{"id":114955,"date":"2024-04-09T21:31:00","date_gmt":"2024-04-09T19:31:00","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/novyj-variant-ataki-bhi-na-cpu-intel-pozvolyayushhij-obojti-zashhitu-v-yadre-linux"},"modified":"2024-04-09T21:31:00","modified_gmt":"2024-04-09T19:31:00","slug":"novyj-variant-ataki-bhi-na-cpu-intel-pozvolyayushhij-obojti-zashhitu-v-yadre-linux","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/novyj-variant-ataki-bhi-na-cpu-intel-pozvolyayushhij-obojti-zashhitu-v-yadre-linux","title":{"rendered":"Nov\u00e1 varianta \u00fatoku BHI na CPU Intel, kter\u00e1 umo\u017e\u0148uje obch\u00e1zen\u00ed ochrany v j\u00e1dru Linuxu","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Skupina v\u00fdzkumn\u00edk\u016f z Amsterdamsk\u00e9 svobodn\u00e9 univerzity objevila novou metodu \u00fatoku \u201eNative BHI\u201c (CVE-2024-2201), kter\u00e1 umo\u017e\u0148uje na syst\u00e9mech s procesory Intel ur\u010dit obsah pam\u011bti j\u00e1dra Linux p\u0159i prov\u00e1d\u011bn\u00ed exploitu v u\u017eivatelsk\u00e9m prostoru. V p\u0159\u00edpad\u011b aplikace \u00fatoku na virtualiza\u010dn\u00ed syst\u00e9my m\u016f\u017ee \u00fato\u010dn\u00edk z hostitelsk\u00e9ho syst\u00e9mu zjistit obsah pam\u011bti hostitelsk\u00e9ho prost\u0159ed\u00ed nebo jin\u00fdch hostitelsk\u00fdch syst\u00e9m\u016f. <\/p>\n

Metoda Native BHI nab\u00edz\u00ed jinou techniku exploitace zranitelnosti BHI (Branch History Injection, CVE-2022-0001), kter\u00e1 obch\u00e1z\u00ed d\u0159\u00edve zaveden\u00e9 zp\u016fsoby ochrany. Navr\u017een\u00e1 v roce 2022 metoda \u00fatoku BHI p\u0159edpokl\u00e1dala exploitaci zranitelnosti v r\u00e1mci jednoho stupn\u011b privilegi\u00ed, p\u0159i\u010dem\u017e exploit byl zalo\u017een na prov\u00e1d\u011bn\u00ed programu eBPF, kter\u00fd byl u\u017eivateli na\u010dten v j\u00e1d\u0159e. K zablokov\u00e1n\u00ed zranitelnosti sta\u010dilo omezit p\u0159\u00edstup k prov\u00e1d\u011bn\u00ed k\u00f3du eBPF pro b\u011b\u017en\u00e9 u\u017eivatele. <\/p>\n

Nov\u00e1 metoda Native BHI nevy\u017eaduje p\u0159\u00edstup k eBPF a umo\u017e\u0148uje \u00fatok nepriviligovan\u00e9mu u\u017eivateli z u\u017eivatelsk\u00e9ho prostoru. Metoda se zakl\u00e1d\u00e1 na prov\u00e1d\u011bn\u00ed existuj\u00edc\u00edch gadget\u016f v k\u00f3du j\u00e1dra \u2014 sekvenc\u00ed p\u0159\u00edkaz\u016f vedouc\u00edch k spekulativn\u00edmu prov\u00e1d\u011bn\u00ed instrukc\u00ed. Pro vyhled\u00e1v\u00e1n\u00ed vhodn\u00fdch gadget\u016f v j\u00e1dru byl vyvinut speci\u00e1ln\u00ed n\u00e1stroj InSpectre Gadget, kter\u00fd p\u0159i anal\u00fdze j\u00e1dra 6.6-rc4 identifikoval 1511 Spectre gadget\u016f a 2105 pomocn\u00fdch gadget\u016f spr\u00e1vy.

\"Nov\u00e1<\/center> <\/p>\n

Na z\u00e1klad\u011b nalezen\u00fdch gadget\u016f v\u00fdzkumn\u00edci vytvo\u0159ili exploit, kter\u00fd umo\u017e\u0148uje extrahovat z pam\u011b\u0165ov\u00fdch oblast\u00ed j\u00e1dra \u0159et\u011bzec s hashov\u00e1n\u00edm hesla u\u017eivatele root, na\u010dten\u00e9ho z souboru \/etc\/shadow. Rychlost extrakce dat z pam\u011bti j\u00e1dra \u010din\u00ed p\u0159ibli\u017en\u011b 3,5 kB za sekundu.

\r\n \"P\u0159ehr\u00e1t\r\n
<\/div>\r\n <\/div><\/center> <\/p>\n

Metoda BHI p\u0159edstavuje roz\u0161\u00ed\u0159enou variantu \u00fatoku Spectre-v2, ve kter\u00e9 se pro obch\u00e1zen\u00ed p\u0159idan\u00e9 ochrany (Intel eIBRS a Arm CSV2) a organizaci \u00faniku dat pou\u017e\u00edv\u00e1 substituce hodnot v z\u00e1sobn\u00edku s glob\u00e1ln\u00ed histori\u00ed p\u0159echod\u016f (Branch History Buffer), pou\u017e\u00edvan\u00e9m v CPU pro zv\u00fd\u0161en\u00ed p\u0159esnosti predikce v\u011btven\u00ed d\u00edky zohledn\u011bn\u00ed historie minul\u00fdch p\u0159echod\u016f. B\u011bhem \u00fatoku prost\u0159ednictv\u00edm manipulac\u00ed s histori\u00ed p\u0159echod\u016f vznikaj\u00ed podm\u00ednky pro nespr\u00e1vn\u00e9 predikce p\u0159echodu a spekulativn\u00ed prov\u00e1d\u011bn\u00ed pot\u0159ebn\u00fdch instrukc\u00ed, jejich\u017e v\u00fdsledek se ukl\u00e1d\u00e1 do cache. <\/p>\n

Rozd\u00edly od \u00fatoku Spectre-v2 spo\u010d\u00edvaj\u00ed v pou\u017eit\u00ed bufferu s histori\u00ed p\u0159echod\u016f (Branch History Buffer) m\u00edsto bufferu predikce v\u011btven\u00ed (Branch Target Buffer). Aby \u00fato\u010dn\u00edk mohl z\u00edskat data z pam\u011bti, mus\u00ed vytvo\u0159it podm\u00ednky, za kter\u00fdch bude p\u0159i prov\u00e1d\u011bn\u00ed spekulativn\u00ed operace adresa p\u0159evzata z oblasti, kterou je t\u0159eba ur\u010dit. Po proveden\u00ed spekulativn\u00edho nep\u0159\u00edm\u00e9ho p\u0159echodu z\u016fst\u00e1v\u00e1 p\u0159e\u010dten\u00e1 adresa p\u0159echodu v cache, po jej\u00edm\u017e vyta\u017een\u00ed m\u016f\u017ee b\u00fdt pou\u017eita jedna z metod ur\u010dov\u00e1n\u00ed obsahu cache na z\u00e1klad\u011b anal\u00fdzy zm\u011bny doby p\u0159\u00edstupu k ulo\u017een\u00fdm a neulo\u017een\u00fdm dat\u016fm. <\/p>\n

Proti \u00fatoku Native BHI nechr\u00e1n\u00ed pou\u017eit\u00ed instrukc\u00ed Intel IBT (Indirect Branch Tracking) a implementovan\u00fd v j\u00e1d\u0159e syst\u00e9mu Linux hybridn\u00ed mechanismus ochrany toku prov\u00e1d\u011bn\u00ed p\u0159\u00edkaz\u016f FineIBT, kter\u00fd kombinuje pou\u017eit\u00ed hardwarov\u00fdch instrukc\u00ed IBT a softwarov\u00e9 ochrany kCFI (kernel Control Flow Integrity) pro blokov\u00e1n\u00ed poru\u0161en\u00ed norm\u00e1ln\u00edho po\u0159ad\u00ed prov\u00e1d\u011bn\u00ed (control flow). FineIBT povoluje prov\u00e1d\u011bn\u00ed prost\u0159ednictv\u00edm nep\u0159\u00edm\u00e9ho p\u0159echodu pouze v p\u0159\u00edpad\u011b p\u0159echodu na instrukci ENDBR, kter\u00e1 se umis\u0165uje na za\u010d\u00e1tek funkce. D\u00e1le (podobn\u011b jako mechanismus kCFI) se prov\u00e1d\u00ed kontrola hash\u016f, kter\u00e1 zaru\u010duje nem\u011bnnost ukazatel\u016f. <\/p>\n

Pro ochranu proti nov\u00e9mu variantu \u00fatoku bylo do j\u00e1dra Linux p\u0159id\u00e1no zm\u011bna s implementac\u00ed dal\u0161\u00edho re\u017eimu ochrany, kter\u00e1 pou\u017e\u00edv\u00e1 navr\u017een\u00e9 spole\u010dnosti Intel hardwarov\u00e9 prost\u0159edky ochrany (BHI_DIS_S) nebo alternativn\u00ed softwarovou ochranu, realizovanou pro ochranu hypervizora. KVM<\/a>. V\u00fdvoj\u00e1\u0159i hypervizoru Xen tak\u00e9 vydali opravu, kter\u00e1 je zalo\u017een\u00e1 na pou\u017eit\u00ed re\u017eimu BHI_DIS_S, omezuj\u00edc\u00edho predikce na z\u00e1klad\u011b historie p\u0159echod\u016f. Podpora BHI_DIS_S je dostupn\u00e1 v procesorech po\u010d\u00ednaje Intel Alder Lake, stejn\u011b jako v serverov\u00fdch CPU po\u010d\u00ednaje Intel Sapphire Rapids. K dispozici je tak\u00e9 softwarov\u00fd re\u017eim ochrany, zalo\u017een\u00fd na pou\u017eit\u00ed sekvenc\u00ed pro vymaz\u00e1n\u00ed bufferu historie p\u0159echod\u016f, av\u0161ak vede k v\u00fdrazn\u011bj\u0161\u00edmu poklesu v\u00fdkonu.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0413\u0440\u0443\u043f\u043f\u0430 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439 \u0438\u0437 \u0410\u043c\u0441\u0442\u0435\u0440\u0434\u0430\u043c\u0441\u043a\u043e\u0433\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u043d\u043e\u0432\u044b\u0439 \u043c\u0435\u0442\u043e\u0434 \u0430\u0442\u0430\u043a\u0438 «Native BHI» (CVE-2024-2201), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0439 \u043d\u0430 \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u0445 \u0441 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u0430\u043c\u0438 Intel \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0438\u0442\u044c \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u043f\u0430\u043c\u044f\u0442\u0438 \u044f\u0434\u0440\u0430 Linux \u043f\u0440\u0438 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\u0434\u0440\u0443\u0433\u0438\u0445 \u0433\u043e\u0441\u0442\u0435\u0432\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c. \u041c\u0435\u0442\u043e\u0434 Native BHI \u043f\u0440\u0435\u0434\u043b\u0430\u0433\u0430\u0435\u0442 \u0438\u043d\u0443\u044e […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":114956,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-114955","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\udd47Nov\u00fd variant \u00fatoku BHI na CPU Intel, kter\u00fd umo\u017e\u0148uje obej\u00edt ochranu v j\u00e1d\u0159e Linux | ProHoster","description":"Skupina v\u00fdzkumn\u00edk\u016f z Amsterodamsk\u00e9 svobodn\u00e9 univerzity odhalila novou metodu \u00fatoku \"Native BHI\" (CVE-2024-2201), kter\u00e1 umo\u017e\u0148uje na syst\u00e9mech s procesory Intel ur\u010dit obsah pam\u011bti j\u00e1dra Linux.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/novyj-variant-ataki-bhi-na-cpu-intel-pozvolyayushhij-obojti-zashhitu-v-yadre-linux","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","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\u041d\u043e\u0432\u044b\u0439 \u0432\u0430\u0440\u0438\u0430\u043d\u0442 \u0430\u0442\u0430\u043a\u0438 BHI \u043d\u0430 CPU Intel, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0439 \u043e\u0431\u043e\u0439\u0442\u0438 \u0437\u0430\u0449\u0438\u0442\u0443 \u0432 \u044f\u0434\u0440\u0435 Linux | ProHoster","og:description":"\u0413\u0440\u0443\u043f\u043f\u0430 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439 \u0438\u0437 \u0410\u043c\u0441\u0442\u0435\u0440\u0434\u0430\u043c\u0441\u043a\u043e\u0433\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u043d\u043e\u0432\u044b\u0439 \u043c\u0435\u0442\u043e\u0434 \u0430\u0442\u0430\u043a\u0438 "Native BHI" (CVE-2024-2201), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0439 \u043d\u0430 \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u0445 \u0441 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u0430\u043c\u0438 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\u043f\u0440\u0438.","og:url":"https:\/\/prohoster.info\/cs\/blog\/news\/novyj-variant-ataki-bhi-na-cpu-intel-pozvolyayushhij-obojti-zashhitu-v-yadre-linux","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":"2024-04-09T19:31:00+00:00","article:modified_time":"2024-04-09T19:31:00+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"114955","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":"2026-01-22 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