JP2007286905A - Information processing terminal device, file leakage prevention method, and file leakage prevention program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information processing terminal device, a file leakage prevention method, and a file leakage prevention program for preventing unwanted transfer of a file not intended by a user via a network to prevent information leakage. <P>SOLUTION: This information processing terminal device takes over access to a file from an application 01 to determine whether the access is made by an application usually used or not by a file-application relationship analysis means 05, and based on the determination result, a file usage permission determination means 04 controls file access. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an information processing terminal device, a file outflow prevention method, and a file outflow prevention program for preventing file outflow, and more particularly, software such as a virus is used to transfer a file to a computer unintended by the user through a network. The present invention relates to an information processing terminal device, a file outflow prevention method, and a file outflow prevention program that can prevent transfer.

  Conventionally, “personal firewall technology” that prevents a file from leaking and “file encryption technology” that makes the file unusable even if the file leaks are widely known as file leakage prevention technologies. Hereinafter, these techniques will be described.

(1) Personal firewall technology This is a technology for preventing files from leaking from a computer via a network. Usually, in order for a computer to communicate via a network, an address that identifies the computer on the network and a number that identifies software that communicates within the computer are used. For example, in TCP / IP which is the most widely known communication method, the former is called an IP address and the latter is called a port number. In particular, the port number includes a number reserved in advance such as 25 for mail transmission and 80 for WWW, and a number that can be freely used by the user program. This personal firewall technology is software that can be restricted in use by a combination of an IP address and a port number. For example, No. 25 and No. 80 can be set to communicate with a certain IP address. As a result, it is possible to stop illegally leaking a file using a port number for which a virus or the like is not reserved.

(2) File encryption technology This is a technology that eliminates actual harm when a file leaks by making the file unusable without decryption of a regular procedure. Encryption software is already very widely known, for example, software that automatically encrypts a hard disk and software that encrypts files. As one of file encryption software, digital rights management technology (Digital Rights Management: hereinafter referred to as DRM) is often used. This DRM encrypts original data by a secret code method. This encrypted data is called a capsule, and the capsule cannot be used unless it is decrypted. That is, the use of this data requires a decryption key for decrypting the capsule. A person who has been granted the use authority can use this data by authenticating by some method, obtaining a decryption key, and returning to normal data immediately before use. DRM is generally used to prevent illegal duplication of multimedia information such as movies and music, but it is also effective for so-called office texts created with word processors and spreadsheet software. Yes. For example, by encapsulating accounting information files that can only be used by executives with DRM, and giving only the executives a decryption key that decrypts this capsule, it is possible to protect confidential information from other employees and those outside the company. Become.

  The personal firewall has a problem that recent viruses cannot prevent file leakage. A recent virus searches for a port in a communicable state, and performs communication using this port. For example, in a computer using the WWW, No. 80 can be used, and the virus automatically sends a local file to a network destination computer using this port. If this port is blocked, the WWW cannot be used and cannot be blocked. In other words, if there is an application that uses some kind of network, the file can be leaked using the port used by this application.

On the other hand, the above file encryption technology cannot prevent the outflow of files for the following reasons.
(1) I forgot to encrypt. File encryption is a hard process for a computer, and only important sentences are encrypted. However, this is not thorough with user operation. In other words, there are important files that are not encrypted.
(2) There are applications that cannot perform file-by-file encryption. For example, an electronic mail message can be encrypted in the communication path, but the state stored in the local computer is plain text. Technically, it is possible to send encrypted e-mail text, but forgetting to encrypt it occurs. In the first place, encryption of the body of an email is not widespread at all.
(3) There is a user who does not encrypt for convenience. Encryption and decryption require authentication processing, and are inconvenient in that they cannot be used without being connected to a network. This makes it difficult to ensure thorough encryption.

  The present invention has been made in view of the above circumstances, and prevents information leakage by preventing a file connected by the user from being transferred via the network in a computer connected to the network. It is an object to provide an information processing terminal device, a file outflow prevention method, and a file outflow prevention program.

  In order to achieve such an object, the invention described in claim 1 is common to an application that is software that provides a predetermined service to a user and an application software in an information processing terminal device having a communication function via a network. An operating system, which is software that provides basic functions to be used as an operating system, an operating system usage hook means that detects use of the operating system from an application, and a file that is detected by the operating system usage hook means as a file, Based on the determination result of the file application relation analyzing means for determining the application to be used and the file application relation analyzing means, the operating system using hook means detects And file use permission determination means for controlling access was, characterized by comprising a.

  According to a second aspect of the present invention, in the first aspect of the invention, the file application relationship analyzing means includes a file type application correspondence table describing a correspondence relationship between a file type and an application normally used by the file, and an operating system. File application relation determining means for determining whether or not the file is accessed by a normally used application based on the attribute information of the file detected by the use hook means and the file type application correspondence table. It is characterized by that.

  The invention according to claim 3 is the invention according to claim 2, wherein the file type application correspondence table includes a correspondence between an extension of a file name and an executable file name of an application normally used by the file. .

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein when a file access other than a normal application is made, the user interactively permits the file access or A file permission dialogue means for selecting whether to prohibit is further provided.

  In the invention described in claim 5, in the invention described in claim 4, when the user permits the file access other than the normal use application by using the file permission dialogue means, the access is made when there is a similar access thereafter. The file type application correspondence table updating means for updating the file type application correspondence table to allow the file type application correspondence table is further provided.

  The invention according to claim 6 is the invention according to claim 4 or 5, wherein the file permission dialogue means allows the user to set a valid period for permitting predetermined file access, and the valid period is set in the file type application correspondence table. It is characterized by being reflected.

  The invention according to claim 7 is the invention according to any one of claims 4 to 6, further comprising an access prohibition log that records a result input by a user through the file permission dialogue means. .

  The invention according to claim 8 is an application that is software that provides a predetermined service to a user, an operating system that is software that provides basic functions commonly used by the application software, and a communication function via a network. A file outflow prevention method executed by an information processing terminal device comprising: an information processing terminal device that uses a function provided by an operating system when a user uses a predetermined application. In addition, an API call step for calling a system call that is disclosed to the application by the operating system, and between the application and the operating system, the file system is called in the call of the system call. The API call hook step that intercepts the file, and the information of the application that is trying to access the file from the system call parameters related to the file system that was intercepted in the API call hook step, and the file information are extracted. File application relation analysis step that determines whether access is from the application to be executed, file application relation analysis step, file usage branch step that switches processing depending on whether or not access to the file is permitted, and file usage When it is determined that it can be used in the branch step, the system call intercepted in the API call hook step is recalled to the operating system. And API recall step of, characterized by a run.

  The invention according to claim 9 is the invention according to claim 8, wherein the information processing terminal device includes a file type determining step for determining the type of the accessed file and a file type determining step in the file application relation analyzing step. Normal use application determination that determines whether the accessed file is a normal use application based on the file type application correspondence table that describes the correspondence between the determined file type and the application that the file normally uses A step of comparing the normal use application determined in the normal use application determination step with the application to be actually accessed, and executing a file availability determination step of determining availability. That.

  The invention described in claim 10 is the interactive screen display step in which the information processing terminal device displays a screen for selecting whether to permit or prohibit access interactively in the invention according to claim 8 or 9, User access right setting step in which whether to permit or prohibit access is input by the user on the screen displayed in the interactive screen display step, and user access for branching the operation based on the result of the user access right setting step And a right setting branching step.

  The invention described in claim 11 is the information processing terminal device according to any one of claims 8 to 10, wherein the information processing terminal device includes an access permission file type determination step for determining a file type to which file access permission is granted, and an access permission file type determination step. And a file type application correspondence table update step for updating the file type application correspondence table based on the result of the above and the application name input by the user on the screen displayed in the interactive screen display step. And

  The invention according to claim 12 is the invention according to any one of claims 8 to 11, wherein the information processing terminal device performs a step between the file type determination step and the normal use application determination step in the file application relationship analysis step. In addition, a period narrowing step for narrowing down the file type application correspondence table based on period information for permitting access is further performed.

  The invention according to claim 13 is the invention according to any one of claims 10 to 12, wherein the information processing terminal device is input by the user between the user access right setting step and the user access right setting branching step. An access prohibition log adding step for leaving the set file access permission in the log is further executed.

  The invention according to claim 14 is an application that is software that provides a predetermined service to a user, an operating system that is software that provides basic functions commonly used by the application software, and a communication function via a network. A file outflow prevention program for causing an information processing terminal device to execute a file outflow prevention method, and when the user uses a predetermined application for the information processing terminal device, the application is provided by the operating system. API call processing that calls the system call that the operating system discloses to the application when using the function to be performed, and the system call is called between the application and the operating system The API call hook process that intercepts the call related to the file system and the information of the application that is trying to access the file and the file information are extracted from the parameter of the system call related to the file system that is intercepted by the API call hook process. File application branch analysis process that determines whether or not a file is an access from an application that is normally used, and a file application branch process that switches the process depending on whether or not there is permission to access the file as a result of the file application relation analysis process When it is determined that the file can be used in the file usage branch process, the system call intercepted in the API call hook process is recalled to the operating system. And API recall processing for issuing, characterized in that to the execution.

  A fifteenth aspect of the present invention is the file type determination process according to the fourteenth aspect of the present invention, in which the information processing terminal device performs a file type determination process and a file type determination process for determining the type of file accessed in the file application relation analysis Normal use application determination that determines whether the accessed file is a normal use application based on the file type application correspondence table that describes the correspondence between the determined file type and the application that the file normally uses And a file use determination process for determining the availability by comparing the normal use application determined in the normal use application determination process with the application that is actually being accessed. .

  The invention according to claim 16 is the interactive screen display process according to claim 14 or 15, wherein the information processing terminal device displays a screen for selecting whether to permit or prohibit access interactively by the user. User access right setting processing in which whether to allow or prohibit access by the user on the screen displayed in the interactive screen display processing, and user access for branching the operation based on the result of the user access right setting processing And a right setting branch process.

  The invention according to claim 17 is the invention according to any one of claims 14 to 16, wherein an access permission file type determination process for determining a file type to which file access permission is given to the information processing terminal device; File type application correspondence table update processing for updating the file type application correspondence table based on the result of the access permission file type determination processing and the application name input by the user on the screen displayed in the interactive screen display processing; Furthermore, it is made to perform.

  According to an eighteenth aspect of the present invention, in the invention according to any one of the fourteenth to seventeenth aspects, the information processing terminal device performs a process between the file type determination process and the normal use application determination process in the file application relation analysis process. Further, a period narrowing process for narrowing down the file type application correspondence table based on the period information for permitting access is further executed.

  According to a nineteenth aspect of the present invention, in the invention according to any one of the sixteenth to eighteenth aspects, a user inputs an information processing terminal device between a user access right setting process and a user access right setting branch process. Further, an access prohibition log adding process for leaving the file access permission setting in the log is further executed.

  According to the present invention, it is possible to prevent information leakage by preventing a computer connected to a network from transferring a file that is not intended by the user via the network.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

Embodiment 1 of the present invention will be described in detail with reference to the drawings.
<Description of configuration>
The information processing terminal device according to the present embodiment is an information processing terminal device such as a personal computer, and prevents files that are not intended by the user from being transferred via the network on a computer connected to the network. , Can prevent information leakage.

  As shown in FIG. 1, the information processing terminal device according to the present embodiment includes an operating system (OS) 03, which is software that provides basic functions such as file management and user interface of a computer used by a user, a word processor, a mailer, and the like. , An application 01 that is software for a user to receive a service from a computer, an operating system utilization hook unit 02 that enters between the operating system 03 and the application 01 and detects the use of the operating system 03 from the application 01, With respect to a file whose access is detected by the system use hook unit 02, a file-application relationship analysis unit 05 for determining an application normally used by the file; Yl - a file use permission determination means 04 for operating system use hooking means 03 with the application related analysis means 05 controls the file access has been detected, and a. In addition, the information processing terminal device according to the present embodiment includes a communication function via a network.

  Further, as shown in FIG. 2, the file-application relationship analyzing unit 05 has a file type-application correspondence table 0502 describing the correspondence between the file type and the application normally used by the file. Further, the file-application relationship analyzing unit 05 accesses the file by a normal use application from the attribute information such as the file name of the file detected by the operating system use hook unit 02 and the file type-application correspondence table 0502. File-application relationship determining means 0501 for determining whether or not

Details of each means will be described below.
The application 01 is software that creates, browses, and edits confidential information such as word processors and spreadsheet software. For example, commercially available software such as a Microsoft office may be used.

The operating system 03 is software that provides the basic functions of a computer, provides an interface with a user such as a GUI, and manages a file system. The operating system 03 exposes its functions to the application 01 using a function group called API (Application Program Interface) as an interface. That is, the application 01 can use the function of the operating system 03 by calling this API.
The implementation of the operating system 03 may be performed by using widely known Windows (registered trademark), UNIX (registered trademark), or the like.

The operating system utilization hook unit 02 is a unit for the application 01 to detect an API call related to a file of the operating system 03. For example, when a file is used, first, an OPEN command that is an API for opening a file is called. The operating system utilization hook means 02 detects this OPEN command. Normally, API calls have arguments such as file names. The operating system utilization hook unit 02 also detects an argument such as a file name when detecting a command call.
The operating system utilization hook means 02 may be realized by using a function called “hook” provided in the operating system 03 as a standard. “Hook” is a mechanism in which an external program intercepts an event occurring in an application and an API call of the operating system by the application. In the case of Windows (registered trademark), an MSAA (Microsoft Active Accessibility) that acquires GUI operations, a message hook that acquires an event occurring in the application, and an API that acquires a system call from the application to the OS. A hook or the like is disclosed. In this embodiment, file access can be detected by using an API hook. The API hook can intercept API calls other than file access. Since only the file access is required in the present embodiment, the operating system utilization hook means 02 needs to store the name of the file access API and ignore the API call that is not the file access.

The information that can be intercepted by the API hook is as follows.
Application name: The name of the application that calls the API of the operating system API command name: The name of the API of the called operating system API command argument data: Data of the argument of the API of the called operating system

  Also, the API hook is intercepted immediately before the operating system call. That is, this API call will fail if it remains preempted. In order to succeed, the intercepted API call must be called back into the operating system.

An example of the file type-application correspondence table 0502 is shown in FIG.
File type (T050201): A field for classifying a file into several types and setting its classification code. In the example of FIG. 3, the files are classified by the extension of the file name, and the extension is described as a classification code.
Normal use application (T050202): A field describing an application used as a standard for each file type. Although the execution file name of the application is described in the example of FIG. 3, any description may be used as long as the application can be specified. Usually, in the operating system, one normally used application is defined according to the file type, and this definition may be used as it is or may be used by appropriately changing the definition.

  In the example of the first record in FIG. 3, the file with the extension DOC is MS-WORD. This means that an application with an executable file name of EXE is normally used.

  The file-application relationship determining unit 0501 obtains the application name and file name related to the file access detected from the file use permission determining unit 04, and the file currently focused on is determined from the file name and the file type-application correspondence table 0502. Then, it is determined whether or not the application is accessed from a normal application (for a specific determination method, refer to the file-application relationship analysis step in <Description of operation> described later).

The file use permission determination unit 04 receives the following information from the operating system use hook unit 02.
Application name: Application name detected by operating system utilization hook means 02 API command name: API command name detected by operating system utilization hook means 02 API command argument data: API command argument data detected by operating system utilization hook means 02

  First, a file name is detected from API command argument data. The number of the argument is the file name for each API command. For example, in the case of an OPEN command, the first argument is a command name. That is, the file usage permission determining unit 04 may store in advance what number of arguments is the file name for each command, and extract the value of the argument as the file name.

  The file use permission determination unit 04 passes the application name sent from the operating system use hook unit 02 and the extracted file name to the file-application relationship determination unit 05, and determines whether the access is from a standard application. Get it. If it is a standard application, this access is made successful by recalling the API command from the operating system utilization hook means 02 to the operating system 03. If it is not a standard application, this access is prohibited by not recalling the API command from the operating system utilization hook means 02 to the operating system.

For example, in the case of the above example, “WORDDPAD.EXE” is received as the application name from the file usage permission determination unit 04 and “sales.DOC” is received as the file name, and in the case of the file type-application correspondence table of FIG. -Since the application relationship determination unit 05 is determined to be an access from an application that is not a normal use application, the file use permission determination unit 04 calls an API call intercepted by the operating system use hook unit 02 to the operating system 03. Absent.
As a result, this access is prohibited.

<Description of operation>
The operation (file outflow prevention method) of the information processing terminal device of this embodiment will be described with reference to the flowchart of FIG. The information processing terminal device according to the present embodiment executes the file outflow prevention method described below under the control of the file outflow prevention program (the same applies to Examples 2 to 5).

  In FIG. 4, an application use step S01 in which a user uses an application such as a word processor, and an API call step S02 in which the OS calls a system call disclosed to the application when the application uses a function provided by the OS. An API call hook step S03 that intervenes between the application and the OS and intercepts a file system call in a system call call, and attempts to access the file from the system call parameter intercepted in the API call hook step S03. Application information and file information are extracted, and it is determined whether the access to this file is from a normal application. As a result of executing the file-application relationship analysis step S04 and the file-application relationship analysis step S04, in the file use branch step S05 and the file use branch step in which processing is switched depending on whether or not there is permission to access the file, An API recall step S06 for recalling the system call intercepted in the API call hook step to the OS when it is determined that it can be used.

  The application use step S01 is a step in which the user uses various functions of the application. Here, the application is not particularly limited. It may be a GUI application such as a word processor, a virus scan application that does not interact with the user, or a command such as UNIX (registered trademark).

  The API call step S02 is a step in which the application uses an OS system call. Normally, applications provide services to users by using various functions disclosed by the OS. For example, when reading and writing to a file, system calls such as “open file”, “read file”, “write to file”, and “close file” provided by the OS file system are called.

  The API call hook step S03 is a step in which the application 01 detects an API call related to the file of the operating system 03 by using the “hook” function of the OS as described in the operating system use hook unit 02. The information that can be intercepted in the API call hook step S03 is the application name, API command name, and API command argument data as described in the operating system utilization hook means 02.

Details of the operation of the file-application relationship analysis step S04 are shown in FIG.
File type determination step S0401: The file-application relationship determination unit 0501 extracts the extension of the file name from the API command argument data sent from the API call hook step, and sets this extension as the file type.
Normal use application determination step S0402: The file-application relationship determination unit 0501 matches the file name extension sent from the file type determination step S0401 with the file type field in the file type-application correspondence table 0502. It is assumed that the value of the field of the normal use application of the matched record is the normal use application for file access that pays attention.
Note that this matching does not always match. If it does not match the file type of any record, it is determined that the access is from an application that is not a normally used application, and the processing of the file-application relationship analysis step S04 is terminated.
File availability determination step S0403: The file-application relationship determination unit 0501 compares the application name of the normal usage application determination step S0402 with the application name sent from the API call hook step S03. If it is different, access is prohibited.

For example, the case of the file type-application correspondence table of FIG. 3 will be described with “WORDPAD.EXE” as the application name and “sales.DOC” as the file name from the API call hook step.
When the file-application relationship determination unit 0501 checks the file type field (T050201) of the file type-application correspondence table using the file name extension “DOC” as a key, the first record is searched. Next, the value “MS-WORD.EXE” of the normal use application (T050202) of the first record is compared with the application name “WORDDPAD.EXE” received from the file use permission judging means 04, and this access is different because the value is different. Is forbidden.

  File usage branching step S05: When access permission is sent from the file-application relationship analysis step S04 (step S05 / permission), the API recall step S06 is processed. If access prohibition is sent (step S05 / prohibition), the process is terminated. That is, the application has not been notified of this system call to the OS, and access is denied.

  API recall step S06: The system call from the application 01 to the OS 03 succeeds by recalling the system call taken in the API call hook step S03 to the OS.

Next, a second embodiment of the present invention will be described in detail with reference to the drawings.
<Description of configuration>
In this embodiment, as shown in FIG. 6, in the configuration of the first embodiment (FIGS. 1 and 2), when file access is prohibited by the file use permission determining unit 04, whether to permit interactively with the user / A file permission dialogue means 06 for selecting whether to prohibit is added.

An example of the screen of the file permission dialogue means 06 is shown in FIG.
Application name (U0601): The application name sent from the operating system utilization hook means 02 stored in the file utilization permission judgment means 04.
File name (U0602): File name sent from the operating system utilization hook means 02 stored in the file use permission judgment means 04 This time permission button (U0603): The user inputs that only the current access is permitted Button Prohibit button (U0604): Button for prohibiting access. Sales with an application called EXE. An attempt to access the DOC is prohibited.

  The file permission dialogue means 06 is called from the file use permission judgment means 04, and at this time, the data intercepted by the operating system use hook means 02, that is, the application name, API command name, and API command argument parameters are transferred. The file permission dialogue means 06 uses these transferred data to make an API to the OS in the same manner as the file use permission judgment means 04 when the user selects “permit this time (U0603)”. Execute the call.

<Description of operation>
In this embodiment, as shown in FIG. 8, in addition to the operation of Embodiment 1 (see FIG. 4), an interactive screen display step S07 for displaying a screen for selecting whether to permit or prohibit interactively with the user; The user access right setting step S08 for inputting whether the user permits or prohibits access on this screen, and the user access right setting branch step S09 for branching the operation from the result of the user access right setting step S08 Add to.

  In the interactive screen display step S07, when the file use branch step S05 is prohibited (step S05 / prohibited), the processing is ended in the first embodiment, but in the present embodiment, the interactive screen display step S07 is processed. Change to The dialog screen display step S07 displays the file permission dialog means 06 (screen shown in FIG. 7).

  The user access right setting step S08 is a step in which the user inputs either the “permit button (U0603) this time” or the “prohibit button (U0604)” of the file permission dialogue means 06.

  In the user access right setting branch step S09, when the “prohibit button (U0604)” is pressed in the user access right setting step S08 (step S09 / prohibited), the process is terminated, and “this time permit button (U0603)”. "Is pressed (step S09 / permitted), the API recall step S06 is processed.

Next, Embodiment 3 of the present invention will be described in detail with reference to the drawings.
<Description of configuration>
In the present embodiment, as shown in FIG. 9, in the configuration of the second embodiment (see FIG. 6), the file permission dialogue means 06 can be set to permit file access permanently thereafter “Allow in the future (U0605). When the user selects “Allow in the future (U0605)”, the file type / application correspondence table updating unit 07 for updating the file type / application correspondence table 0502 is added to the configuration.

A screen example of the file permission dialogue means 06 is shown in FIG.
The items added to FIG. 7 are as follows.
Allow button in future (U0605): Sets that a file of the same type as the file indicated by the file name is allowed to be accessed from the application indicated by the application name in the future.

  The file type-application correspondence table updating unit 07 is called when the “permit button (U0605)” is selected in the file permission dialogue unit 06, receives the application name and the file name from the file permission dialogue unit 06, The file type-application correspondence table 0502 is updated.

  For example, the file type-application correspondence table 0502 is shown in FIG. 3, and when the application name is “WORDDPAD.EXE” and the file name is “sales.DOC” as shown in FIG. 10, a record is added as shown in FIG. (For this additional method, see <Description of Operation> described later).

  If the file type values overlap in this way, a plurality of records may be matched by the matching in the file-application relationship determining unit 0501. In this case, the number of normally used applications is not one, but all matched records are handled. In the file availability determination step S0403, if any of the accessed applications has the same name, access is permitted. Remodel.

  As described above, in this embodiment, the file type-application correspondence table 0502 is updated, and the matching method of the file-application relationship determination unit 0501 is modified, so that setting to permit file access permanently can be performed thereafter. .

<Description of operation>
In the present embodiment, as shown in FIG. 12, in the operation of the second embodiment (see FIG. 8), an access permission file type determination step S10 for determining a file type to which file access permission is granted, and an access permission file type determination. A file type-application correspondence table update step S11 for updating the file type-application correspondence table 0502 is added from the result of step S10 and the application name transferred from the file permission dialogue means 06. That is, in this embodiment, when the “permit button (U0603) this time” is pressed in the user access right setting step S08 (step S09 / permission), the access permission file type determination step S10, file type-application correspondence Table update step S11 is processed in order.

In the access permission file type determination step S10, the file name is received from the file permission dialogue means 06, and the file type is determined from this extension.
For example, in the case of FIG. DOC is the file name, and the extension is DOC.

In the file type / application correspondence table update step S11, one record of the file type / application correspondence table 0502 is added, the following values are set, and the API recall step S06 is processed.
File type-file type in application correspondence table 0502 (T050201): file type in the access-permitted file type determination step S10. In the case of FIG. 10, DOC.
Normal use application (T050202) in the file type-application correspondence table 0502: the application name received from the file permission dialogue means 06. In the case of FIG. EXE.

Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings.
<Description of configuration>
In this embodiment, as shown in FIGS. 13 and 14, in the configuration of the embodiment 3 (see FIGS. 10 and 11), the file permission dialogue means 06 can be set to have a period for granting file access permission. The period input field (U0606) is added, the period field (T050203) is added to the file type-application correspondence table 0502, and the file-application relationship updating unit 07 also updates the period field (T050203). Remodel to

An example of the screen of the file permission dialogue means 06 is shown in FIG.
Items added to FIG. 10 will be described below.
Period (U0606): A period for granting access is set. In the example of the figure, for the sake of simplicity, only the last date allowed is set. However, the start date and the last date may be set, or may be set in the calendar user interface. .

FIG. 14 shows a file type / application correspondence table 0502.
The fields added to FIG. 11 will be described below.
Period (T050203): This correspondence table indicates a valid period. Always valid if left blank. In the example of FIG. 14, the first and second records are always valid, and the third record is valid up to 2006/10/26.

Along with this remodeling, the file-application relationship determining unit 0502 first narrows down to a set of valid records from the current time, and proceeds with processing on this table.
In the example of FIG. 14, when processing is performed after 2006/10/26, the third record is excluded from the search target (for details, refer to <Description of operation> described later).

  The file type / application correspondence table updating unit 07 receives the data of the period from the file permission dialogue unit 06 and modifies it so as to store it in the period of the file type / application correspondence table 0502.

<Description of operation>
As shown in FIG. 15, the present embodiment includes a file type determination step S0401 and a normal use application determination step S0402 in the process of the file-application relationship analysis step S04 of the third embodiment shown in FIG. 12 (see FIG. 5). In the meantime, a period narrowing step S0404 for narrowing down the file type-application correspondence table with access-permitted period information is added, and in the dialog screen display step S07, modification is made so that an access right period can be set on the screen to be displayed. -Remodeling to update the period information in the application correspondence table update step S11.

Next, a fifth embodiment of the present invention will be described in detail with reference to the drawings.
<Description of configuration>
In the present embodiment, as shown in FIG. 16, an access prohibition log 09 is added to the configuration of the third embodiment (see FIG. 9) to record the result input by the user through the file permission dialogue means 06.

The access prohibition log 09 is shown in FIG.
Date and time (T0901): Date and time when the log is added. Application (T0902): Application name notified from the file use permission determination unit 04 to the file permission dialogue unit 06.
File name (T0903): File name notified from the file use permission judging means 04 to the file permission dialogue means 06.

The file permission dialogue unit 06 registers user input information in the access prohibition log 09. The registration method adds one record, and stores the value of this record in the following manner.
Date / time: Record addition date / time Value of screen application name (U0601) of application-file permission dialogue means 06 S file name: Value of screen file name (U0602) of file permission dialogue means 06 Type (T0904): User prohibited (U0604) When “” is selected, “prohibited” is set. When the user selects permission (U0603) this time, “permit this time” is set. When the user selects permission (U0605) in the future, if the period (U0606) is set, the value of the period (U0606) is set, and if not set, “add” is set.

In the example of FIG. 17, the first record is WORDDPAD.2006 / 3/29 10:00:32. Sales with an application called EXE. Indicates that an attempt was made to use DOC but it was prohibited. The second record was recorded at WEMAIL. Sales with an application called EXE. Indicates that the DOC is accessed and set to be permanently accessible in the future.
As a result, what kind of prohibition operation the user has performed and what kind of access right setting has been changed remain in the record, making it more secure.

<Description of operation>
In this embodiment, as shown in FIG. 18, an access prohibition log adding step S12 is performed between the user access right setting step S08 and the user access right setting branching step S09 in the operation of the third embodiment (see FIG. 12). Add.

  In the access prohibition log adding step S12, the file access permission setting input by the user is left in the log (refer to <Description of Configuration> above for this method).

As described above, according to the information processing terminal device, the file outflow prevention method, and the file outflow prevention program of the present invention, the following effects can be obtained.
The first effect is that information leakage from software that the user does not know can be prevented. This is a file-application relationship analysis means, which defines an application that is safe to read for each file type, and based on this definition, the file usage permission judgment means permits access each time the application accesses the file. In order to determine whether or not to prohibit, the file can be accessed only from an authorized application. Therefore, it is possible to prevent unknown software such as a virus from transferring a file via the network without the user's knowledge.
The second effect is that the user does not have to make any special settings for this system, and can be operated correctly. This is because the file-application relationship determining means for automatically determining the read permission of the file from the relationship between the type of file possessed by the OS and the default application related thereto, and the data of the file to be accessed File type determination means for automatically determining the file type, application-file association learning means for learning a combination of a file type and an application that is safe to read from the usage history of the user's application, and monitoring the use of the application network By having an application analysis means that automatically determines the safety of the application in the configuration, if the user uses it normally without setting anything, the file type and reading are safe The combination can be defined. One of the drawbacks of the security countermeasure software is an error in setting, and it is an important feature that the end user does not need to set as in the present invention.
The third effect is that the user-friendliness is not impaired. This is because the user can give permission while confirming interactively.

  As mentioned above, although each Example of this invention was described, it is not limited to said each Example, A various deformation | transformation is possible in the range which does not deviate from the summary.

  INDUSTRIAL APPLICABILITY According to the present invention, it can be applied to a corporate personal computer or the like that can prevent a software such as a virus from transferring a confidential file in the personal computer to a computer unintended by the user using a network.

It is a block diagram which shows the structure of Example 1 of this invention. It is a block diagram which shows the structure of Example 1 of this invention. It is a figure which shows an example of the data of Example 1 of this invention. It is a figure which shows the processing flow of Example 1 of this invention. It is a figure which shows the processing flow of Example 1 of this invention. It is a block diagram which shows the structure of Example 2 of this invention. It is a figure which shows the example of a screen of Example 2 of this invention. It is a figure which shows the processing flow of Example 2 of this invention. It is a block diagram which shows the structure of Example 3 of this invention. It is a figure which shows the example of a screen of Example 3 of this invention. It is a figure which shows an example of the data of Example 3 of this invention. It is a figure which shows the processing flow of Example 3 of this invention. It is a figure which shows the example of a screen of Example 4 of this invention. It is a figure which shows an example of the data of Example 4 of this invention. It is a block diagram which shows the structure of Example 4 of this invention. It is a block diagram which shows the structure of Example 5 of this invention. It is a figure which shows an example of the data of Example 5 of this invention. It is a figure which shows the processing flow of Example 5 of this invention.

Explanation of symbols

01 application 02 operating system use hook means 03 operating system 04 file use permission judging means 05 file-application relation analyzing means 06 file permission dialogue means 07 file type-application correspondence table updating means 09 access prohibition log 0501 file-application relation judging means 0502 File type-application correspondence table T050201 File type T050202 Normal use application T050203 Period T0901 Date and time T0902 Application T0903 File name T0904 Type U0601 Application name U0602 This time permission button U0604 Prohibited button U0605 Future permission button U0600

Claims (19)

In an information processing terminal device having a communication function via a network,
An application that is software that provides a predetermined service to a user;
An operating system that is software that provides basic functions commonly used by the application software;
Operating system use hook means for detecting use of the operating system from the application;
A file application relation analyzing unit for determining an application normally used by the file with respect to the file detected by the operating system use hook unit;
Based on the determination result of the file application relationship analysis unit, a file usage permission determination unit that controls access detected by the operating system usage hook unit;
An information processing terminal device comprising: The file application relationship analysis means includes:
A file type application correspondence table describing the correspondence between the file type and the application normally used by the file;
File application relation determining means for determining whether or not the file is accessed by a normally used application based on the attribute information of the file detected by the operating system use hook means and the file type application correspondence table When,
The information processing terminal device according to claim 1, further comprising:   3. The information processing terminal device according to claim 2, wherein the file type application correspondence table includes a correspondence between a file name extension and an execution file name of an application normally used by the file.   The apparatus further comprises file permission dialogue means for allowing the user to interactively select whether to permit or prohibit the file access when there is a file access other than the normal use application. The information processing terminal device according to any one of 1 to 3.   When the user permits file access other than the normal use application using the file permission dialogue means, the file type application correspondence table is displayed to permit the access when there is similar access thereafter. 5. The information processing terminal device according to claim 4, further comprising a file type application correspondence table updating means for updating.   6. The file permission dialogue means allows the user to set an effective period for permitting predetermined file access, and the setting of the effective period is reflected in the file type application correspondence table. Information processing terminal device.   The information processing terminal device according to claim 4, further comprising an access prohibition log that records a result input by the user through the file permission dialog unit. Information processing provided with an application that is software that provides a predetermined service to a user, an operating system that is software that provides basic functions commonly used by the application software, and a communication function via a network A file leakage prevention method executed on a terminal device,
The information processing terminal device
When a predetermined application is used by the user,
An API calling step for calling a system call published by the operating system to the application when the application uses a function provided by the operating system;
An API call hook step that enters between the application and the operating system and intercepts a file system call in the call to the system call;
Information on the application trying to access the file and information on the file are extracted from the system call parameters regarding the file system intercepted in the API call hook step, and whether the file access is from an application normally used by the file File application relationship analysis step to determine whether or not
As a result of the file application relationship analysis step, a file use branching step for switching processing when there is permission to access the file and when there is no permission,
An API recall step for recalling the system call taken in the API call hook step to the operating system when it is determined that the file can be used in the file use branch step;
A file outflow prevention method comprising: The information processing terminal device
In the file application relationship analysis step,
A file type determination step for determining the type of the accessed file;
Whether or not the accessed file is a normally used application based on the file type determined in the file type determining step and a file type application correspondence table describing a correspondence relationship between the file and the normally used application A normal use application determination step for determining whether or not
A file use determination step that compares the normal use application determined in the normal use application determination step with the application that is actually trying to access and determines the availability,
The file outflow prevention method according to claim 8, wherein: The information processing terminal device
An interactive screen display step for displaying a screen for selecting whether the user interactively permits or prohibits the access;
A user access right setting step in which whether the access is permitted or prohibited by the user on the screen displayed in the interactive screen display step;
Based on the result of the user access right setting step, a user access right setting branching step for branching the operation;
The file outflow prevention method according to claim 8 or 9, further comprising: The information processing terminal device
An access permission file type determination step for determining a file type to which file access permission is given;
File type application correspondence table update that updates the file type application correspondence table based on the result of the access permission file type determination step and the application name input by the user on the screen displayed in the interactive screen display step Steps,
The file outflow prevention method according to claim 8, further comprising: The information processing terminal device
In the file application relationship analysis step, a period narrowing step for narrowing down the file type application correspondence table based on the period information for permitting access is further executed between the file type determination step and the normal use application determination step. The file outflow prevention method according to any one of claims 8 to 11, wherein the file is prevented from flowing out. The information processing terminal device
The step of adding an access prohibition log for leaving a file access permission setting input by the user in a log is further executed between the user access right setting step and the user access right setting branching step. The file outflow prevention method according to any one of items 1 to 12. Information processing provided with an application that is software that provides a predetermined service to a user, an operating system that is software that provides basic functions commonly used by the application software, and a communication function via a network A file leakage prevention program for causing a terminal device to execute a file leakage prevention method,
In the information processing terminal device,
When a predetermined application is used by the user,
API call processing for calling a system call that is published to the application by the operating system when the application uses a function provided by the operating system;
An API call hook process that intervenes between the application and the operating system and intercepts a file system call in the call to the system call;
Information on the application trying to access the file and information on the file are extracted from the system call parameters regarding the file system intercepted by the API call hook process, and whether the file access is an access from an application normally used by the file File application relationship analysis processing to determine whether
As a result of the file application relationship analysis process, a file usage branch process for switching the process depending on whether or not there is permission to access the file;
An API recall process for recalling a system call taken in the API call hook process to the operating system when it is determined that the file use branch process is available;
A file outflow prevention program characterized in that is executed. In the information processing terminal device,
In the file application relationship analysis process,
A file type determination process for determining the type of file that has been accessed;
Whether the accessed file is a normally used application based on the file type determined in the file type determining process and a file type application correspondence table describing a correspondence relationship between the file and the normally used application Normal use application determination processing to determine whether
A file availability determination process that compares the normally used application determined in the normal use application determination process with the application that is actually trying to access and determines the availability,
15. The file outflow prevention program according to claim 14, wherein: In the information processing terminal device,
An interactive screen display process for displaying a screen for the user to select whether to permit or prohibit the access interactively;
A user access right setting process in which whether the access is permitted or prohibited by the user on the screen displayed in the interactive screen display process;
Based on the result of the user access right setting process, a user access right setting branch process for branching the operation;
16. The file outflow prevention program according to claim 14 or 15, further comprising: In the information processing terminal device,
An access permission file type determination process for determining a file type to which file access permission is granted;
File type application correspondence table update for updating the file type application correspondence table based on the result of the access permission file type determination processing and the application name input by the user on the screen displayed in the interactive screen display processing Processing,
The file outflow prevention program according to any one of claims 14 to 16, further comprising: In the information processing terminal device,
In the file application relationship analysis process, a period narrowing process for narrowing down the file type application correspondence table based on the period information for permitting the access is further executed between the file type determination process and the normal use application determination process. The file outflow prevention program according to any one of claims 14 to 17, characterized in that: In the information processing terminal device,
17. The access prohibition log adding process for leaving the file access permission setting input by the user in a log is further executed between the user access right setting process and the user access right setting branching process. The file outflow prevention program according to any one of items 1 to 18.

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