Wani rukuni na masu bincike daga Jami'ar Free University of Amsterdam sun kirkiro wani sabon salo na harin RowHammer, hakan yana ba da damar sauya abun cikin kowane ragowa a ƙwaƙwalwar ajiya dangane da kwakwalwan DRAM, don kare mutuncin lambobin gyaran kuskure (ECC) waɗanda ake amfani da su.
Ana iya aiwatar da harin daga nesa tare da samun dama ga tsarinKamar yadda raunin RowHammer zai iya jirkita abubuwan da kowane ɗan ragowa yake da shi a ƙwaƙwalwar ta hanyar karanta bayanai ta kowane lokaci daga ƙwayoyin ƙwaƙwalwar maƙwabta.
Menene raunin RowHammer?
Zuwa ga abin da ƙungiyar masu bincike suka bayyana game da raunin RowHammer, shine wannan se dangane da tsarin ƙwaƙwalwar DRAM, saboda asali wannan matrix mai girman sifa ce wacce kowane ɗayan waɗannan ƙwayoyin suke ƙunshe da mai kwakwalwa da kuma transistor.
Don haka ci gaba da karatu na yanki guda na ƙwaƙwalwar yana haifar da jujjuyawar lantarki da rikice-rikice waɗanda ke haifar da ɗan asarar caji a cikin ƙwayoyin maƙwabta.
Idan ƙarfin karatun ya isa sosai, tantanin halitta na iya rasa cikakken adadin caji kuma sake zagayowar sake sabuntawa na gaba ba zai sami lokacin dawo da asalin sa ba, wanda zai haifar da canji a ƙimar bayanan da aka adana. A cikin tantanin halitta.
Wani sabon nau'in RowHammer
Har yanzu, ta amfani da ECC an ɗauke ta hanyar da ta fi amintacciya don kariya daga matsalolin da aka bayyana a sama.
Pero masu binciken sun yi nasarar kirkirar wata hanya don sauya kayyadadden kwakwalwar da aka ayyana hakan bai kunna hanyar gyara kuskure ba.
Hanyar ana iya amfani dasu akan sabobin tare da ƙwaƙwalwar ECC don gyara bayanai, maye gurbin mummunar lambar kuma canza haƙƙin samun dama.
Misali, a cikin hare-haren RowHammer da aka nuna a sama, lokacin da wani mai kai hari ya sami damar amfani da wata na’ura mai inganci, an zazzage sabuntar tsarin ta hanyar sauye-sauye cikin tsarin sunan mai masauki don zazzagewa da gyaggyara hanyoyin tabbatar da sunan mai masauki.
Ta yaya wannan sabon bambancin ke aiki?
Abin da masu binciken suka yi bayani a kai wannan sabon harin shine cewa hanyar ECC ta dogara da siffofin gyaran kuskure- Idan aka canza abu daya, ECC zai gyara kuskuren, idan aka daga bits biyu, to za a jefa banda kuma za a dakatar da shirin da karfin tsiya, amma idan an canza bits uku a lokaci daya, ECC na iya lura da gyaran.
Don ƙayyade yanayin da tabbacin ECC baya aiki, An ƙaddamar da hanyar tabbatarwa mai kama da ta tseren wanda ke ba da damar kimanta yiwuwar kai hari ga takamaiman adireshin cikin ƙwaƙwalwa.
Hanyar ta dogara ne da cewa, yayin gyara kuskure, lokacin karatu yana ƙaruwa kuma sakamakon jinkirin yana da ma'ana da sananne.
Harin ya ragu zuwa ƙoƙari na gaba don sauya kowane abu daban-daban, ƙayyade nasarar canjin ta bayyanar da jinkiri da aka samu ta hanyar saitin ECC.
Sabili da haka, ana bincika kalmar kalma tare da ragowa masu canji uku. A matakin karshe, ya zama dole a tabbatar cewa ragowa uku masu canzawa a wurare biyu sun bambanta, sannan kuma a yi ƙoƙarin canza ƙimar su a hanya guda.
Game da demo
da Masu bincike sunyi nasarar nuna yiwuwar kai hari kan sabar daban daban tare da ƙwaƙwalwar DDR3 (bisa ka'ida mai rauni da kuma DDR4 ƙwaƙwalwar ajiya), uku daga cikinsu an sanye su da masu sarrafa Intel (E3-1270 v3, Xeon E5-2650 v1, Intel Xeon E5-2620 v1), da AMD ɗaya (Opteron 6376).
En Zanga-zangar ta nuna cewa gano haɗin haɗin da ake buƙata a cikin lab a kan sabar da ba ta aiki yakan ɗauki minti 32.
Yin kai hari kan sabar da ke gudana ta fi wuya saboda kasancewar tsangwama da ya taso daga aikin aikace-aikacen.
A cikin tsarin samarwa, zai iya ɗaukar mako guda don nemo haɗin haɗin da ake buƙata na musayar ragowa.