{"id":82556,"date":"2020-05-22T19:41:55","date_gmt":"2020-05-22T17:41:55","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc"},"modified":"2020-05-22T19:41:55","modified_gmt":"2020-05-22T17:41:55","slug":"kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hr\/blog\/news\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","title":{"rendered":"Kriti\u010dna ranjivost u implementaciji funkcije memcpy za ARMv7 u Glibc-u","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Sigurnosni istra\u017eitelji iz kompanije Cisco otkrili su<\/a><\/noindex> detalji ranjivosti<\/a><\/noindex> (CVE-2020-6096<\/a><\/noindex>) u implementaciji funkcije memcpy() koja se pru\u017ea u Glibc za 32-bitnu platformu ARMv7. Problem je uzrokovan nepravilnim rukovanjem negativnim vrijednostima parametra koji odre\u0111uje veli\u010dinu kopirane oblasti, zbog kori\u0161tenja optimizacija u asembleru koje manipuliraju potpisanim 32-bitnim cjelobrojnim vrijednostima. Poziv memcpy() na ARMv7 sistemima s negativnom veli\u010dinom dovodi do neispravnog usporedbe vrijednosti i pisanja izvan granica navedenog bafera.<\/p>\n

Ranljivost se mo\u017ee iskoristiti za izvr\u0161avanje koda u situaciji kada napada\u010d mo\u017ee stvoriti negativnu vrijednost varijable koja prenosi veli\u010dinu podataka koji se kopiraju (na primjer, prilikom prijenosa vi\u0161e od 2 GB podataka, dolazi do negativne vrijednosti, ali tijekom napada potrebno je pro\u0107i najmanje 4 GB kako bi se pre\u0161lo granice bafera). Funkcija memcpy() se aktivno koristi u aplikacijama, a ARMv7 procesori su ra\u0161ireni u automobilskim sistemima, mobilnim, industrijskim, potro\u0161a\u010dkim, komunikacijskim i ugra\u0111enim ure\u0111ajima koji potencijalno mogu postati meta napada koriste\u0107i Bluetooth, HD Radio\/DAB, USB, CAN bus, Wi-Fi i druge vanjske izvore podataka (na primjer, mogu se napasti mre\u017eno dostupne usluge i aplikacije koje primaju ulazne podatke bez ograni\u010denja veli\u010dine).<\/p>\n

Kao primjer navodi se kreiranje radnog eksploita za napad na ugra\u0111eni http-server u automobilskim informacijskim sistemima, dostupan putem automobilske Wi-Fi mre\u017ee. Strani napada\u010d mo\u017ee iskoristiti ranjivost u memcpy u ovom serveru slanjem vrlo velikog GET zahtjeva i dobiti root pristup sistemu.<\/p>\n

\"Kriti\u010dna<\/a><\/noindex><\/center><\/p>\n

Na 32-bitnim x86 sistemima problem se ne manifestira, jer implementacija memcpy za ovu arhitekturu ispravno interpretira varijablu s veli\u010dinom kao bezsigniranu cjelobrojnu vrijednost tipa size_t (u napisanom asembleru implementaciji<\/a><\/noindex> za ARMv7 umjesto size_t obra\u0111uje se kao potpisano cjelobrojno). Ispravka je trenutno dostupna u obliku zakrpe<\/a><\/noindex>, koja \u0107e biti uklju\u010dena u augursko a\u017euriranje Glibc 2.32.
\nIspravka se svodi na zamjenu kori\u0161tenja asemberskih instrukcija koje rade s potpisanim operandima (bge i blt) s bezsigniranim analogama (blo i bhs). <\/p>\n

Problem jo\u0161 nije rije\u0161en u Debian 9 i 10<\/a><\/noindex> (u Debianu 8 se ne pojavljuje), Fedora<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, OpenEmbedded, Tizen (koristi glibc). RHEL<\/a><\/noindex> i SUSE<\/a><\/noindex> problem ne poga\u0111a, jer oni ne podr\u017eavaju 32-bitne ARMv7 sustave. Android nije pogo\u0111en ranjivo\u0161\u0107u, jer koristi vlastitu implementaciju libc (Bionic). U OpenWRT<\/a><\/noindex> ve\u0107ini izdanja po defaultu koristi se Musl, ali u repozitoriju se nalazi i glibc.<\/p>\n

<\/a><\/noindex><\/p>\n

Izvor: opennet.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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[…]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":82557,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-82556","post","type-post","status-publish","format-standard","has-post-thumbnail","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\udd47Kriti\u010dna ranjivost u implementaciji funkcije memcpy za ARMv7 unutar Glibc | ProHoster","description":"Istra\u017eiva\u010di sigurnosti iz tvrtke Cisco otkrili su 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