I-Marvin iyimbuyiselo yokuba sengozini eneminyaka engu-25 ubudala evumela ukusayinda kwe-RSA kanye nokusebenza kokukhishwa kwemfihlo.
Ngesikhathi se-ESORICS 2023 (i-European Symposium on Computer Security Research) ebibanjwe kusukela mhla zingama-25 kuya kumhla zingama-29 kuMandulo eNetherlands, umcwaningi wezokuphepha osebenzela i-Red Hat wethule i-"Marvin Attack," indlela yokuhlasela evumela ukunqunywa kwedatha yokuqala ngokulinganisa ukubambezeleka ngesikhathi sokusebenza kokubethela ngokusekelwe ku-algorithm ye-RSA.
I-Marvin Attack iyindlela ehlukile yendlela ye-Bleichenbacher, eyaphakanyiswa ngo-1998 , futhi iyaqhubeka nokuthuthukiswa kokuhlaselwa kwe-ROBOT kanye ne-New CAT okwanyatheliswa ngo-2017 nango-2019.
Ukuhlasela kuka-Marvin kuwukubuyiselwa kokuba sengozini kweminyaka engu-25 ubudala okuvumela ukusayinda kwe-RSA nemisebenzi yokususa ukubethela ukuze kwenziwe njengomhlaseli onekhono lokubona kuphela isikhathi sokusebenza kokukhishwa kwemfihlo okwenziwa ngokhiye oyimfihlo.
Ngo-1998, u-Daniel Bleichenbacher wathola ukuthi imilayezo yephutha ehlinzekwe yiziphakeli ze-SSL ngamaphutha ku-PKCS #1 v1.5 padding inike amandla ukuhlaselwa kwe-ciphertext okukhethiwe; Lokhu kuhlasela kwephula ngokuphelele ubumfihlo be-TLS uma kusetshenziswa nokubethela kwe-RSA. Ngo-2018, u-Hanno Böck, u-Juraj Somorovsky kanye no-Craig Young babonise eminyakeni engu-19 kamuva ukuthi amaseva amaningi e-inthanethi ayesesengozini yokuhluka okuncane kokuhlasela kwasekuqaleni.
Ngokuyisisekelo, le ndlela ihilela umhlaseli, ngokusekelwe ekuphenduleni okuhlukile kweseva kanye nezikhathi zokusebenzisa, angahlukanisa amabhlogo e-Oracle afanele nangalungile angeziwe kusetshenziswa indinganiso ye-PKCS #1 v1.5 ukuze avumelanise idatha ebethelwe eceleni komngcele webhloko. Ngokusebenzisa ulwazi mayelana nokunemba kwamabhlogo okunamathisela, umhlaseli angasebenzisa amandla aluhlaza ukuze aphinde abhale umbhalo ovumelekile.
Kulesi simo, ukuhlasela akubuyiseli ngqo ukhiye oyimfihlo; kuvumela kuphela ukuguqulelwa kombhalo oyimfihlo noma ukwenziwa komlayezo osayiniwe oqanjiwe. Ukuze kufezwe ukuhlasela okuphumelelayo, kumele kuthunyelwe inani elikhulu kakhulu lemiyalezo yokuhlola ukuze kuguqulelwe kombhalo oyimfihlo.
Ukusebenzisa ukuhlasela amaseva e-TLS asebenzisa ukubethela okusekelwe ku-RSA kuvumela umhlaseli ukuthi agcine ithrafikhi evinjiwe ngaphandle kokuphazamisa bese eyisusa . Kumaseva asekela i-PFS, ukwenza ukuhlasela kuba nzima kakhulu, futhi impumelelo incike ekutheni ukuhlasela kwenziwa ngokushesha kangakanani.
Ngaphezu kwalokho, le ndlela ivumela ukukhiqiza isiginesha yedijithali engelona iqiniso eqinisekisa okuqukethwe kwemiyalezo ye-ServerKeyExchange ku-TLS 1.2 noma imiyalezo ye-CertificateVerify ku-TLS 1.3 edluliselwe ngesikhathi sesigaba sokushintshana ngokhiye, esingasetshenziswa ukwenza ukuhlaselwa kwe-MITM ukuze kuvinjelwe uxhumano lwe-TLS phakathi kweklayenti neseva.
Kuthiwa umehluko phakathi kwendlela ye-Marvin uncike kubuchwepheshe obuthuthukisiwe bokuhlukanisa idatha ekhuphukayo elungile nengalungile , ukuhlunga ama-positive angamanga, ukunquma ngokunembile ukubambezeleka kokubala, kanye nokusebenzisa iziteshi ezengeziwe zenkampani yangaphandle ngesikhathi sokulinganisa.
Empeleni, indlela ehlongozwayo ivumela ukususa ukubethela kwethrafikhi noma ukukhiqiza amasiginesha edijithali ngaphandle kokwazi ukhiye oyimfihlo we-RSA. Ukuhlola ukusebenza kokuhlasela, iskripthi esikhethekile sokuhlola amaseva we-TLS namathuluzi okuhlonza izinkinga kumalabhulali ashicilelwe.
Inkinga ithinta ukusetshenziswa kwephrothokholi okuningana okusebenzisa i-RSA kanye ne-PKCS . Nakuba imitapo yolwazi yesimanje ye-cryptographic iqukethe isivikelo esithile ekuhlaselweni okusekelwe endleleni ye-Bleichenbacher, ucwaningo luveze ukuthi lawa ma-library aneziteshi ezivulekile zokuvuza futhi awanikezi isikhathi sokucubungula esihambisanayo samaphakethe ane-padding efanele nengalungile. Isibonelo, ukusetshenziswa kukaMarvin kokuhlasela kwe-GnuTLS akuboshelwe kukhodi eyenza ngqo izibalo ezihlobene ne-RSA, kodwa kunalokho kusebenzisa izikhathi ezahlukene zokusebenzisa ikhodi enquma ukuthi kufanele ibonise yini umlayezo othile wephutha.
Umbhali wocwaningo futhi ukholelwa ukuthi isigaba sobungozi esicatshangelwayo asikhawulelwe ku-RSA futhi singase sithinte ama-algorithms amaningi e-cryptographic ancike kumalabhulali ajwayelekile ukuze kube nezibalo eziphelele.
Ukuqinisekisa ukuthi kungenzeka ukwenza ukuhlasela kukaMarvin ngokusebenza, umcwaningi ubonise ukusebenza kwendlela kuzinhlelo zokusebenza ezisuselwa kumtapo wolwazi we-M2Crypto kanye ne-pyca/cryptography, lapho amahora ambalwa anele ngokwanele ukufaka engcupheni ukubethela ngokwenza ucwaningo i-laptop evamile.
Okokugcina, uma unesithakazelo sokufunda okwengeziwe, ungathola imininingwane kusixhumanisi esilandelayo.