Otkrivena je informacija o ranjivosti (CVE-2021-33164) u UEFI firmware-u, koja omogu\u0107uje izvr\u0161enje koda na razini SMM (System Management Mode), koja je prioritetnija od hypervisor mode i za\u0161titnog nultog prstena, te pru\u017ea neograni\u010den pristup cijeloj sistemskoj memoriji. Ranjivost, koja nosi kodno ime RingHopper, povezana je s mogu\u0107no\u0161\u0107u provo\u0111enja napada pomo\u0107u DMA (Direct Memory Access) za o\u0161te\u0107enje memorije u kodu koji se izvr\u0161ava na razini SMM. Prisutnost ranjivosti potvr\u0111ena je u firmware-u Intel, Dell i Insyde Software (navodno, problem se ti\u010de 8 proizvo\u0111a\u010da, ali ostala 5 za sada nije objavljena). Firmware AMD, Phoenix i Toshiba nisu pogo\u0111eni problemom. <\/p>\n
Eksploatacija ranjivosti mo\u017ee se provesti iz operativnog sistema, koriste\u0107i ranjive SMI handler-e (System Management Interrupt), za pristup kojima su potrebna administratorska prava. Napad se tako\u0111er mo\u017ee provesti ukoliko postoji fizi\u010dki pristup u ranoj fazi pokretanja, prije inicializacije operativnog sistema. Da bi se blokirao problem, korisnicima Linuxa preporu\u010duje se a\u017euriranje firmware-a putem LVFS (Linux Vendor Firmware Service), koriste\u0107i alat fwupdmgr (fwupdmgr get-updates; fwupdmgr update) iz paketa fwupd. <\/p>\n
Potrebna su administratorska prava za provo\u0111enje napada \u0161to ograni\u010dava opasnost problema, ali ne sprje\u010dava njegovo kori\u0161tenje kao ranjivosti drugog reda, za odr\u017eavanje prisutnosti nakon eksploatacije drugih ranjivosti u sistemu ili primjene metoda socijalnog in\u017eenjeringa. Pristup SMM (Ring -2) omogu\u0107uje izvr\u0161enje koda na razini koja nije pod kontrolom operativnog sistema, \u0161to se mo\u017ee iskoristiti za modifikaciju firmware-a i smje\u0161tanje skrivene zlo\u0107udne koda ili rootkita u SPI Flash, koji nisu detektirani iz operativnog sistema, kao i za isklju\u010divanje verifikacije tokom pokretanja (UEFI Secure Boot, Intel BootGuard) i napade na hypervisore radi zaobila\u017eenja mehanizama za provjeru integriteta virtuelnih okru\u017eenja. <\/p>\n
Probleme je uzrokovano stanjem utrke u SMI (System Management Interrupt) upravlja\u010du, koje se javlja u trenutku izme\u0111u provjere pristupa i upoznavanja sa SMRAM-om. Za odre\u0111ivanje pravog trenutka izme\u0111u provjere stanja i kori\u0161tenja rezultata provjere mo\u017ee se koristiti analiza putem vanjskih kanala pomo\u0107u DMA. Kao rezultat, zbog asinkrone prirode pristupa SMRAM-u putem DMA, napada\u010d mo\u017ee odrediti pravi trenutak i prepisati sadr\u017eaj SMRAM-a, koriste\u0107i DMA, izbjegavaju\u0107i SMI upravlja\u010dki API. Procesori koji podr\u017eavaju mehanizme Intel-VT i Intel VT-d uklju\u010duju za\u0161titu od DMA napada, temeljen na primjeni IOMMU (Input-Output Memory Management Unit), ali ova za\u0161tita je u\u010dinkovita samo za blokiranje hardverskih DMA napada provedenih pomo\u0107u pripremljenih ure\u0111aja od strane napada\u010da i ne \u0161titi od napada putem SMI upravlja\u010da. \u0420\u0430\u0441\u043a\u0440\u044b\u0442\u0430 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2021-33164) \u0432 \u043f\u0440\u043e\u0448\u0438\u0432\u043a\u0430\u0445 UEFI, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 SMM (System Management Mode), \u0431\u043e\u043b\u0435\u0435 \u043f\u0440\u0438\u043e\u0440\u0438\u0442\u0435\u0442\u043d\u043e\u043c, \u0447\u0435\u043c \u0440\u0435\u0436\u0438\u043c \u0433\u0438\u043f\u0435\u0440\u0432\u0438\u0437\u043e\u0440\u0430 \u0438 \u043d\u0443\u043b\u0435\u0432\u043e\u0435 \u043a\u043e\u043b\u044c\u0446\u043e \u0437\u0430\u0449\u0438\u0442\u044b, \u0438 \u043f\u0440\u0435\u0434\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u044e\u0449\u0435\u043c \u043d\u0435\u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u043d\u044b\u0439 \u0434\u043e\u0441\u0442\u0443\u043f \u043a\u043e \u0432\u0441\u0435\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u0439 \u043f\u0430\u043c\u044f\u0442\u0438. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c, \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043f\u043e\u043b\u0443\u0447\u0438\u043b\u0430 \u043a\u043e\u0434\u043e\u0432\u043e\u0435 \u0438\u043c\u044f RingHopper, \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c\u044e \u043f\u0440\u043e\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u0430\u0442\u0430\u043a\u0438 \u043f\u043e \u0432\u0440\u0435\u043c\u0435\u043d\u0438 \u043f\u0440\u0438 \u043f\u043e\u043c\u043e\u0449\u0438 DMA (Direct Memory Access) \u0434\u043b\u044f \u043f\u043e\u0432\u0440\u0435\u0436\u0434\u0435\u043d\u0438\u044f […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-105506","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Ranjivost u UEFI firmverima, koja omogu\u0107ava izvr\u0161avanje koda na razini SMM | ProHoster","description":"Otkrivena je ranjivost (CVE-2021-33164) u UEFI firmverima, koja omogu\u0107ava izvr\u0161avanje koda na razini SMM (System Management Mode), koja ima vi\u0161i prioritet od hipervizorske razine i sigurnosnog nultog prstena.","canonical_url":"https:\/\/prohoster.info\/hr\/blog\/news\/uyazvimost-v-proshivkah-uefi-pozvolyayushhaya-vypolnit-kod-na-urovne-smm","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"hr_HR","og:site_name":"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b","og:type":"article","og:title":"\ud83e\udd47\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 \u043f\u0440\u043e\u0448\u0438\u0432\u043a\u0430\u0445 UEFI, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 SMM | ProHoster","og:description":"\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u0430 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2021-33164) \u0432 \u043f\u0440\u043e\u0448\u0438\u0432\u043a\u0430\u0445 UEFI, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u043d\u0430 \u0443\u0440\u043e\u0432\u043d\u0435 SMM (System Management Mode), \u0431\u043e\u043b\u0435\u0435 \u043f\u0440\u0438\u043e\u0440\u0438\u0442\u0435\u0442\u043d\u043e\u043c, \u0447\u0435\u043c \u0440\u0435\u0436\u0438\u043c \u0433\u0438\u043f\u0435\u0440\u0432\u0438\u0437\u043e\u0440\u0430 \u0438 \u043d\u0443\u043b\u0435\u0432\u043e\u0435 \u043a\u043e\u043b\u044c\u0446\u043e \u0437\u0430\u0449\u0438\u0442\u044b, \u0438.","og:url":"https:\/\/prohoster.info\/hr\/blog\/news\/uyazvimost-v-proshivkah-uefi-pozvolyayushhaya-vypolnit-kod-na-urovne-smm","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2022-11-09T01:36:39+00:00","article:modified_time":"2022-11-09T01:36:39+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":[],"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/posts\/105506","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/comments?post=105506"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/posts\/105506\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/media?parent=105506"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/categories?post=105506"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/hr\/wp-json\/wp\/v2\/tags?post=105506"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
Izvor: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"