Masu bincike daga rukunin NCC rauni () a cikin kwakwalwan kwamfuta na Qualcomm, wanda ke ba ku damar tantance abubuwan da ke cikin maɓallan ɓoye masu zaman kansu waɗanda ke cikin keɓantaccen mahallin Qualcomm QSEE (Qualcomm Secure Execution Environment), dangane da fasahar ARM TrustZone. Matsalar ta bayyana kanta a ciki Snapdragon SoC, wanda ya zama tartsatsi a cikin wayoyin hannu bisa tsarin Android. Gyaran da ke gyara matsalar sun rigaya a cikin sabuntawar Android na Afrilu da sabbin fitowar firmware don kwakwalwan kwamfuta na Qualcomm. Ya ɗauki Qualcomm fiye da shekara guda don shirya gyara; bayanin game da raunin da aka fara aika zuwa Qualcomm a kan Maris 19, 2018.
Bari mu tuna cewa fasahar ARM TrustZone tana ba ku damar ƙirƙira keɓantaccen mahalli na kayan masarufi waɗanda suka rabu gaba ɗaya daga babban tsarin kuma suna aiki akan na'ura mai ƙira ta daban ta amfani da keɓantaccen tsarin aiki na musamman. Babban manufar TrustZone ita ce samar da keɓantaccen kisa na masu sarrafawa don maɓallan ɓoyewa, tantancewar biometric, bayanan biyan kuɗi da sauran bayanan sirri. Ana yin hulɗa tare da babban OS a kaikaice ta hanyar hanyar aikawa. Ana adana maɓallan ɓoyewa masu zaman kansu a cikin keɓaɓɓen kantin kayan masarufi, waɗanda, idan aka aiwatar da su yadda ya kamata, za su iya hana yaɗuwar su idan tsarin da ke ƙasa ya lalace.
Lalacewar ta samo asali ne saboda aibi a cikin aiwatar da tsarin sarrafa lanƙwasa elliptical, wanda ya haifar da zubewar bayanai game da ci gaban sarrafa bayanai. Masu bincike sun ƙirƙiro wata dabarar kai hari ta tashar ta gefe wacce ke ba da damar yin amfani da ɗigogi na kai tsaye don dawo da abubuwan da ke cikin maɓallai masu zaman kansu waɗanda ke cikin keɓewar kayan aiki. . Ana ƙididdige leaks bisa nazarin ayyukan toshe tsinkayar reshe da canje-canje a lokacin samun damar bayanai a cikin ƙwaƙwalwar ajiya. A cikin gwajin, masu binciken sun yi nasarar nuna nasarar dawo da maɓallan ECDSA 224- da 256-bit daga maɓallan maɓalli na keɓaɓɓen kayan aiki da aka yi amfani da su a cikin wayar Nexus 5X. Maido da maɓallin da ake buƙata don samar da sa hannun dijital kusan dubu 12, wanda ya ɗauki fiye da sa'o'i 14. Kayayyakin da aka yi amfani da su wajen kai harin .
Babban abin da ke haifar da matsala shine raba kayan aikin kayan aiki na yau da kullun da cache don ƙididdigewa a cikin TrustZone da kuma a cikin babban tsarin - ana yin keɓewa a matakin rarrabuwa na ma'ana, amma ta amfani da raka'o'in ƙididdiga na gama gari tare da alamun ƙididdiga da bayanai game da reshe. adiresoshin da ake ajiyewa a cikin cache na gama gari. Yin amfani da hanyar Prime + Probe, dangane da kimanta canje-canje a lokacin samun damar bayanan da aka adana, yana yiwuwa, ta hanyar duba kasancewar wasu alamu a cikin cache, don saka idanu kan kwararar bayanai da alamun aiwatar da lambar da ke da alaƙa da lissafin sa hannun dijital a ciki. TrustZone tare da daidaitattun daidaito.
Yawancin lokaci don samar da sa hannu na dijital ta amfani da maɓallan ECDSA a cikin kwakwalwan Qualcomm ana kashe su don yin ayyukan ninkawa a cikin madauki ta amfani da vector na farawa wanda ba ya canzawa ga kowane sa hannu (). Idan maharin zai iya murmurewa aƙalla ƴan kaɗan tare da bayani game da wannan vector, zai yiwu a kai hari don maido da maɓalli na sirri a jere.
A cikin yanayin Qualcomm, an gano wurare guda biyu da irin waɗannan bayanan aka bazu a cikin algorithm na ninkawa: lokacin da ake gudanar da ayyukan bincike a cikin tebur da kuma a cikin lambar dawo da bayanan sharaɗi dangane da ƙimar ɗan ƙarshe a cikin vector "nonce". Duk da gaskiyar cewa lambar Qualcomm ta ƙunshi matakan da za a magance leaks ɗin bayanai ta hanyar tashoshi na ɓangare na uku, hanyar da aka haɓaka ta hanyar kai hari tana ba ku damar ƙetare waɗannan matakan kuma ku tantance ragi da yawa na ƙimar "nonce", waɗanda suka isa dawo da maɓallan 256-bit ECDSA.
source: budenet.ru