 The data to be transferred is stored as one or more files stored in a memory 22 of the source storage device 4, the file format (s) authorized for the data transfer being known and stored in the transfer device 8. For example, for an application in the field of the supervision of industrial installations, the files to be transferred are in a predetermined SCADA format ("supervisory control and data acquisition"). For other uses (office automation for example), the system supports, for example, HTML, TXT, CSV. The transfer device has a plug-in system for taking into account new file formats. Thus, advantageously, the authorized file formats are not limited in number. The source storage device 4 also comprises a unique identifier IDs, which is preferably physically encrypted, for example using the AES encryption standard.

The intermediate storage device 18 also comprises a memory 26, as well as a unique identifier IDi, which is preferably physically encrypted, for example by using the AES encryption standard. The respective IDs and IDi IDs are integrated into the respective storage devices at the time of their manufacture and are non-modifiable. According to a first mode of use of the transfer device 8 according to the invention, the data to be transferred are extracted from the portable storage device source 4, and sent to the intermediate storage device 18. In this mode, the storage device 18 is first made reliable, so formatted, so as to ensure that it contains no malware code or malware in English terminology, which could infect the computer system recipient 6. In this mode of use, the Intermediate storage device 18 is then used in a conventional manner for the transfer of data to the destination computer system 6. According to a second mode of use of the transfer device 8 according to the invention, the data to be transferred are extracted from the storage device source 4, and sent to the destination system 6, via the network connection 14. In this mode of use, the transfer device 8 initially receives the data to be transferred and stores them in a dedicated memory partition, as explained hereinafter with reference to FIGS. 3 and 4. The transfer device 8 makes it possible to transmit data in one-way direction to the destination computer system 6, and after deactivation of the connection ports 10 and 12, in order to avoid any possible interaction between a communication via the USB ports 10 and 12 and a communication via the Ethernet port 14.. The transfer of the data is in one direction, thanks to a diode allowing the transfer of data from the transfer device to another device or to the destination computer system 6. FIG. 2 schematically illustrates a hardware configuration of a device for 8. This device comprises a housing 30 having, as connection interfaces, USB connection ports 10, 12 as well as Ethernet connection ports 14, 14 '. In the embodiment illustrated in FIG. 2, the transfer security device 8 has two Ethernet connection ports. In this case, an Ethernet port allows the configuration or the administration of the transfer device, or the taking into account of new options, and another port is connected to the interconnection network of the destination system 6 in the case of network use. .

Optionally, the transfer security device 8 comprises a display screen 32, LCD screen type, able to display textual information.

In addition, the transfer security device 8 comprises a central processing unit 34, or CPU, able to execute control program instructions when the device 8 is turned on, the instructions being transferred to a random access memory RAM 35. The transfer device 8 also comprises information storage means 36, capable of storing executable code instructions enabling the implementation of programs comprising code instructions capable of implementing the method of secure data transfer according to FIG. 'invention. As illustrated in FIG. 2, the information storage means are partitioned into several physical partitions 38, 40, thus making it possible to have a memory partition, for example the partition 38, dedicated to the transfer of data, and a another partition 40 for storing executable code and associated parameters. A first USB interface module 42 is connected to the USB connection ports 10, 12 and makes it possible to control the transfer of data via these connection ports. Thus, the connection ports 10, 12 and the interface module 42 constitute a first connection interface. In addition, the transfer device 8 comprises a network interface module 44, connected to the network communication ports 14, 14 '. Thus, the connection ports 14, 14 'and the network interface module 44 constitute a second connection interface. In this embodiment, the network interface module 44 is able to implement a communication according to the Ethernet protocol. Alternatively, any other network communication protocol may be implemented, the connection interfaces 14, 14 'being adapted if necessary in this case. The various functional blocks of the transfer device 8 described above are connected via a communication bus 45. FIG. 3 is a diagram illustrating the functional blocks of a data transfer security device 8. The transfer security device 8 comprises a unique identifier validation module 50. This module retrieves an identifier IDj from a portable mass storage device connected to one of the connection ports 10, 12 and compares it with a set of authorized identifiers {IDk}, stored in a memory storage space 52 of the means of storage. storage 36. Thus, the transfer security device 8 maintains a pool of authorized portable mass storage devices, which are identified by pre-recorded IDk IDs and stored in the device 8. The set of authorized identifiers {IDk} can be modified or updated only through programs transferred by a user with administrator rights, so a high privilege level, via a device connectable to the transfer security device 8, for example via an administrator USB key. Such an administrator USB key is identified by a cryptographic identifier in known manner. Preferably, the data contained on the administrator USB key is encrypted. In addition to the identifier validation module 50, the transfer security device 8 comprises two data control modules to be transferred, a content control module 54, and a file format control module 56. The module 54 is able to apply several antivirus-type content checks, but also "antimalware" that detect any malicious code introduced into the data files to be transferred and one or more "antispyware" type controls that detect any program codes able to subsequently retrieve data from the destination computer system. One or more software programs implementing this type of control are implemented by the content control module 54. Advantageously, the module 54 is able to perform several levels of checks, as much as necessary for a required level of security.

The module 56 is able to check the format of the data files to be transferred, a set of authorized file types being previously known and stored. In addition, this module is able to check the consistency between the file format of a file to be transferred and the contents of this file. For example, when a transfer of supervisory data of industrial installations is made, the data file format to be transferred is for example a SCADA format. Advantageously, the module 56 makes it possible to prohibit a copy of any type of file, and thus to better limit the risks of introduction of malware codes. In addition, validating the consistency of the content with the file type helps to better guard against possible attacks in which an authorized file format is simulated to conceal malware code. Each of the modules 54, 56 includes a plug-in system allowing the addition of additional controls such as obfuscation of files. In addition, it is possible to update the embedded software programs in the transfer security device 8 implemented by the modules 54 and 56 by transfer via an administrator USB key as described above. The transfer security device 8 also comprises a module 58 for copying the data file or files after security validation by the modules 54 and 56 in a memory space 38, called a buffer memory, intended for these data, and to control the transfer. of this data from the memory space 38 to one of the output connection interfaces 12 or 14, 14 '. The one-way transfer is physically guaranteed by the insertion into the electronic circuit of diodes that allow the transmission of data in one direction. In order to further improve the security of data transfer, a data transfer method according to the invention ensures that there is no direct communication between the source mass storage device 4 and the target, that it This is the intermediate mass storage device 18 or the destination computer system 6. The main steps of a data transfer security method according to a first embodiment, implemented by the processor 34 of the transfer security device 8 are described below with reference to FIG. 4.

In this first embodiment, data stored in one or more files of the source mass storage device 4 are transmitted to an intermediate mass storage device 18. During a first identification validation step 60 of the identifier IDs of the source mass storage device. During this step, the identifier IDs is obtained from the source mass storage device 4, it is decrypted according to an expected decryption algorithm, for example the AES algorithm, and it is compared to the set of IDk identifiers stored in a device. 8. If IDs is part of the set of identifiers previously stored, then it is deduced that the source mass storage device 4 is part of the authorized devices. Otherwise, the transfer is blocked (step 62). In the data transfer blocking step 62, the data temporarily copied to the memory of the transfer security device 8 is destroyed and the USB connection port is deactivated, thus preventing any data transfer, thus ensuring a transfer to the data transfer block. one way.

If the validation of the identifier is positive, step 60 is followed by a step 64 of content security control. A series of content security checks are performed, including anti-virus checks, antimalware checks, and antispyware checks. In an alternative embodiment, a single security check is applied, either an anti-virus check, an anti-malware check, or an antispyware check. In another embodiment, several antivirus checks according to different algorithms are applied. It should be noted that it is possible to add many other controls, thanks to a plug-in type of operation. Any known security content control algorithm is applicable at step 64.

In case of a negative result, so if one of the applied content security checks indicates the possibility of malware code present, the data transfer is blocked, so step 64 is followed by step 62 already described. In case of a positive result, so if all the content security checks are positive and thus indicate a lack of malware code, step 64 is followed by a file format check step 66. As already explained above, it is verified, for each data file to be transferred, that the file format is an authorized format, therefore is part of a set of authorized formats, and that the file data are consistent with the file format. file format. Such a consistency check is known per se and will not be described in more detail here. If the file format is not an authorized format or if it is an authorized format but a lack of coherence has been detected, step 66 is followed by step 62 of transfer blocking previously described data. If the file format check is positive, then if the file format is allowed and the data is consistent with the file format, then step 66 is followed by a step 68 of copying the one or more data files to transfer to a buffer. Advantageously, the copy 68 of the file or files to be transferred is authorized only if all the controls implemented during the steps 64, 66 are positive.

It should be noted that the order of steps 64, 66 can be reversed. Then, in a next step 70 a message is displayed on the display screen 32 requesting to disconnect the source mass storage device 4, so disconnect it by releasing the USB connection port to which it is connected. In step 72, after checking the release of the USB connection ports, a message is displayed on the display screen 32 requesting the user to connect a transfer mass storage device, or a storage device. intermediate mass. In a subsequent intermediate mass storage device identifier validation step 74, after verifying the presence of an active USB port connection, a validation similar to that of step 60 is performed: an IDi identifier is extracted from the intermediate mass storage device and it is verified that it belongs to all the identifiers previously stored, so that it is one of the authorized mass storage devices. Then during a formatting step 76, the memory of the intermediate mass storage device is formatted, so any data that may be present is erased. It should be noted that such formatting does not erase the unique identifier IDi of the intermediate mass storage device, which is stored at the hardware or "hardware" level. As a variant, it is verified during step 76 that the memory of the intermediate mass storage device has been formatted Finally, during a data transfer step 78, the data are copied from the buffer memory to the memory of the memory device. intermediate mass storage device. The main steps of a method for securing data transfer according to a second embodiment, implemented by the processor 34 of the transfer security device 8 are described below with reference to FIG.

In this second embodiment, data stored in one or more files of the source mass storage device 4 are transmitted, in a one-way transfer, to the destination computer system 6. Steps 60 to 68 are similar to the steps of the same references and described with reference to Figure 4, so they are not described again here.

In the case of positive validation of the security controls, step 68 is followed by a step 80 of deactivating the USB connection ports, in which the USB connection port (s) 10, 12 are deactivated. This deactivation is done via the USB interface module 42, according to the operating system implemented on the device for securing the transfer data 8. In one embodiment, it is the system of exploitation based on a UNIX / Linux kernel. Optionally, during a step 82, a message requesting the disconnection of the source mass storage device is displayed on the display screen 32. Then, during a network activation step 84, the interfaces or ports network connection 14, 14 'are activated.

The file or files are then transferred via the network connection to the destination computer system during a transfer step 86. Once the transfer is made, the network connection interfaces 14, 14 'are deactivated during a step 88, and the ports 10, 12 of USB connection are reactivated during a step 90.

Thus, the USB and network connection interfaces are not active at the same time, thus avoiding creating a security flaw during transfers. Preferably, indications are displayed on the display screen 32 at each step, in order to inform the user of the progress of the process.

Claims (16)

CLAIMS1.- Device (8) for securing the transfer of data between a source portable data storage device (4) and a destination computer system (6), comprising input connection means (10, 12) for connection the source storage device (4), and output connection means (10, 12) for connecting another portable data storage device (18), said intermediate storage device (18) and / or connection means (14, 14 ') directly to the destination computer system (6), the data transfer security device (8) being characterized in that it comprises: a validation module (50) of unique identifier associated with the source portable data storage device (4) connected at the input, - at least one data security verification module (54, 56) to be transferred, able to apply at least one security control of the data to be transferred e n case of positive validation of said identifier, - a data transfer module (58), able to authorize a one-way data transfer of the source portable data storage device (4) via the output connection means. 2.- Device according to claim 1, characterized in that the validation module (50) is adapted to extract the unique identifier of the source portable data storage device (4) and to validate the membership of said identifier to a set identifiers pre-registered in a memory space (52) of the data transfer security device (8). 3. -Dispositif according to one of claims 1 or 2, characterized in that it comprises two data security verification modules to be transferred, a content security verification module (54) and a security verification module of file format (56). 4.- Device according to claim 3, characterized in that the content security verification module (54) is adapted to apply at least one security check capable of verifying that a set of data to be transferred does not contain a security code. malicious program likely to harm the recipient computer system. 5.- Device according to one of claims 3 or 4, characterized in that the data to be transferred are stored in at least one file and in that the file format security verification module (56) is able to verify the format of the file or files containing data to be transferred is part of a set of pre-registered file formats. 6.- Device according to claim 5, characterized in that the file format security verification module (56) is further able to verify a consistency of the data to be transferred with the file format in which said data to be transferred are stored. 7.- Device according to one of the preceding claims, characterized in that it comprises a memory partition (38) dedicated to the transfer of data, and in that the data transfer module (58) is able to copy the data transferring from the source portable data storage device (4) to said dedicated memory partition (38). 8.- Device according to claim 7, characterized in that the data transfer module (58) is adapted to control a deactivation of the input connection means, and an activation of the connection means (14, 14 ') direct to the destination computer system (6). 9.- Device according to one of the preceding claims characterized in that it comprises a display screen (32) adapted to display textual information. 10.- Device according to one of the preceding claims characterized in that the connection means of the source data storage device and the intermediate storage device are USB type connection means. 11. A data transfer security system characterized in that it comprises a device (8) for securing data transfer according to one of claims 1 to 10 and a set of at least two storage devices (4). , 18) of authorized portable data each having a unique identifier (IDs, IDi) associated therewith, and in that the unique identifiers of all authorized portable data storage devices are stored in a memory (52) of the device (8) of secure data transfer. 12. - Method for securing data transfer between a source portable data storage device (4) and a destination computer system (6), implemented by a device (8) for securing the transfer of data according to one of the claims 1 to 10, characterized in that it comprises steps of: - validation (60) of a unique identifier associated with the source portable data storage device (4), -in case of positive validation, application of at least one security check (64, 66) of the data to be transferred, -in case of a positive result in the security check step (64, 66), transfer (68) of the data to be transferred to a buffer memory, and in the event of a negative result in the validation step (60) or in the security verification step (64, 66), blocking (62) the transfer of the data to be transferred. 13. A method according to claim 12, characterized in that the security verification step (64, 66) comprises a content verification (64) of the data to be transferred and a file format check (66) of the data to to transfer. 14.- Method according to one of claims 12 or 13, characterized in that it comprises, after the transfer (68) of the data to be transferred to a buffer memory, the steps of: -question (70) of disconnection of the device source portable data storage, - validation (74) of a unique identifier associated with an intermediate portable storage device, - in case of positive validation, formatting (76) of a memory of the intermediate portable storage device and transfer ( 78) data to be transferred from said buffer to the intermediate portable storage device. 15.- Method according to one of claims 12 or 13, characterized in that it comprises, after transferring the data to be transferred to a buffer memory, the steps of: -deactivation (80) of a first connection interface for connecting the source portable data storage device to said data transfer security device, -activation (84) of a second connection interface for a connection of the data transfer security device to the destination computer system, - transfer ( 86) data to be transferred from said buffer to the destination computer system. 16. The method of claim 15, characterized in that said first connection interface is a USB type of connection interface and in that said second connection interface is an Ethernet type of connection interface.