{"id":100767,"date":"2021-07-15T16:22:45","date_gmt":"2021-07-15T14:22:45","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-podsisteme-yadra-linux-netfilter"},"modified":"2021-07-15T16:22:45","modified_gmt":"2021-07-15T14:22:45","slug":"uyazvimost-v-podsisteme-yadra-linux-netfilter","status":"publish","type":"post","link":"https:\/\/prohoster.info\/et\/blog\/news\/uyazvimost-v-podsisteme-yadra-linux-netfilter","title":{"rendered":"Haavatavus Linuxi Netfilteri alams\u00fcsteemis","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Netfilteris, Linuxi tuumaal v\u00f5imalusi pakkuda ja muuta v\u00f5rgupakette, on avastatud haavatavus (CVE-2021-22555), mis v\u00f5imaldab kohalikel kasutajatel saada s\u00fcsteemis root-privileege, sealhulgas t\u00f6\u00f6tades isoleeritud konteineris. Testimiseks on valmistatud t\u00f6\u00f6protot\u00fc\u00fcp eksploidist, mis \u00fcletab KASLR, SMAP ja SMEP kaitsemehhanisme. Haavatavuse avastaja sai Google'ilt 20 000 dollari suuruse tasu Kubernetes'i konteinerite isoleerimise \u00fcletamise meetodi avastamise eest kCTF klastris. <\/p>\n

Probleem ilmneb alates tuumast 2.6.19, mis ilmus 15 aastat tagasi, ja seda p\u00f5hjustab viga IPT_SO_SET_REPLACE ja IP6T_SO_SET_REPLACE k\u00e4itlejates, mis viib m\u00e4lupuhvri \u00fclevooluni, kui spetsiaalselt vormindatud parameetreid saadetakse setsockopt'i kutsumise kaudu \u00fchilduvusre\u017eiimis. Tavalistes tingimustes saab kutsumist compat_setsockopt() teha ainult root-kasutaja, kuid r\u00fcnnaku teostamiseks vajalikud volitused v\u00f5ivad samuti olla saadud privileegideta kasutaja poolt s\u00fcsteemides, kus on lubatud kasutajanimede ruumide (user namespaces) tugi. <\/p>\n

Kasutaja saab luua konteineri eraldi root-kasutajaga ja seda kasutada haavatavuse kuritarvitamiseks. N\u00e4iteks on \u201ekasutaja nimed\u201c vaikimisi aktiveeritud Ubuntu ja Fedora, kuid nad ei ole aktiveeritud Debianis ja RHELis. Haavatavuse parandamise plaastrit vastu v\u00f5etud Linuxi tuuma 13. aprillil. Paketihalduri uuendused on juba v\u00e4lja t\u00f6\u00f6tatud Debian, Arch Linuxi ja Fedora projektide poolt. Ubuntu, RHEL ja SUSE uuendused on valmimisj\u00e4rgus. <\/p>\n

Probleem ilmneb funktsioonis xt_compat_target_from_user() vale m\u00e4lu suuruse arvutamise t\u00f5ttu, kui salvestatakse tuuma struktuuris, muundades 32-bitise esitluse 64-bitiseks. Viga v\u00f5imaldab kirjutada neli nullbaitiga mistahes asukohta eraldatud puhverdest v\u00e4ljaspool, piirates nihke 0x4C. Antud v\u00f5imalus osutus piisavaks eksploiti loomiseks, mis v\u00f5imaldas saavutada root-\u00f5igusi \u2014 m_list->next ukse puhastamine msg_msg struktuuris l\u00f5i tingimused m\u00e4lust vabastamise j\u00e4rgselt andmete juurde p\u00e4\u00e4semiseks (kasutamata vaba m\u00e4lu), mida seej\u00e4rel kasutati aadresside saamiseks ja teiste struktuuride muutmiseks s\u00fcsteemik\u00f5ne msgsnd() manipuleerimise kaudu.
\n
Allikas: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 Netfilter, \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u044f\u0434\u0440\u0430 Linux, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c\u043e\u0439 \u0434\u043b\u044f \u0444\u0438\u043b\u044c\u0442\u0440\u0430\u0446\u0438\u0438 \u0438 \u043c\u043e\u0434\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u0441\u0435\u0442\u0435\u0432\u044b\u0445 \u043f\u0430\u043a\u0435\u0442\u043e\u0432, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-22555), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 root \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435, \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u043d\u0430\u0445\u043e\u0434\u044f\u0441\u044c \u0432 \u0438\u0437\u043e\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c \u043a\u043e\u043d\u0442\u0435\u0439\u043d\u0435\u0440\u0435. \u0414\u043b\u044f \u0442\u0435\u0441\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u043b\u0435\u043d \u0440\u0430\u0431\u043e\u0447\u0438\u0439 \u043f\u0440\u043e\u0442\u043e\u0442\u0438\u043f \u044d\u043a\u0441\u043f\u043b\u043e\u0438\u0442\u0430, \u043e\u0431\u0445\u043e\u0434\u044f\u0449\u0438\u0439 \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u044b \u0437\u0430\u0449\u0438\u0442\u044b KASLR, SMAP \u0438 SMEP. \u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c, \u0432\u044b\u044f\u0432\u0438\u0432\u0448\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c, \u043f\u043e\u043b\u0443\u0447\u0438\u043b \u043e\u0442 Google \u0432\u043e\u0437\u043d\u0430\u0433\u0440\u0430\u0436\u0434\u0435\u043d\u0438\u0435, \u0440\u0430\u0437\u043c\u0435\u0440\u043e\u043c 20 \u0442\u044b\u0441\u044f\u0447 \u0434\u043e\u043b\u043b\u0430\u0440\u043e\u0432, \u0437\u0430 […]<\/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-100767","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\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\udd47Haavatavus Linuxi tuuma alams\u00fcsteemis Netfilter | ProHoster","description":"Netfilteris, Linuxi tuuma alams\u00fcsteemis, mis on m\u00f5eldud v\u00f5rgupakettide filtreerimiseks ja muutmiseks, on avastatud haavatavus (CVE-2021-22555), mis v\u00f5imaldab kohalikel kasutajatel saada s\u00fcsteemis root-privileegid, sealhulgas.","canonical_url":"https:\/\/prohoster.info\/et\/blog\/news\/uyazvimost-v-podsisteme-yadra-linux-netfilter","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"et_EE","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\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u044f\u0434\u0440\u0430 Linux Netfilter | ProHoster","og:description":"\u0412 Netfilter, \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u044f\u0434\u0440\u0430 Linux, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c\u043e\u0439 \u0434\u043b\u044f \u0444\u0438\u043b\u044c\u0442\u0440\u0430\u0446\u0438\u0438 \u0438 \u043c\u043e\u0434\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u0441\u0435\u0442\u0435\u0432\u044b\u0445 \u043f\u0430\u043a\u0435\u0442\u043e\u0432, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-22555), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 root \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435, \u0432 \u0442\u043e\u043c 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