METHOD AND COMPUTER SYSTEM FOR CLEANING ELECTRONIC DOCUMENTS OF POSSIBLE MALFUNCTION

Description

[0001] The invention relates to a computer-implemented method and a computer system according to the preambles of the independent patent claims.

[0002] Malware that enters a local computer or network through the receipt of files from unsafe sources poses a major problem when using computers. Computer security solutions such as antivirus programs and software- or hardware-based firewalls are known to defend against such malware. However, it is repeatedly discovered that these computer security solutions fail to detect new malware or new attack variants, leaving computer users virtually defenseless against such attacks.

[0003] Generic computer systems are known, for example, from US 2018 / 262470 A1, US 2003 / 229810 A1 and US 2016 / 269422 A1.

[0004] Malware often enters a user's computer via email attachments or files downloaded from the internet. It is often nearly impossible for a user to determine whether a file contains malware or not. This is particularly problematic for computer systems that receive large amounts of data, including personal data or data that requires protection for other reasons. For example, healthcare facilities communicate with a large number of patients who transmit sensitive data via email. However, the source of the received electronic documents is often unknown and therefore potentially unsafe.

[0005] The object of the invention is to create a method or computer system that enables the secure and user-friendly cleaning of potential malware from electronic documents. In particular, this means that electronic documents can be freed from malware, whereby the malware itself may be unknown at the time of receipt and processing of the document content. In addition, this may mean that the cleaning of electronic documents takes place without additional, complex steps on the part of the user.

[0006] The object of the invention is achieved in particular by the features of the independent patent claims.

[0007] The invention particularly relates to a method and / or a computer-implemented method for cleaning electronic documents from possible malware, comprising the following steps: Receiving an electronic original document on a control computer; transmitting the electronic original document to a display computer; transmitting the document content of the original document via a display signal from the display computer to the control computer; creating an electronic document copy from the display signal by the control computer.

[0008] It may be advantageous if the original electronic document is first converted into an intermediate format before the display signal is generated, wherein the original document is in particular an electronic file of a word processing program, a graphics processing program or an e-mail program such as an electronic file in one of the following file formats: .doc, docx, pdf, xls, xlsx, ppt, pptx, e-mail or similar, and / or wherein the intermediate format is an image file such as a bitmap file, a pdf file or another container file, possibly containing several document pages.

[0009] Where appropriate, it is intended that the original document, particularly in intermediate format, is opened on the display computer.

[0010] Where appropriate, it is provided that the display signal is in particular the monitor signal of the display computer.

[0011] Where appropriate, the display signal may be recorded and the document content may be stored and / or displayed in a separate electronic file as a cleaned-up electronic document copy.

[0012] Where appropriate, the electronic document copy or the original document in the intermediate format is processed by text recognition software and the recognized text is stored in the document copy.

[0013] Where appropriate, the original electronic document may be received on the control computer from an insecure source, in particular from the Internet and / or from outside the local network.

[0014] Where appropriate, the original electronic document is provided for to be sent from a user computer to the control computer.

[0015] Where appropriate, the original electronic document may be transferred to a display computer via a serial data interface.

[0016] Where appropriate, the transmission of the document content of the original document from the display computer to the control computer is carried out via an HDMI signal or via a fiber optic signal.

[0017] Where appropriate, it is provided that when the document content of the original document is transferred from the display computer to the control computer, the entire document content of the original document is transferred.

[0018] If necessary, the display computer is provided to transmit only a display signal to the control computer or to the grabber.

[0019] Where appropriate, further information such as metadata, a page number, the original file name and / or a QR code may be added to the electronic document copy, with this information being attached in particular to the display signal.

[0020] In particular, the invention relates to a computer system for cleaning electronic documents from possible malware, comprising a control computer and a display computer, wherein the control computer receives an original electronic document and transmits it to the display computer, wherein the display computer transmits the document content of the original document received from the control computer back to the control computer via a display signal, and wherein the control computer creates an electronic document copy from the display signal.

[0021] The computer system is preferably configured or suitable for carrying out the method according to the invention.

[0022] Where appropriate, a serial data interface is provided via which the control computer transmits the original electronic document to the display computer.

[0023] Where appropriate, an HDMI interface or a fiber optic signal interface is provided through which the display computer transmits the document content back to the control computer.

[0024] A fundamental problem to be solved in the area of ​​the present invention is that a user must generally open the electronic document to be cleaned in order to check its content. In practice, a suspicious electronic document often cannot simply be ignored or deleted, as the content may be important to the recipient. The proposed system provides an isolated system, in particular a display computer. This display computer includes the ability to open the electronic document to be cleaned and to capture and / or output the document content. However, the display computer is preferably part of an isolated system that is separated from the internal system, i.e., in particular, from the local network or the user's computer, in such a way that any malware cannot affect the rest of the system, in particular the user's internal system.

[0025] Several areas of application can be cited as examples for the method according to the invention and for the computer system according to the invention: For example, the document content of electronic documents can be securely processed and downloaded from the Internet, for example. This applies to medical findings that are provided by a patient via email or via download from the Internet. Alternatively, such files can also be made available via a mobile storage medium, such as a USB stick. These files or electronic documents can be freed of any malware using the computer system according to the invention and the method according to the invention. A generic application concerns the cleaning of electronic documents that are received, for example, via email or another communication medium.In addition, documents downloaded from websites, although they must not be opened beforehand, can also be displayed securely.

[0026] If necessary, the electronic document to be cleaned can be transferred to the isolated system via a serial interface and paged through. This interface can preferably only transfer data in one direction.

[0027] In some cases, the HDMI interface does not transmit binary files or program files but only the image to be displayed of a document page displayed by the isolated system.

[0028] If necessary, the internal system can receive information about how many pages are contained in the document and, if applicable, that the display of the requested page(s) has been completed via a QR code additionally displayed on the screen of the isolated system.

[0029] Preferably, the internal system captures the screen signal from the display PC via a grabber, saves it as an image, and requests the next page or section – until the entire document or document content has been transferred. It then generates a clean copy of the document from all images, and in particular, a secure PDF document.

[0030] Should the isolated system be compromised by malware, the impact is limited to the isolated system. Since there is no vulnerable data connection to the internal system, unsafe files cannot re-enter the internal system.

[0031] If the display computer is infected with malware, it can be easily reset. Simply replacing the system memory, such as a micro SD card, can restore the system to full functionality.

[0032] In some cases, the display computer may use a read-only file system, preventing malware from infiltrating the operating system. A simple reboot can reset the system to restore full functionality.

[0033] Preferably, the computer system operates fully automatically, eliminating the need for individual file classification (by users, etc.). The hardware required for the computer system is preferably composed of simple, commercially available components and is therefore inexpensive.

[0034] When transferring the document content of the original document via a display signal from the display computer to the control computer, the display signal is supplemented, if necessary, by a control signal integrated into the display signal, e.g. in the form of QR codes from the display computer to the control computer.

[0035] The intermediate format is preferably an image file. Alternatively, the intermediate format can be a bitmap file, a PDF file, or another container file containing multiple document pages.

[0036] The invention will be further described below with reference to the figures. Fig. 1 shows a schematic representation of the basic components of the computer system or method. Fig. 2 shows a possible design of a computer system. Fig. 3 shows a schematic representation of another embodiment of a possible computer system.

[0037] Unless otherwise stated, the reference numerals correspond to the following components: control computer 1, display computer 2, display signal 3, insecure source 4, local network 5, serial data interface 6, HDMI signal 7, HDMI interface 8, isolated system 9, internal system 10, network interface 11, display device 12, grabber 13, splitter 14, user computer 15, IMAP server 16, SMTP server 17.

[0038] Fig. 1 shows a schematic representation of the basic components of a possible embodiment of a computer system, in particular for carrying out a described method. An electronic document such as an electronic file of a word processing program, a graphics processing program, an e-mail program, in particular an unopened attachment of an e-mail program, or the like is sent from an insecure source 4 to the internal system 10. The electronic document can be a document from any insecure source. For example, a document downloaded from a website or a document received via a mobile data storage device. The internal system 10 is, for example, a local network 5 to which a user computer 15 is coupled, wherein the user computer 15 is either integrated directly into the local network 5 or by means of a router orFirewall can be connected to it, or communicates indirectly with the internal system, for example by sending emails, transferring documents via a mailbox, or transferring documents via a server service on the Internet. In particular, according to the present embodiment, the internal system 10 contains a control computer 1. The document or file is transferred to the control computer 1 via a network interface 11, for example by email or via another digital means. Before the electronic document to be cleaned is opened in the internal system 10, it is transmitted from the control computer 1 to a display computer 2. The transmission of the electronic document to be cleaned to the display computer 2 can take place via a suitable data connection or data interface, in particular via a serial data interface 6. The display computer 2 is part of an isolated system 9.This isolated system 9 is preferably isolated from the internal system 10 to such an extent that any malware from the display computer 2 cannot reach the internal system 10, the control computer 1 and especially not the user computer 15.

[0039] The display computer 2 generates a display signal 3 and transmits it back to the control computer 1. The display signal 3 is generated in particular by the electronic document to be cleaned being opened on the display computer 2. Subsequently, the signal which is preferably usually sent to a

[0040] The signal is sent from a display device 12, such as a monitor, back to the control computer 1. However, this display signal 3 only contains information about the displayed image. Malware cannot generally be transmitted via this signal. In some cases, the display signal 3 is an HDMI signal 7, which is transmitted via an HDMI interface 8. From this display signal 3, the control computer 1 can then subsequently create an electronic document copy. This document copy preferably only copies the document content, but not any malware or metadata.

[0041] If necessary, the original electronic document is first converted into an intermediate format before generating the display signal 3. The intermediate format can be, for example, an image file such as a bitmap file or a PDF file. The original document can essentially be any type of document file that the display computer 2 can open.

[0042] Preferably, the document to be cleaned is transmitted from the control computer 1 to the display computer 2 via an interface or a data line that can only send data in one direction. For example, this can be implemented via a serial interface 6.

[0043] If necessary, additional information can be added to the display signal 3 in all embodiments. For example, further information such as a page number or other information can be added to the document content. This can, for example, be noted on the electronic copy of the document. For example, a QR code can appear on the document copy, providing information about metadata such as the page number, original file name, or other information.

[0044] Fig. 2 shows a possible embodiment of a computer system. The system comprises a control computer 1 connected to a display computer 2. In particular, this connection is established via a serial data interface 6. In the present case, a USB-RS232 adapter is connected to each of the USB ports of the control computer 1 and the display computer 2, with the two serial interfaces being coupled to each other via a null-modem connection. These two cables are coupled to each other via a null-modem connection to establish the connection.

[0045] A user computer 15 is connected to an unsafe source 4 via a network interface 11 to receive electronic documents to be cleaned. To clean these electronic documents, the user computer 15 can send the electronic file or the electronic document to be cleaned—preferably unopened—to the control computer 1.

[0046] This can be done, for example, via a REST interface. The control computer 1 thus receives electronic documents from an insecure source 4.

[0047] In the present embodiment, the computer system comprises a display device 12, which is designed in particular as a monitor. This display device 12 is suitable and / or configured to display the display signal 3 of the display computer 2 and, if applicable, the control computer 1. If appropriate, two display devices 12 can also be provided for this purpose, although this embodiment is not shown. The display computer 2 is connected to the control computer 1 to transmit the display signal 3 to the latter. In particular, this occurs via the HDMI interface 8 or via the HDMI signal 7. In the present embodiment, a so-called grabber 13 is provided for this purpose, i.e., a device that digitizes or records the display signal 3.This grabber 13 is connected to the control computer 1 so that it can record the display signal 3 or process the recorded signal to create a digital document copy.

[0048] In the present case, a splitter 14 is provided between the grabber 13 and the display computer 2, which transmits the display signal 3 to the grabber 13 on the one hand, but also to the display device 12 on the other. If necessary, the connection between the display computer 2 and the display device 12 can also be omitted.

[0049] As an alternative to the HDMI signal 7, the transmission of the display signal 3 can be carried out in all embodiments via a fiber optic signal.

[0050] If an electronic document to be cleaned is now transmitted from the unsafe source 4 to the control computer 1, this file is forwarded, preferably unopened, to the display computer 2. On the display computer 2, the electronic document to be cleaned is opened and displayed, or a display signal 3 is generated. The display signal 3 is sent back to the control computer 1, with a grabber 13 preferably provided between the control computer 1 and the display computer 2. The display signal 3 is stored and / or displayed. This creates a cleaned, digital document copy.

[0051] If necessary, additional information is added to the document copy on the display computer 2 or on the control computer 1, such as the page number or a QR code.

[0052] As noted, in the computer system, the electronic document to be cleaned, for example, a PDF file, a word processing file, or another file, is sent or transmitted by the user, in particular from the user computer 15, to the control computer 1. This transmission can be carried out, for example, via a REST interface.

[0053] If necessary, the file is converted on the display computer 2 into an intermediate format, for example, a PDF file. Furthermore, the display computer 2 can browse through the electronic document and play it back to the control computer 1 section by section, in particular page by page, as a display signal 3. The control computer 1 can then record these sections or pages as an image and convert them into a readable file format, such as a PDF file.

[0054] If necessary, the digital document copy is analyzed by text recognition software so that the text in the image file is recognized and can be easily reused by the user.

[0055] The digital document copy, in particular with further information, can then be sent back to the user's computer 15, in particular in response to the REST request.

[0056] Preferably, the control computer 1 has no connection to the Internet and is preferably not used interactively. Rather, the electronic document to be cleaned is provided on a computer located in the same sensitive network, if necessary, and transmitted directly to the control computer 1 without opening it.

[0057] The display computer 2 is also preferably not integrated into the local network 5, but is only connected to the control computer 1 via the necessary interfaces for transmission and generation of the display signal 3. If the display computer 2 is infected with malware, it can be easily reset.

[0058] Control computer 1 may be equipped with an HDMI simulator dongle to ensure it always produces an image that can be displayed over the internal network using VNC. Display computer 2 is simulated as having a monitor connected, as grabber 13 identifies itself as a monitor. Troubleshooting in this case would require the captured images. If this isn't sufficient, an external monitor can be connected via an HDMI splitter.

[0059] Fig. 3shows a schematic representation of a computer system. The computer system comprises a control computer 1 and a display computer 2. The electronic document to be cleaned is transmitted, in particular, via email, for example, via an IMAP server 16, to the control computer 1. The control computer 1 recognizes the file(s), downloads them if necessary, or extracts the attachments, for example, files with the extensions pdf, doc, docx, xIs, xlsx, ppt, pptx, etc.

[0060] The electronic documents to be cleaned are transmitted, preferably individually, to the display computer 2. This occurs, for example, via a serial data interface 6. The display computer 2 preferably converts the documents to be cleaned into an intermediate format, opens this format, and browses through the files section by section or page by page. In the process, a display signal 3 is generated, which is transmitted back to the control computer 1. In particular, this is implemented via the screen output of the display computer 2 via a grabber 13. Furthermore, as in the other embodiments, the image generated thereby can be analyzed by text recognition software in order to capture the text. The data, in particular image data, text data, and other information, can then be combined to form a displayable document. This document can, for example, be a PDF file.The assembly takes place, if necessary, on control computer 1. This file can then be sent back to the user as an email. For example, control computer 1 is connected to an SMTP server 17 for this purpose.

[0061] Preferably, the control computer 1 is connected to the Internet, but this connection is limited to communication with the email server(s). The display computer 2 is preferably not part of the local network 5.

Claims

1. A computer-implemented method for clearing possible malware from electronic documents, comprising the following steps: - receiving an electronic original document on a control computer (1); - transmitting the electronic original document to a display computer (2); - transmitting the document content of the original document via a display signal (3) from the display computer (2) to the control computer (1); - the control computer (1) creating an electronic document copy from the display signal (3).

2. The method according to claim 1, characterized in that the original electronic document is first converted into an intermediate format before the display signal (3) is generated, - wherein the original document is in particular an electronic file of a word processing programme, a graphics processing programme or an e-mail programme, such as an electronic file according to one of the following file formats: .doc, docx, pdf, xls, xlsx, ppt, pptx, e-mail or similar, - and wherein the intermediate format is an image file and / or a bitmap file, a pdf file or another container file containing several document pages.

3. The method according to claim 1 or 2, characterized - in that the original document, in particular in the intermediate format, is opened on the display computer (2), - in that the display signal (3) is in particular the monitor signal of the display computer (2), - in that the display signal (3) is recorded and the document content is stored and / or displayed in a separate electronic file as a cleared, electronic document copy.

4. The method according to one of claims 1 to 3, characterized in that the electronic document copy or the original document in intermediate format is processed by a text recognition software and the recognized text is saved in the document copy.

5. The method according to one of claims 1 to 4, characterized - in that the electronic original document is received on the control computer (1) from an insecure source (4), in particular from the Internet and / or from outside the local network (5), - in particular in that the electronic original document is sent from a user computer (15) to the control computer (1).

6. The method according to one of claims 1 to 5, characterized in that the electronic original document is transmitted to a display computer (2) via a serial data interface (6).

7. The method according to one of claims 1 to 6, characterized in that the document content of the original document is transmitted from the display computer (2) to the control computer (1) via an HDMI signal (7) or via an optical fibre signal.

8. The method according to one of claims 1 to 7, characterized in that when the document content of the original document is transmitted from the display computer (2) to the control computer (1), the entire document content of the original document is transmitted.

9. The method according to one of claims 1 to 8, characterized in that the display computer (2) exclusively transmits a display signal (3) to the control computer (1) or to the grabber (13).

10. The method according to one of claims 1 to 9, characterized - in that further information, such as metadata, a page number, the original file name and / or a QR code, is added to the electronic document copy, - wherein this information is added in particular to the display signal (3).

11. A computer system for clearing possible malware from electronic documents, comprising a control computer (1) and a display computer (2), - wherein the control computer (1) receives an original electronic document and transmits it to the display computer (2), - wherein the display computer (2) transmits the document content of the original document received from the control computer (1) back to the control computer (1) via a display signal (3), - and wherein the control computer (1) creates an electronic document copy from the display signal (3).

12. The computer system according to claim 11, characterized in that a serial data interface (6) is provided, via which the control computer (1) transmits the electronic original document to the display computer (2).

13. The computer system according to claim 11 or 12, characterized in that an HDMI interface (8) or an optical fibre signal interface is provided, via which the display computer (2) transmits the document content back to the control computer (1).