{"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\/hu\/blog\/news\/kriticheskaya-uyazvimost-v-realizaczii-funkczii-memcpy-dlya-armv7-iz-sostava-glibc","title":{"rendered":"Kritikus sebezhet\u0151s\u00e9g a Glibc r\u00e9szek\u00e9nt megval\u00f3s\u00edtott memcpy funkci\u00f3ban ARMv7-re","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

A biztons\u00e1gi kutat\u00f3k a Cisco c\u00e9gt\u0151l felfedt\u00e9k<\/a><\/noindex> a r\u00e9szleteket sebezhet\u0151s\u00e9gek<\/a><\/noindex> (CVE-2020-6096<\/a><\/noindex>) a Glibc memcpy() f\u00fcggv\u00e9ny\u00e9nek megval\u00f3s\u00edt\u00e1s\u00e1ban a 32 bites ARMv7 platformon. A probl\u00e9ma a m\u00e9rethat\u00e1roz\u00e1s sor\u00e1n a negat\u00edv \u00e9rt\u00e9kek helytelen kezel\u00e9s\u00e9b\u0151l ad\u00f3dik, amely a 32 bites eg\u00e9sz sz\u00e1mokkal val\u00f3 manipul\u00e1ci\u00f3t v\u00e9gz\u0151 assembler-optimaliz\u00e1l\u00e1sok miatt k\u00f6vetkezik be. A memcpy() h\u00edv\u00e1sa ARMv7 rendszereken negat\u00edv m\u00e9rettel helytelen \u00e9rt\u00e9kek \u00f6sszehasonl\u00edt\u00e1s\u00e1hoz \u00e9s a megadott puffer hat\u00e1rain k\u00edv\u00fcli ter\u00fcletekre val\u00f3 \u00edr\u00e1shoz vezet.<\/p>\n

A s\u00e9r\u00fcl\u00e9kenys\u00e9g kihaszn\u00e1lhat\u00f3 k\u00f3d v\u00e9grehajt\u00e1s\u00e1ra olyan helyzetekben, amikor a t\u00e1mad\u00f3 negat\u00edv \u00e9rt\u00e9k\u0171 v\u00e1ltoz\u00f3t tud l\u00e9trehozni, amely a m\u00e1solt adatok m\u00e9ret\u00e9t k\u00e9pviseli (p\u00e9ld\u00e1ul negat\u00edv \u00e9rt\u00e9ket lehet kapni 2 GB-n\u00e1l nagyobb adatmennyis\u00e9g \u00e1tvitele sor\u00e1n, de a puffer t\u00fall\u00e9p\u00e9s\u00e9hez legal\u00e1bb 4 GB-ot kell \u00e1tadni). A memcpy() f\u00fcggv\u00e9nyt sz\u00e9les k\u00f6rben haszn\u00e1lj\u00e1k alkalmaz\u00e1sokban, \u00e9s az ARMv7 processzorok elterjedtek aut\u00f3s rendszerekben, mobil, ipari, fogyaszt\u00f3i, kommunik\u00e1ci\u00f3s \u00e9s be\u00e1gyazott eszk\u00f6z\u00f6kben, amelyek potenci\u00e1lisan c\u00e9lpontokk\u00e1 v\u00e1lhatnak Bluetooth, HD Radio\/DAB, USB, CAN bus, Wi-Fi \u00e9s m\u00e1s k\u00fcls\u0151 adatforr\u00e1sokb\u00f3l sz\u00e1rmaz\u00f3 t\u00e1mad\u00e1sokkal (p\u00e9ld\u00e1ul t\u00e1madhat\u00f3ak az interneten el\u00e9rhet\u0151 szolg\u00e1ltat\u00e1sok \u00e9s alkalmaz\u00e1sok, amelyek korl\u00e1toz\u00e1s n\u00e9lk\u00fcli bemenetet fogadnak).<\/p>\n

P\u00e9ldak\u00e9nt bemutat\u00e1sra ker\u00fcl egy m\u0171k\u00f6d\u0151 exploit elk\u00e9sz\u00edt\u00e9se, amely t\u00e1mad\u00e1st ind\u00edt az aut\u00f3s inform\u00e1ci\u00f3s rendszerekbe be\u00e9p\u00edtett http-szerver ellen, amely el\u00e9rhet\u0151 az aut\u00f3 Wi-Fi h\u00e1l\u00f3zat\u00e1n. Az idegen t\u00e1mad\u00f3 kihaszn\u00e1lhatja a memcpy s\u00e9r\u00fcl\u00e9kenys\u00e9g\u00e9t a szerveren kereszt\u00fcl, ha nagyon nagy m\u00e9ret\u0171 GET-k\u00e9r\u00e9st k\u00fcld, \u00e9s root-hozz\u00e1f\u00e9r\u00e9st szerez a rendszerhez.<\/p>\n

\"Kritikus<\/a><\/noindex><\/center><\/p>\n

A 32 bites x86 rendszereken a probl\u00e9ma nem jelentkezik, mivel a memcpy ezen architekt\u00far\u00e1ra vonatkoz\u00f3 megval\u00f3s\u00edt\u00e1sa helyesen \u00e9rtelmezi a m\u00e9ret v\u00e1ltoz\u00f3t unsigned integer (size_t) t\u00edpus\u00fak\u00e9nt (a letartott assembler-alap\u00fa a megval\u00f3s\u00edt\u00e1sr\u00f3l<\/a><\/noindex> ARMv7 eset\u00e9n a size_t helyett signed integer-k\u00e9nt dolgozz\u00e1k fel). A jav\u00edt\u00e1s jelenleg el\u00e9rhet\u0151 egy patch form\u00e1j\u00e1ban<\/a><\/noindex>, amely beker\u00fcl a m\u00e1jusi Glibc 2.32 friss\u00edt\u00e9sbe.
\nA jav\u00edt\u00e1s az assembler utas\u00edt\u00e1sok olyan haszn\u00e1lat\u00e1nak cser\u00e9j\u00e9t jelenti, amelyek signed oper\u00e1torokkal dolgoznak (bge \u00e9s blt), unsigned megfelel\u0151ikre (blo \u00e9s bhs). <\/p>\n

A probl\u00e9ma jelenleg m\u00e9g nem ker\u00fclt orvosl\u00e1sra a Debian 9 \u00e9s 10<\/a><\/noindex> (Debian 8-ban nem jelentkezik) Fedora<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, OpenEmbedded, Tizen (glibc-t haszn\u00e1l). RHEL<\/a><\/noindex> \u00e9s SUSE<\/a><\/noindex> a probl\u00e9ma nem \u00e9rinti, mivel nem t\u00e1mogatj\u00e1k a 32 bites ARMv7 rendszereket. Az Android nem \u00e9rintett a sebezhet\u0151s\u00e9gben, mert saj\u00e1t libc (Bionic) megval\u00f3s\u00edt\u00e1st haszn\u00e1l. A OpenWRT<\/a><\/noindex> alap\u00e9rtelmez\u00e9s szerint a legt\u00f6bb \u00f6ssze\u00e1ll\u00edt\u00e1sban Muslt haszn\u00e1l, de el\u00e9rhet\u0151 glibc is a t\u00e1rol\u00f3ban.<\/p>\n

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

Forr\u00e1s: 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 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\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\udd47Kritikus sebezhet\u0151s\u00e9g a memcpy funkci\u00f3 ARMv7 megval\u00f3s\u00edt\u00e1s\u00e1ban a Glibc keretein bel\u00fcl | ProHoster","description":"A Cisco biztons\u00e1gi kutat\u00f3i felfedt\u00e9k a 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