WO2015170801A1 - Appareil et procédé pour empêcher une attaque par un tiers interposé (mitm) - Google Patents

Appareil et procédé pour empêcher une attaque par un tiers interposé (mitm) Download PDF

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Publication number
WO2015170801A1
WO2015170801A1 PCT/KR2014/007619 KR2014007619W WO2015170801A1 WO 2015170801 A1 WO2015170801 A1 WO 2015170801A1 KR 2014007619 W KR2014007619 W KR 2014007619W WO 2015170801 A1 WO2015170801 A1 WO 2015170801A1
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WO
WIPO (PCT)
Prior art keywords
screen
security
decryption
unit
input
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Application number
PCT/KR2014/007619
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English (en)
Korean (ko)
Inventor
맹영재
박응기
박현동
서정택
Original Assignee
한국전자통신연구원
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Publication of WO2015170801A1 publication Critical patent/WO2015170801A1/fr

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/50—Monitoring users, programs or devices to maintain the integrity of platforms, e.g. of processors, firmware or operating systems
    • G06F21/55—Detecting local intrusion or implementing counter-measures
    • G06F21/56—Computer malware detection or handling, e.g. anti-virus arrangements
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/30—Authentication, i.e. establishing the identity or authorisation of security principals

Definitions

  • the present invention relates to an apparatus and method for preventing a MITM attack, and more particularly, to an apparatus and method for effectively preventing a man in the middle (MITM) attack by extending a client in a server / client model to a screen level. .
  • MITM man in the middle
  • service providers use various methods of sharing secret information (eg, passwords, certificates, security cards, OTPs, TANs, etc.) with users, using cryptographic protocols, and installing security programs.
  • secret information eg, passwords, certificates, security cards, OTPs, TANs, etc.
  • the security element of online user authentication (hereinafter referred to as user authentication) can be divided into three parts.
  • the first part is secret information shared between the service provider and the user (password, certificate, security card, OTP, etc., hereinafter referred to as "shared secret")
  • the second part is the cryptographic protocol
  • the third part is the client It is a security program installed on.
  • Shared secrets are used as evidence for authenticating users, cryptographic protocols are used to ensure a secure channel between service providers and users, and security programs are used to counter security threats that may occur at the client.
  • the cryptographic protocol is safe from attackers if the cryptographic key is not exposed. However, since security programs are designed to provide security services for known malware, security against unknown malware cannot be expected.
  • Shared secrets are entered into the client through input devices such as keyboards and mice, and cryptographic keys of cryptographic protocols also exist within the client. Since it is assumed that the malware can acquire all the resources of the client, it is not easy to block all the paths of malicious code that can obtain such input values and encryption keys.
  • the current user authentication is made on the assumption that the client is secure, but in reality it is not considered secure because the assumption may not apply.
  • Korean Patent Registration No. 10-1230055 contents providing security for a portion where personal information and the like are displayed on the screen are described in Korean Patent Registration No. 10-1230055.
  • the content of Korean Patent No. 10-1230055 is a software level screen security.
  • the present invention has been proposed to solve the above-described problems, and provides an apparatus and method for preventing MITM attacks that can extend the client in the server / client model to the screen level to cope with MITM attacks occurring at the client level. Has its purpose.
  • MITM attack prevention device according to a preferred embodiment of the present invention to achieve the above object is a MITM attack prevention device that is included in the screen connected to the server through the client,
  • a key storage unit for storing a key shared with the server;
  • a decoder which decrypts the data input through the client based on the key and outputs the same on the screen;
  • a screen security display unit for performing screen security on or warning of the screen based on whether decryption is normal in the decryption unit;
  • An encryption unit for encrypting and outputting input data requiring security from a user based on the key; And outputting the results of the decryption unit and the encryption, respectively, when the decryption in the decryption unit is normal, and controlling the screen security display unit when the decryption in the decryption unit is abnormal.
  • a control unit for performing a corresponding display.
  • the key may be provided directly from the server or generated based on secret information.
  • the secret information may be any one of a password, a security card, a public certificate, OTP, TAN.
  • the secret information may be input by touching a virtual screen on the screen.
  • the secret information may be input through a keyboard and a mouse connected to an input terminal installed on the screen.
  • the secret information may be input through a camera installed on the screen.
  • the screen security display unit may include a light emitting device, and when the decryption of the decryption unit is normal, the screen security display unit may output green light indicating the screen security on.
  • the screen security display unit may include a light emitting device, and the screen security display unit may warn by outputting red light when the decryption in the decryption unit is abnormal.
  • the screen security pattern storage unit for storing the screen security pattern displayed on the screen when the screen security on state may further include.
  • the controller may warn through the screen security display unit if the screen security pattern is included in the data from the client.
  • MITM attack prevention method according to a preferred embodiment of the present invention, MITM attack prevention method in the MITM attack prevention device included in the screen connected to the server through the client,
  • the method may further include displaying a previously stored screen security pattern on the screen when the screen security is on.
  • the screen security pattern is included in the data from the client; the step of warning it may be further included.
  • FIG. 1 illustrates a server / screen model to which the present invention is applied.
  • FIG. 2 is a block diagram of a MITM attack prevention apparatus according to an embodiment of the present invention.
  • FIG. 3 is a flowchart illustrating an example of a method for preventing MITM attack according to an embodiment of the present invention.
  • FIG. 8 is a flowchart for explaining a process of transmitting an input from a keyboard received from a screen shown in FIG. 1 to a server.
  • FIG. 9 is a flowchart illustrating another example of a method for preventing MITM attack according to an embodiment of the present invention.
  • FIG. 10 is a diagram employed in the description of FIG. 9.
  • the present invention proposes a server / screen model instead of a server / client model to securely authenticate a user online even under the assumption that malicious code may be installed in the client.
  • FIG. 1 illustrates a server / screen model to which the present invention is applied.
  • the client 20 in the server 10 / client 20 model is screened (output terminal; for example). , Monitor) to 30 levels is required.
  • MITM man in the middle
  • the server 10 and the client 20 which are both terminals, perform encryption communication, so that the security of the network and the client 20 cannot be trusted, so that the server 10 and the screen 30 are not secured. It is configured to perform cryptographic communication.
  • the client 20 is only responsible for transferring encrypted input / output data between the server 10 and the screen of the screen 30. However, when the client 20 transmits the encrypted screen data to the screen of the screen 30, the client 20 should transmit a specific signal to inform the user of the screen security operation to the screen terminal.
  • extending the cipher range down to the screen 30 level is also related to the human-computer interaction (HCI).
  • HCI human-computer interaction
  • the client 20 is a tool for transferring input and output data of the server 10 and the user.
  • the client 20 delivers information to the user through the monitor output and the value entered by the user via the keyboard / mouse to the server 10.
  • the client 20 is infected with malicious code, both output and input become unreliable. That is, the client 20 located between the server 10 and the user may be used in a MITM attack to deceive both the server 10 and the user by modulating the HCI data.
  • FIG. 2 is a block diagram of the MITM attack prevention device according to an embodiment of the present invention, it can be understood as an internal block diagram of the screen 30 shown in FIG.
  • the screen 30 includes a receiver 41, an encryption key generator 42, an encryption key storage unit 43, a decryption unit 44, a screen 45, a screen security display unit 46, an encryption unit 47, Transmitter 48, screen security pattern storage unit 49, and the control unit 50.
  • the reception unit 41 receives screen data (i.e., encrypted data) requiring security provided from the server 10 (e.g., an Internet account transfer screen, screen data for confirming a transaction amount history, etc.).
  • screen data i.e., encrypted data
  • the server 10 e.g., an Internet account transfer screen, screen data for confirming a transaction amount history, etc.
  • the receiver 41 may exchange or share an encryption key from the server 10. This is because the server 10 and the screen 30 use a key exchange / sharing protocol to have an encryption key. Meanwhile, the receiver 41 may receive secret information (ie, a source for generating an encryption key) from the outside. Of course, the receiver 41 may also receive MITM attack data (ie, encrypted data created to deceive the user) at the client 20.
  • secret information ie, a source for generating an encryption key
  • MITM attack data ie, encrypted data created to deceive the user
  • the receiver 41 receives input data requiring security from the user.
  • input data requiring security may be input through a keyboard and / or a mouse.
  • the encryption key generation unit 42 generates an encryption key based on the secret information received through the reception unit 41.
  • the secret information may be a password, a security card, a public certificate, a one time password (OTP), a transaction authentication number (TAN), and the like. Because passwords, security cards, and public certificates can be exposed during distribution, it is safe to use secret information that is difficult to replicate, such as OTP. It is assumed that the encryption key generation unit 42 incorporates an encryption algorithm.
  • the encryption key storage unit 43 stores the encryption key generated by the encryption key generation unit 42.
  • the encryption key storage unit 43 may store the encryption key from the server 10. As a result, it can be seen that the encryption key in the encryption key storage unit 43 is shared with the server 10.
  • the encryption key may be an example of a key described in the claims of the present invention.
  • the decryption unit 44 decrypts the screen data requiring security from the server 10 received by the reception unit 41. Meanwhile, the decryption unit 44 will decrypt the MITM attack data received from the client 20 received by the reception unit 41. It is assumed that the decoding unit 44 has a built-in decoding algorithm.
  • the decryption unit 44 decrypts the encryption key stored in the encryption key storage unit 43 (that is, the encryption key shared with the server 10) when decrypting the screen data requiring security from the server 10. Since decryption is performed based on the (), normal decryption will be performed. However, when the decryption unit 44 decrypts the MITM attack data from the client 20, since the encryption key stored in the encryption key storage unit 43 and the encryption key of the MITM attack data are different from each other, proper decryption is performed. Will not lose.
  • the screen 45 displays the screen data decoded by the decoder 44.
  • the screen security display unit 46 displays whether or not the screen security.
  • the screen security display unit 46 displays a visual display through a display device such as a light emitting device (LED) to inform the user of the on / off state of the screen security.
  • a display device such as a light emitting device (LED)
  • the light emitting device when the screen security is OFF, the light emitting device does not output any light, and when the screen security is ON, the light emitting device may output green light. At least one light emitting element may be used.
  • the screen security display unit 46 may be installed on the screen 30 separately from the screen 45.
  • the screen data is abnormal because the malicious attacker does not know the encryption key stored in the screen 30. (I.e., MITM attack data).
  • MITM attack data the encryption key stored in the screen 30.
  • the decryption unit 44 decrypts the MITM attack data (encrypted data) in the client 20, proper decryption is not performed, and thus the screen security display unit 46 may display such a case. For example, red light may be output from the light emitting device to indicate that decoding is not performed properly.
  • the screen security display unit 46 may display the screen security pattern of the screen security pattern storage unit 49 on the screen 45 in the screen security state.
  • the screen security pattern may not be displayed as a light emitting device, but may have a form in which a green strip is formed along the edge of the screen 45.
  • the screen security display unit 46 is an abnormal state (that is, it can be seen as a case where malicious code is detected). I can display it.
  • the encryption unit 47 encrypts input data requiring security received by the reception unit 41. At this time, the encryption unit 47 encrypts the encryption key based on the encryption key stored in the encryption key storage unit 43.
  • the transmitter 48 sends the input data encrypted by the encryption unit 47 to the server 10.
  • the screen security pattern storage unit 49 stores the screen security pattern to be output to the screen 45 in the screen security state.
  • the controller 50 is responsible for controlling the internal configuration of the screen 30. That is, when the control unit 50 receives the encryption key through the receiver 41, the controller 50 stores the encryption key in the encryption key storage unit 43. When the controller 50 receives the secret information through the receiver 41, the controller 50 sends the secret information to the encryption key generator 42. When the control unit 50 receives screen data requiring security through the receiving unit 41, the control unit 50 transmits the screen data to the decryption unit 44. When the control unit 50 receives input data requiring security through the receiving unit 41, the control unit 50 transmits the received input data to the encryption unit 47. The controller 50 determines whether or not the screen security, and sends the result to the screen security display 46, and, if a malicious code is detected, sends the fact to the screen security display 46.
  • FIG. 3 is a flowchart illustrating an example of a method for preventing MITM attack according to an embodiment of the present invention
  • FIGS. 4 to 7 are diagrams employed in the description of FIG. 3.
  • the screen 30 may be provided with an encryption key directly from the server 10, but in the following description, it is assumed that the encryption key is generated by receiving secret information.
  • the receiver 41 of the screen 30 receives the input secret information (S10).
  • 4 to 6 illustrate an example of inputting secret information on a screen. 4 illustrates a case in which the screen 30 has a touch screen function. In FIG. 4, a user may touch the virtual screen 51 on the screen 45 to input secret information. 5 illustrates an example in which the screen 30 has an input terminal such as USB or PS / 2. In FIG. 5, secret information may be input by connecting an input device 52 such as a keyboard and a mouse to an input terminal. 6 shows a case where the camera 53 is located on the screen 30. In FIG. 6, the camera 53 may directly capture and input secret information, or may input secret information through OCR reading. On the other hand, the camera 53 can photograph a multi-dimensional code (for example, a QR code), obtain secret information from the photographing information, and input it.
  • a multi-dimensional code for example, a QR code
  • the secret information is sent to the encryption key generation unit 42.
  • the encryption key generation unit 42 generates an encryption key using the received secret information, and stores the generated encryption key in the encryption key storage unit 43 (S12).
  • the server 10 sends the screen data requiring security to the screen 30 via the network. Accordingly, the receiver 41 of the screen 30 receives screen data requiring security (S14).
  • the controller 50 of the screen 30 decrypts the screen data requiring security (for example, an internet account transfer screen, screen data for confirming a transaction amount history, etc .; encrypted data).
  • Send to The decryption unit 44 decrypts screen data requiring security.
  • the server 10 sends the screen data encrypted using the shared encryption key
  • the malicious attacker will try to trick the user elaborately by using a technique such as farming.
  • the screen data is abnormal because the malicious attacker does not know the encryption key stored in the screen 30. (I.e., MITM attack data).
  • MITM attack data the encryption key stored in the screen 30.
  • the decryption unit 44 decrypts the MITM attack data (encrypted data) in the client 20, proper decryption is not performed.
  • the decoder 44 when the decoding is not normally performed (“No” in S16), the decoder 44 notifies the controller 50 of this. Accordingly, the controller 50 issues a warning of outputting red light through the screen security display unit 46 (S18). Of course, the controller 50 may turn the entire screen 45 black with a warning through the screen security display unit 46, so that nothing can be seen.
  • the decoder 44 notifies the controller 50 of this. Accordingly, the controller 50 determines that the screen security is ON and displays the screen security ON through the screen security display 46 (S20). For example, initially, as shown in FIG. 7A, the light emitting device 54 is turned off and the screen security is turned off. When the screen security is turned on, the light emitting device ( 54) lights up to output green light.
  • the decoder 44 then displays the decoded screen data on the screen 45 (S22).
  • the control unit 50 of the screen 30 is in a screen security off state. To close the screen security. That is, when the screen requiring security ends, it returns to the normal screen.
  • FIG. 8 is a flowchart for explaining a process of transmitting an input from a keyboard received from a screen shown in FIG. 1 to a server.
  • screen 30 is connected to a keyboard and mouse.
  • the receiver 41 receives the security input data (S30).
  • the controller 50 applies the input data requiring security to the encryption unit 47.
  • the encryption unit 47 encrypts the input data requiring security based on the encryption key stored in the encryption key storage unit 43 (S32).
  • the encrypted input data is transmitted to the server 10 through the transmitter 48 (S34).
  • S30 to S34 may be regarded as being performed after S22 in FIG. 3 described above. That is, when the screen data requiring security is decrypted and displayed on the screen 45, the user views the screen data and inputs corresponding input data (that is, input data requiring security). The input data is encrypted and sent to the server 10.
  • the input data is encrypted and transmitted to the server 10 only when the screen security is in operation. Since the screen security is ON while the operations S30 to S34 are being performed, the light emitting device 54 will output green light as shown in FIG. 7B.
  • FIG. 9 is a flowchart for explaining another example of the method for preventing MITM attack according to the embodiment of the present invention
  • FIG. 10 is a diagram employed in the description of FIG. 9.
  • the screen 30 receives predetermined screen data through the client 20 (S40).
  • controller 50 of the screen 30 determines whether the received screen data includes the screen security pattern.
  • the controller 50 determines that the currently input screen data is MITM attack data (eg, malicious code) sent by a malicious attacker (S44).
  • MITM attack data eg, malicious code
  • the malicious code detection is displayed on the screen 45 (S46).
  • the screen security is changed from the screen security off state to the normal screen security on state as shown in FIG. 10a
  • the screen 30 allows a red band to be formed along the edge of the screen 45.
  • characters such as "malware detected” and "do not input important information” may be displayed together.
  • the screen security pattern can be generated and displayed only on the screen 30.
  • a malicious attacker makes a screen security pattern through the client 20 and inputs the screen security pattern together with the screen data
  • the screen 30 from the client 20 Since it is known that a specific signal (ie, screen security pattern) is included in the screen data of, it may be determined that MITM attack data is input.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Theoretical Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • General Engineering & Computer Science (AREA)
  • Software Systems (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Virology (AREA)
  • User Interface Of Digital Computer (AREA)

Abstract

La présente invention concerne un appareil et un procédé pour empêcher une attaque par un tiers interposé (MITM). L'appareil de la présente invention est un appareil pour empêcher une attaque MITM inclus dans un écran connecté par l'intermédiaire d'un client à un serveur, l'appareil comprenant : une unité de stockage de clé pour stocker une clé partagée avec le serveur ; une unité de décodage pour décoder des données entrées par l'intermédiaire du client sur la base de la clé et délivrer ces dernières sur l'écran ; une unité d'affichage de sécurité d'écran pour activer une sécurité d'écran ou donner un avertissement sur l'écran sur la base du point de savoir si le décodage est ou non normal au niveau de l'unité de décodage ; une unité de chiffrement pour chiffrer des données d'entrée, pour lesquelles la sécurité issue d'un utilisateur est requise, sur la base de la clé et délivrer ces dernières ; et une unité de commande pour activer une sécurité d'écran pour permettre à chaque résultat de décodage et de chiffrement d'être délivré lorsque le décodage est normal au niveau de l'unité de décodage, et pour amener l'unité d'affichage de sécurité d'écran à afficher ce qui correspond à l'anomalie lorsque le décodage est anormal au niveau de l'unité de décodage.
PCT/KR2014/007619 2014-05-09 2014-08-18 Appareil et procédé pour empêcher une attaque par un tiers interposé (mitm) WO2015170801A1 (fr)

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KR1020140055316A KR101634785B1 (ko) 2014-05-09 2014-05-09 Ｍｉｔｍ 공격 방지 장치 및 방법
KR10-2014-0055316 2014-05-09

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Citations (3)

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KR20000025373A (ko) * 1998-10-10 2000-05-06 구자홍 데이터 암호화 방법
JP2009124311A (ja) * 2007-11-13 2009-06-04 Kddi Corp 相互認証システム、相互認証方法およびプログラム
KR20120093594A (ko) * 2011-02-15 2012-08-23 동서대학교산학협력단 공인인증서와 키수열발생기로 생성되는 ｏｐｔ를 이용한 트렌젝션보호 시스템 및 방법

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JP5102659B2 (ja) * 2008-03-13 2012-12-19 エヌ・ティ・ティ・コミュニケーションズ株式会社 悪性Ｗｅｂサイト判定装置、悪性Ｗｅｂサイト判定システム、それらの方法、プログラム

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KR20000025373A (ko) * 1998-10-10 2000-05-06 구자홍 데이터 암호화 방법
JP2009124311A (ja) * 2007-11-13 2009-06-04 Kddi Corp 相互認証システム、相互認証方法およびプログラム
KR20120093594A (ko) * 2011-02-15 2012-08-23 동서대학교산학협력단 공인인증서와 키수열발생기로 생성되는 ｏｐｔ를 이용한 트렌젝션보호 시스템 및 방법

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KR101634785B1 (ko) 2016-06-29

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