ATM Security with Firewalls

$706HFXULW\ZLWK)LUHZDOOV  



&VDED6LPRQ      $WWLOD7|U|N +LJK6SHHG1HWZRUNV/DERUDWRU\'HSDUWPHQWRI7HOHFRPPXQLFDWLRQVDQG7HOHPDWLFV 7HFKQLFDO8QLYHUVLW\RI%XGDSHVW ^VLPRQWRURN`#WWWDWPWWWEPHKX   $EVWUDFW

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

,QWURGXFWLRQ 

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

 $Q 2YHUYLHZ RI WKH $70 6HFXULW\ 3URSRVDOV 

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¶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

2XU3URSRVDO 

2XU SURSRVDO LV EDVHG RQ WUDQVPLWWLQJ WKH VHFXULW\ VHUYLFH UHODWHG LQIRUPDWLRQV HJ NH\V DXWKHQWLFDWLRQ HWF EHWZHHQWZRILUHZDOOVLQEDQGDVSUHVHQWHGLQ)LJXUH  7KLV PHWKRG ZDV XVHG LQ >@ DV ZHOO 7KH ILUVW H[FKDQJH RI WKHVH LQIRUPDWLRQV DUH GRQH ULJKW DIWHU WKH HVWDEOLVKPHQW RI WKH FRQQHFWLRQ EHWZHHQ  WKH WZR ILUHZDOOV DQG EHIRUH WKH UHFHLYLQJ HQG UHFHLYHV WKH 6(783 PHVVDJH 7KLV PHWKRG PDNHV DOVR SRVVLEOH WR FKRRVH EHWZHHQ WKH WZR RU WKUHHZD\ NH\ H[FKDQJH SURWRFROV>@  8VHU$

)LUHZD OO$

)LUH ZDOO%

8VH U%

6(783 6(783

&211(&7

.H \H[ FKD QJH

6(783

&211(&7

>&211(&7@

&211(&7

3URWH FWHGXVH UGDWD





Figure 1. Key exchange between the firewalls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

VHFXULW\VSHFLILF LQIRUPDWLRQ PL[HG ZLWK WKH XVHU FHOOV DQG WKH EDQGZLGWK RULJLQDOO\ UHTXHVWHG E\ WKH FDOOHU KDV WREHH[WHQGHGWRPDNHSODFHIRUWKLVH[WUDLQIRUPDWLRQ :KHQ ):%  UHFHLYHG WKH 6(783¶ PHVVDJH LW FRPSXWHVDQGVWRUHVWKHDXWKHQWLFDWLRQLQIRUPDWLRQ$IWHU ):$  DQG ):%  H[FKDQJHG WKHLU NH\V ):$  PD\ SRVWHULRUO\VHQGWKHVLJQDWXUHRIWKH6(783¶PHVVDJH%\ WKLV ):%  ZLOO KDYH WKH RSSRUWXQLW\ WR FKHFN WKH LQWHJULW\ RI WKH 6(783¶ PHVVDJH EHIRUH DQ\ GDWD LV RIIHUHGWRWKHQHWZRUNDQGUHSXGLDWHWKHGHQLDORIVHUYLFH W\SHDWWDFNV 7KLV PHWKRG FDQ JXDUDQWHH WKH DQRQ\PLW\ RI WKH VHQGHU DQGRU UHFHLYHU >@>@ ):$  KDV WKH SRVVLELOLW\ WR UHSODFH WKH DGGUHVVHV RI WKH HQGSHHUV ZLWK WKH DGGUHVVHV RI WKH ILUHZDOOV DQG IRUZDUG WKH RULJLQDO DGGUHVVHVRQO\DIWHUWKHVHFXUHFRQHFWLRQLVHVWDEOLVKHG 

6HFXUH'DWD)RUZDUGLQJ 

7KH0RGLILHG$705HIHUHQFH0RGHOLQWKH )LUHZDOOV 

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

LPSOHPHQW D WXQQHO WKURXJK WKH SXEOLF $70 QHWZRUN UHPDLQLQJ µLQYLVLEOH¶ IRU WKH VLJQDOLQJ PHVVDJHV DQG WKH GDWD FHOOV 7KH FKDQJH LQ WKH PDQDJHPHQW SODQH DW WKH ILUHZDOOVLVUHTXLUHGWRVHWXSPDLQWDLQDQGUHOHDVHWKHVH WXQQHOV 7KH$70VHFXULW\VXEOD\HULVOLVWHQLQJWRWKHSDFNHWV DQG PHVVDJHV FRPLQJ IURP WKH 6$$/ OD\HU WKXV LW ZLOO NQRZ ZKHQ WKH FRQQHFWLRQ LV HVWDEOLVKHG 7KHQ LW PD\ VWDUW WR VHW XS WKH VHFXULW\ VHUYLFH ZLWK FRUUHVSRQGLQJ ILUHZDOO 7KH FHOOV XVHG IRU WKLV VHWXS ZH FDOOHG µVSHFLDO FHOOV¶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

7KH6SHFLDO&HOOV 

:H KDYH WR H[FKDQJH VHFXULW\ LQIRUPDWLRQV EHWZHHQ WKH ILUHZDOOV DQG WKH ILUHZDOOV KDYH WR GLIIHUHQWLDWH EHWZHHQ WKHVH DQG WKH XVHU GDWD 6LQFH WKH VHFXULW\ VXE OD\HULVLQWKH$70OD\HUZHDUHGHDOLQJZLWKFHOOV7KLV LVZK\WKHVHFXULW\LQIRUPDWLRQKDVWREHWUDQVSRUWHGDQG LGHQWLILHG RQ WKH FHOO OHYHO :H FDOOHG WKHVH FHOOV WKH µVSHFLDO FHOOV¶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

 7KH SHUIRUPDQFH HYDOXDWLRQ RI WKH SURWRFRO 

,QWKLVVHFWLRQZHSURYLGHDVLPXODWLRQEDVHGWHVWLQJRI WKH SHUIRUPDQFH LVVXHV UHODWHG WR RXU SURSRVDO :H PHQWHG WR VHHKRZPXFKWKHGHSOR\PHQWRIWKHILUHZDOOV LQDQ$70QHWZRUNDIIHFWWKHSHUIRUPDQFHSDUDPHWHUVRI WKHQHWZRUN 7KH WHVW WRSRORJ\ ZDV D EDFNERQH EDVHG $70 QHWZRUN7KHVZLWFKHVLQWKHEDFNERQHQHWZRUNIRUPHGD IXOO PHVK 7KH WUDIILF UHDFKHG WKH EDFNERQH WKURXJK DFFHVV$70VZLWFKHV(DFKDFFHVVVZLWFKZDVFRQQHFWHG WR WZR EDFNERQH QRGHV D WHFKQLTXH NQRZQ DV µGXDO KRPLQJ¶7KHUROHRIWKHGXDOKRPLQJZDVWRLPSURYHWKH UREXVWQHVV RI WKH QHWZRUN ,W DOVR KHOSV GLVWULEXWLQJ WKH LQFRPLQJ WUDIILF &KRRVLQJ WKLV WRSRORJ\ ZH LQWHQGHG WR VLPXODWH WKH EHKDYLRU RI D ±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



@ @  >  Q R L W D L U

D Y  K W G L Z G Q D %

 >  Q R L W D L U D Y  H P L W  J Q L U H I I

X %



% :  



3 X I I 7   > @

       









































 Figure 2. Optimising the additional bandwidth requested 1 U  R I F H O O V

by the special cells

ILUHZDOOVZLOOFDXVHDGUDVWLFDOLQFUHDVHLQFDOOUHMHFWLRQV ,QFDVHRIWKHILUHZDOOIUHHQHWZRUN )LJXUHSUHVHQWVWKHFDOOUHMHFWLRQFXUYHVIRUWKHWKUHH WUDIILF FODVVHV $ERYH  FDOOVVHF WKH FXUYH LV JURZLQJ IDVW ,I ZH LQWURGXFH WKH ILUHZDOOV LQ WKH QHWZRUN WKH FULWLFDO SRLQW UHPDLQV LQ WKH  FDOOVVHF UDQJH $OWKRXJK LQ WKLV ODWWHU FDVH WKH FXUYH JURZV IDVWHU LW LV VLWXDWHG LQ WKHEORFNLQJ]RQHWKXVLVLUUHOHYDQW 

&RQQHFWLRQ7LPH$QDO\VLV 



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

5HMH FWHG&DOOV



 

@ F H V

 V OO D F





P >  H  P L

G H W F  MH

7

H U  I R   U 1 









 























([ SRQ577): 3RO\)Z 5HM0ESV

3RO\1R)Z 5HM0ESV

3RO\)Z 5HM0ESV

3RO\)Z 5HM0ESV

3RO\1R)Z 5HM0ESV

3RO\1R)Z 5HM0ESV

Figure 3. Rejected Calls in the Network

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

5HMHFWHG&DOOV 

,Q RXU VLPXODWLRQ VFHQDULR WKH FDOO UHMHFWLRQ LV RQO\ FDXVHG E\ LQVXIILFLHQW EDQGZLGWK ,Q WKLV VHFWLRQ ZH H[DPLQHGZKHWKHUWKHEDQGZLGWKLQFUHDVHLQGXFHGE\WKH











1URIFDOOV >FDOOV V H F@

1URIFDOOV >FDOOV H F@

([ SRQ5771R):

Figure 4. Setup Time in the Network  'XULQJ RXU VLPXODWLRQV ZH KDYH IRXQG WKDW DOWKRXJK WKH ILUHZDOOV DSSUR[LPDWHO\ GRXEOHG WKH VHWXS WLPHV WKH WLPH FRQVWUDLQV KDYH QHYHU EHHQ YLRODWHG (YHQ LQ WKH EORFNLQJ]RQHWKHVHWXSWLPHVGLGQRWH[FHHGVHFRQGV 

(YDOXDWLRQRIWKH6LPXODWLRQ5HVXOWV 

,Q RXU VLPXODWLRQV WKH UHMHFWHG FDOOV ZHUH WKH FRQVHTXHQFHRIWKHODFNRIEDQGZLGWKRUWLPHUH[SLUDWLRQ 7KH QHWZRUN UHDFKHV WKH EORFNLQJ ]RQH DW DURXQG  PHVVDJHV  VHF 7KH FDOO UHMHFWLRQ GXH WR WKH EDQGZLGWK LQFUHDVHLPSRVHGE\ILUHZDOOVLVQRWVLJQLILFDQWVLQFHWKH ILUHZDOOIUHH QHWZRUN ZRXOG KDYH EHHQ DOUHDG\ HQWHUHG WKHEORFNLQJ]RQHDWVXFKDKLJKVLJQDOOLQJORDG 

&RQFOXVLRQV 

7KHSURSRVDOSUHVHQWHGLQWKLVSDSHUPDNHVLWSRVVLEOH WRLPSOHPHQWDVHFXULW\V\VWHPIRUWKH$70QHWZRUNV,W GRHV QRW UHTXLUH WKH PRGLILFDWLRQ RI WKH RWKHU $70

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

%LEOLRJUDSK\ 

>@ $70 )RUXP 6HFXULW\ :RUNLQJ *URXS ³$70 6HFXULW\ 6SHFLILFDWLRQ9HUVLRQ´$)6(&±)HEUXDU\  >@ 6WHYHQVRQ ' +LOOHU\ 1 DQG %\UG % ³6HFXUH &RPPXQLFDWLRQV LQ $70 1HWZRUNV´ &RPPXQLFDWLRQV RI $&09RO1R)HEUXDU\SS  >@/DXUHQW05ROLQ36WRIIHO/³6HFXULW\PHFKDQLVPZLWKLQ FRQWURO SODQH´ &RQWULEXWLRQ $70 )RUXP6DQ'LHJR &DOLIRUQLD)HEUXDU\  >@ /DXUHQW 0 3DXO 2 5ROLQ 3 ³6HFXULQJ &RPPXQLFDWLRQV RYHU $70 QHWZRUNV´ ,),36(&¶ &RSHQKDJHQ 'HQPDUN 0D\  >@'HQJ5+*RQJ//D]DU$$³6HFXULQJGDWDWUDQVIHULQ $V\QFKURQRXV 7UDQVIHU 0RGH QHWZRUNV´ 3URFHHGLQJ IURP *OREHFRP¶6LQJDSRUH1RYHPEHUSS  >@&KXDQJ 6 & ³6HFXULQJ $70 1HWZRUNV ³ 7KLUG $&0 FRQIHUHQFH RQ FRPSXWHU DQG FRPPXQLFDWLRQ VHFXULW\ 1HZ 'HOKL,QGLD  >@ 9DUDGKDUDMDQ 9 6KDQNDUDQ 5 +LWFKHQV 0 ³6HFXULW\ LVVXHV LQ $V\QFKURQRXV 7UDQVIHU 0RGH´ $70:25.6¶ 1HZ=HDODQG)HEUXDU\  >@ &DUR]]L 0 7 -DHJHU ) 5 6DQMRXU - ³$70 )LUHZDOO 3HUIRUPDQFH (YDOXDWLRQ´ )LQDO 3URMHFW 5HSRUW 8QLYHUVLW\ RI 0DU\ODQGKWWSZZZHQJXPGHGXSHRSOHFDUR]]LSURMHFWKWPO 

>@ ³(QFU\SWLQJ $70 )LUHZDOO´ :KLWH 3DSHU 6HFDQW 1HWZRUN 7HFKQRORJLHV KWWSZZZVHDQWQHWFRPDUWLFOHVZLQNZLQNKWPO  >@ 6]pNHO\ 6 0ROGRYiQ , 6LPRQ &V ³2YHUORDG JHQHUDWHG E\ VLJQDOOLQJ PHVVDJH IORZV LQ $70 QHWZRUNV´ ,),3 /XQG 6ZHGHQ0D\  >@ 6]pNHO\ &V 6LPRQ * 6]FV ³3HUIRUPDQFH $QDO\VLV RI 6ZLWFKHG 9LUWXDO &RQQHFWLRQV LQ $70 1HWZRUNV´ WK ,),3 :RUNVKRS RQ 3HUIRUPDQFH 0RGHOOLQJ DQG (YDOXDWLRQ RI $70 1HWZRUNV 30($1  ,ONOH\ 8QLWHG .LQJGRP  -XO\   >@ 6FKQHLGHU % ³$SSOLHG FU\SWRJUDSK\ SURWRFROV DOJRULWKPVDQGVRXUFHFRGHLQ&´9ROXPH,6%1 -RKQ:LOH\ 6RQV  >@ 7RXFK - ' ³3HUIRUPDQFH $QDO\VLV RI 0'´ ZRUNLQJ GUDIW $GYDQFHG 5HVHDUFK 3URMHFWV $JHQF\ ³1HWVWDWLRQ $UFKLWHFWXUHDQG$GYDQFHG$WRPLF1HWZRUN´SURMHFW  >@3U\FNHUGH0³$V\QFKURQRXV7UDQVIHU0RGH6ROXWLRQIRU %URDGEDQG,6'1´(OOLV+RUZRRG  >@ 3H\UDYLDQ 0 ³$ )UDPHZRUN IRU $XWKHQWLFDWHG .H\ 'LVWULEXWLRQLQ$701HWZRUNV´$70)RUXP  >@ $70 )RUXP ³$70 8VHU1HWZRUN ,QWHUIDFH 6SHFLILFDWLRQ´YHUVLRQ  >@ &KHVZLFN : 5 %HOORYLQ 6 0 ³)LUHZDOOV DQG ,QWHUQHW 6HFXULW\ 5HSHOOLQJ WKH :LOO\ +DFNHU´ $GGLVRQ:HVOH\ $SULO   >@ 3H\UDYLDQ 0 ³$70 VHFXULW\ VFRSH DQG UHTXLUHPHQWV´ $70)RUXP  >@ %HOODUH 0 *XHULQ 5 5RJDZD\ 3 ³;25 0$&V 1HZ 0HWKRGV IRU 0HVVDJH $XWKHQWLFDWLRQ 8VLQJ )LQLWH 3VHXGRUDQGRP )XQFWLRQV´ $GYDQFHV LQ &U\SWRORJ\&U\SWR  3URFHHGLQJV6SULQJHU9HUODJ 

$SSHQGL[ 7KH ORJLFDO VWUXFWXUH RI WKH VSHFLDO FHOOV $70FHOOKHDGHU

6SHFLDOFHOO

3D\ORDG

,'

W\SH

/HQJWK

6SHFLDOFHOO 3D\ORDG

&5&

$70FHOOSD\ORDG

D 7KHILUVWVSHFLDOFHOOLQDFRPPXQLFDWLRQ

$70FHOOKHDGHU

6SHFLDOFHOO

3D\ORDG

6HTXHQFH

6SHFLDOFHOO

,'

W\SH

QU

3D\ORDG

$70FHOOSD\ORDG

E 7KHIROORZLQJVSHFLDOFHOOVLQWKHFRPPXQLFDWLRQ



&5&