{"id":76196,"date":"2020-03-31T19:42:05","date_gmt":"2020-03-31T17:42:05","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf"},"modified":"2020-03-31T19:42:05","modified_gmt":"2020-03-31T17:42:05","slug":"uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","title":{"rendered":"Linux kernel sebezhet\u0151s\u00e9g, amely lehet\u0151v\u00e9 teszi a privil\u00e9giumok emel\u00e9s\u00e9t BPF-en kereszt\u00fcl.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Megjelentek<\/a><\/noindex> sebezeti inform\u00e1ci\u00f3k (CVE-2020-8835<\/a><\/noindex>) a Linux kernelben, amelyet egy versenyen haszn\u00e1ltak Pwn2Own 2020<\/a><\/noindex> az Ubuntu felt\u00f6r\u00e9s\u00e9nek bemutat\u00f3j\u00e1n. Az elj\u00e1r\u00e1s lehet\u0151v\u00e9 tette, hogy egy norm\u00e1l felhaszn\u00e1l\u00f3 root jogosults\u00e1ghoz jusson. M\u0171k\u00f6d\u0151 exploit l\u00e9tezik, de m\u00e9g nem ker\u00fclt publik\u00e1l\u00e1sra. A sebezhet\u0151s\u00e9g az eBPF alrendszerben tal\u00e1lhat\u00f3, amely lehet\u0151v\u00e9 teszi a keretrendszerek nyomk\u00f6vet\u00e9s\u00e9re, teljes\u00edtm\u00e9nyelemz\u00e9s\u00e9re \u00e9s forgalomir\u00e1ny\u00edt\u00e1sra vonatkoz\u00f3 kezel\u0151k v\u00e9grehajt\u00e1s\u00e1t a kernelben egy k\u00fcl\u00f6n virtu\u00e1lis g\u00e9pben JIT-tel.<\/p>\n

A probl\u00e9ma a __reg_bound_offset32() f\u00fcggv\u00e9ny hib\u00e1j\u00e1b\u00f3l ered, amelyet a BPF bytecode 32 bites m\u0171veleteinek ellen\u0151rz\u00e9s\u00e9re haszn\u00e1lnak. A regiszter hat\u00e1rok hib\u00e1s kisz\u00e1m\u00edt\u00e1sa miatt, speci\u00e1lisan elk\u00e9sz\u00edtett BPF alkalmaz\u00e1sok feldolgoz\u00e1sa sor\u00e1n olyan \u00e1llapotok l\u00e9ptek fel, amelyek a kernel mem\u00f3ri\u00e1j\u00e1ban l\u00e9v\u0151 kiosztott pufferb\u0151l val\u00f3 olvas\u00e1sra \u00e9s \u00edr\u00e1sra tettek lehet\u0151s\u00e9get. A probl\u00e9ma a 5.5 kernelben jelent meg, \u00e9s k\u00e9s\u0151bb a jav\u00edt\u00e1sok visszaker\u00fcl\u00e9se sor\u00e1n a 5.4 kernelbe is \u00e1tvitt\u00e9k, valamint a 5.3 kernel csomagba<\/a><\/noindex>, amely Ubuntu Linuxban el\u00e9rhet\u0151.<\/p>\n

A sebezhet\u0151s\u00e9g blokkol\u00e1s\u00e1hoz aj\u00e1nlott visszag\u00f6rgetni<\/a><\/noindex> a probl\u00e9m\u00e1s jav\u00edt\u00e1st vagy megakad\u00e1lyozni a BPF alkalmaz\u00e1sok norm\u00e1l felhaszn\u00e1l\u00f3k \u00e1ltali futtat\u00e1s\u00e1t a sysctl kernel.unprivileged_bpf_disabled 1 \u00e9rt\u00e9kre \u00e1ll\u00edt\u00e1s\u00e1val. A jav\u00edt\u00e1s \u00e1llapota a disztrib\u00faci\u00f3kban: Ubuntu<\/a><\/noindex>, Debian<\/a><\/noindex>, Arch<\/a><\/noindex>, Fedora<\/a><\/noindex> \u00e9s SUSE<\/a><\/noindex> (a kernelbe RHEL<\/a><\/noindex> a probl\u00e9m\u00e1s v\u00e1ltoztat\u00e1s nem ker\u00fclt \u00e1t)<\/p>\n

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

Forr\u00e1s: opennet.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e\u0431 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2020-8835) \u0432 \u044f\u0434\u0440\u0435 Linux, \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u0431\u044b\u043b\u0430 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0430 \u0432 \u0441\u043e\u0440\u0435\u0432\u043d\u043e\u0432\u0430\u043d\u0438\u0438 Pwn2Own 2020 \u043f\u0440\u0438 \u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0430\u0446\u0438\u0438 \u0432\u0437\u043b\u043e\u043c\u0430 Ubuntu. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u043b\u0430 \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\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\u0430\u0432\u0430 root. \u0420\u0430\u0431\u043e\u0447\u0438\u0439 \u044d\u043a\u0441\u043f\u043b\u043e\u0438\u0442 \u0441\u0443\u0449\u0435\u0441\u0442\u0432\u0443\u0435\u0442, \u043d\u043e \u043f\u043e\u043a\u0430 \u043d\u0435 \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u0440\u0438\u0441\u0443\u0442\u0441\u0442\u0432\u0443\u0435\u0442 \u0432 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 eBPF, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0437\u0430\u043f\u0443\u0441\u043a\u0430\u0442\u044c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u0438 \u0434\u043b\u044f \u0442\u0440\u0430\u0441\u0441\u0438\u0440\u043e\u0432\u043a\u0438, \u0430\u043d\u0430\u043b\u0438\u0437\u0430 \u0440\u0430\u0431\u043e\u0442\u044b \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c \u0438 \u0443\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0438\u044f \u0442\u0440\u0430\u0444\u0438\u043a\u043e\u043c, \u0432\u044b\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u044b\u0435 \u0432\u043d\u0443\u0442\u0440\u0438 \u044f\u0434\u0440\u0430 \u0432 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e\u0439 \u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u043e\u0439 […]<\/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-76196","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\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\udd47Sebezhet\u0151s\u00e9g a Linux kernelben, amely lehet\u0151v\u00e9 teszi a jogosults\u00e1gok 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