{"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\/cs\/blog\/news\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","title":{"rendered":"Kritick\u00e1 zranitelnost v implementaci funkce memcpy pro ARMv7 ze sou\u010d\u00e1sti Glibc","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Bezpe\u010dnostn\u00ed v\u00fdzkumn\u00edci ze spole\u010dnosti Cisco odhalili<\/a><\/noindex> detaily zranitelnosti<\/a><\/noindex> (CVE-2020-6096<\/a><\/noindex>) v implementaci funkce memcpy() poskytovan\u00e9 v Glibc pro 32bitovou platformu ARMv7. Probl\u00e9m je zp\u016fsoben nespr\u00e1vn\u00fdm zpracov\u00e1n\u00edm z\u00e1porn\u00fdch hodnot parametru, kter\u00fd ur\u010duje velikost kop\u00edrovan\u00e9 oblasti, v d\u016fsledku pou\u017eit\u00ed assemblerov\u00fdch optimalizac\u00ed manipuluj\u00edc\u00edch se znam\u00e9nkov\u00fdmi 32bitov\u00fdmi cel\u00fdmi \u010d\u00edsly. Vol\u00e1n\u00ed memcpy() na syst\u00e9mech ARMv7 s negativn\u00ed velikost\u00ed vede k nespr\u00e1vn\u00e9mu porovn\u00e1n\u00ed hodnot a z\u00e1pisu do oblast\u00ed mimo hranice ur\u010den\u00e9ho bufferu.<\/p>\n

Zranitelnost m\u016f\u017ee b\u00fdt vyu\u017eita k vykon\u00e1n\u00ed k\u00f3du v situaci, kdy \u00fato\u010dn\u00edk m\u016f\u017ee zp\u016fsobit generov\u00e1n\u00ed z\u00e1porn\u00e9 hodnoty prom\u011bnn\u00e9, p\u0159es kterou se p\u0159ed\u00e1v\u00e1 velikost kop\u00edrovan\u00fdch dat (nap\u0159\u00edklad dojde k z\u00e1porn\u00e9 hodnot\u011b p\u0159i p\u0159ed\u00e1n\u00ed v\u00edce ne\u017e 2 GB dat, ale b\u011bhem \u00fatoku je t\u0159eba p\u0159edat alespo\u0148 4 GB, aby se vy\u0161lo za hranice bufferu). Funkce memcpy() se aktivn\u011b pou\u017e\u00edv\u00e1 v aplikac\u00edch a procesory ARMv7 jsou b\u011b\u017en\u00e9 v automobilov\u00fdch syst\u00e9mech, mobiln\u00edch, pr\u016fmyslov\u00fdch, spot\u0159ebitelsk\u00fdch, komunika\u010dn\u00edch a vestav\u011bn\u00fdch za\u0159\u00edzen\u00edch, kter\u00e9 mohou potenci\u00e1ln\u011b b\u00fdt c\u00edlem \u00fatok\u016f pomoc\u00ed Bluetooth, HD Radio\/DAB, USB, CAN bus, Wi-Fi a dal\u0161\u00edch extern\u00edch datov\u00fdch zdroj\u016f (nap\u0159\u00edklad mohou b\u00fdt napadeny s\u00ed\u0165ov\u00e9 slu\u017eby a aplikace, kter\u00e9 p\u0159ij\u00edmaj\u00ed vstupy bez omezen\u00ed velikosti).<\/p>\n

Jako p\u0159\u00edklad je uvedeno vytvo\u0159en\u00ed funk\u010dn\u00edho exploit pro \u00fatok na vestav\u011bn\u00fd http server v automobilov\u00fdch informa\u010dn\u00edch syst\u00e9mech, kter\u00fd je dostupn\u00fd p\u0159es automobilovou Wi-Fi s\u00ed\u0165. Ciz\u00ed \u00fato\u010dn\u00edk m\u016f\u017ee zneu\u017e\u00edt zranitelnost v memcpy na tomto serveru t\u00edm, \u017ee po\u0161le velmi velk\u00fd GET po\u017eadavek a z\u00edsk\u00e1 root p\u0159\u00edstup k syst\u00e9mu.<\/p>\n

\"Kritick\u00e1<\/a><\/noindex><\/center><\/p>\n

Na 32bitov\u00fdch syst\u00e9mech x86 se probl\u00e9m neprojevuje, proto\u017ee implementace memcpy pro tuto architekturu spr\u00e1vn\u011b interpretuje prom\u011bnnou s velikost\u00ed jako bezznamkov\u00e9 cel\u00e9 \u010d\u00edslo typu size_t (v napsan\u00e9m assembleru prov\u00e1d\u011bn\u00ed<\/a><\/noindex> pro ARMv7 je m\u00edsto size_t zpracov\u00e1v\u00e1na jako znamkov\u00e9 cel\u00e9 \u010d\u00edslo). Oprava je zat\u00edm k dispozici jako patche<\/a><\/noindex>, kter\u00e1 bude sou\u010d\u00e1st\u00ed srpnov\u00e9 aktualizace Glibc 2.32.
\nOprava spo\u010d\u00edv\u00e1 v nahrazen\u00ed pou\u017eit\u00ed assemblerov\u00fdch instrukc\u00ed, kter\u00e9 pracuj\u00ed se znam\u00e9nkov\u00fdmi operandy (bge a blt), jejich bezznamkov\u00fdmi ekvivalentami (blo a bhs). <\/p>\n

Probl\u00e9m nebyl zat\u00edm odstran\u011bn v Debian 9 a 10<\/a><\/noindex> (v Debian 8 se neprojevuje), Fedora<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, OpenEmbedded, Tizen (pou\u017e\u00edv\u00e1 glibc). RHEL<\/a><\/noindex> a SUSE<\/a><\/noindex> probl\u00e9m se net\u00fdk\u00e1, proto\u017ee nepodporuj\u00ed 32-bitov\u00e9 syst\u00e9my ARMv7. Android nen\u00ed zraniteln\u00fd, proto\u017ee pou\u017e\u00edv\u00e1 vlastn\u00ed implementaci libc (Bionic). V OpenWRT<\/a><\/noindex> v\u011bt\u0161inou ve v\u011bt\u0161in\u011b sestaven\u00ed se pou\u017e\u00edv\u00e1 Musl, ale v repozit\u00e1\u0159i je k dispozici i glibc.<\/p>\n

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

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

\u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0438 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 Cisco \u0440\u0430\u0441\u043a\u0440\u044b\u043b\u0438 \u0434\u0435\u0442\u0430\u043b\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2020-6096) \u0432 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u0435\u0434\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u0439 \u0432 Glibc \u0444\u0443\u043d\u043a\u0446\u0438\u0438 memcpy() \u0434\u043b\u044f 32-\u0440\u0430\u0437\u0440\u044f\u0434\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b ARMv7. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0432\u044b\u0437\u0432\u0430\u043d\u0430 \u043d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u0439 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u043e\u0439 \u043e\u0442\u0440\u0438\u0446\u0430\u0442\u0435\u043b\u044c\u043d\u044b\u0445 \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0439 \u043f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u0430, \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u044f\u044e\u0449\u0435\u0433\u043e \u0440\u0430\u0437\u043c\u0435\u0440 \u043a\u043e\u043f\u0438\u0440\u0443\u0435\u043c\u043e\u0439 \u043e\u0431\u043b\u0430\u0441\u0442\u0438, \u0438\u0437-\u0437\u0430 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u0430\u0441\u0441\u0435\u043c\u0431\u043b\u0435\u0440\u043d\u044b\u0445 \u043e\u043f\u0442\u0438\u043c\u0438\u0437\u0430\u0446\u0438\u0439, \u043c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u0443\u044e\u0449\u0438\u0445 \u0437\u043d\u0430\u043a\u043e\u0432\u044b\u043c\u0438 32-\u0440\u0430\u0437\u0440\u044f\u0434\u043d\u044b\u043c\u0438 \u0446\u0435\u043b\u044b\u043c\u0438 \u0447\u0438\u0441\u043b\u0430\u043c\u0438. \u0412\u044b\u0437\u043e\u0432 memcpy() \u043d\u0430 \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u0445 ARMv7 \u0441 \u043e\u0442\u0440\u0438\u0446\u0430\u0442\u0435\u043b\u044c\u043d\u044b\u043c \u0440\u0430\u0437\u043c\u0435\u0440\u043e\u043c \u043f\u0440\u0438\u0432\u043e\u0434\u0438\u0442 \u043a \u043d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u043c\u0443 \u0441\u0440\u0430\u0432\u043d\u0435\u043d\u0438\u044e \u0437\u043d\u0430\u0447\u0435\u043d\u0438\u0439 \u0438 \u0437\u0430\u043f\u0438\u0441\u0438 […]<\/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\udd47Kritick\u00e1 zranitelnost v implementaci funkce memcpy pro ARMv7 v r\u00e1mci Glibc | ProHoster","description":"Bezpe\u010dnostn\u00ed v\u00fdzkumn\u00edci z firmy Cisco zve\u0159ejnili podrobnosti","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","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\u041a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u0444\u0443\u043d\u043a\u0446\u0438\u0438 memcpy \u0434\u043b\u044f ARMv7 \u0438\u0437 \u0441\u043e\u0441\u0442\u0430\u0432\u0430 Glibc | ProHoster","og:description":"\u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0438 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 Cisco \u0440\u0430\u0441\u043a\u0440\u044b\u043b\u0438 \u0434\u0435\u0442\u0430\u043b\u0438","og:url":"https:\/\/prohoster.info\/cs\/blog\/news\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","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":"2020-05-22T17:41:55+00:00","article:modified_time":"2020-05-22T17:41:55+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"82556","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":null,"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":null,"breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2021-02-28 15:35:23","updated":"2022-09-28 08:25:32","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/82556","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/comments?post=82556"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/82556\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media\/82557"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media?parent=82556"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/categories?post=82556"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/tags?post=82556"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}