{"id":38918,"date":"2019-10-31T22:26:45","date_gmt":"2019-10-31T19:26:45","guid":{"rendered":"https:\/\/prohoster.info\/blog\/uyazvimost-v-sudo-pozvolyayushhaya-povysit-privilegii-pri-ispolzovanii-spetsifichnyh-pravil\/"},"modified":"2019-10-31T22:26:45","modified_gmt":"2019-10-31T19:26:45","slug":"uyazvimost-v-sudo-pozvolyayushhaya-povysit-privilegii-pri-ispolzovanii-spetsifichnyh-pravil","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-sudo-pozvolyayushhaya-povysit-privilegii-pri-ispolzovanii-spetsifichnyh-pravil","title":{"rendered":"Zranitelnost v sudo, kter\u00e1 umo\u017e\u0148uje zv\u00fd\u0161it privilegium pomoc\u00ed specifick\u00fdch pravidel","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V n\u00e1stroji Sudo<\/a><\/noindex>, pou\u017e\u00edvan\u00e9 k organizaci prov\u00e1d\u011bn\u00ed p\u0159\u00edkaz\u016f jm\u00e9nem jin\u00fdch u\u017eivatel\u016f, byla odhalena<\/a><\/noindex> zranitelnost<\/a><\/noindex> (CVE-2019-14287<\/a><\/noindex>), kter\u00e1 umo\u017e\u0148uje prov\u00e1d\u011bt p\u0159\u00edkazy s pr\u00e1vy root, pokud jsou v nastaven\u00ed sudoers pravidla, v nich\u017e v \u010d\u00e1sti kontroly identifik\u00e1toru u\u017eivatele po povoluj\u00edc\u00edm kl\u00ed\u010dov\u00e9m slovu «ALL» uveden v\u00fdslovn\u00fd z\u00e1kaz spu\u0161t\u011bn\u00ed s pr\u00e1vy root («… (ALL, !root) …»). V konfigurac\u00edch podle v\u00fdchoz\u00edho nastaven\u00ed v distribuc\u00edch se zranitelnost neprojevuje. <\/p>\n

Pokud v sudoers existuj\u00ed povolen\u00e9, ale v praxi velmi vz\u00e1cn\u00e9 pravidla, kter\u00e1 umo\u017e\u0148uj\u00ed vykon\u00e1n\u00ed ur\u010dit\u00e9ho p\u0159\u00edkazu pod UID identifik\u00e1torem jak\u00e9hokoli u\u017eivatele krom\u011b root, m\u016f\u017ee \u00fato\u010dn\u00edk, kter\u00fd m\u00e1 opr\u00e1vn\u011bn\u00ed tento p\u0159\u00edkaz vykonat, obej\u00edt stanoven\u00e9 omezen\u00ed a vykonat p\u0159\u00edkaz s pr\u00e1vy root. Pro obejit\u00ed omezen\u00ed sta\u010d\u00ed pokusit se vykonat vyjmenovan\u00fd p\u0159\u00edkaz v nastaven\u00ed s UID «-1» nebo «4294967295», co\u017e povede k jeho vykon\u00e1n\u00ed s UID 0. <\/p>\n

Nap\u0159\u00edklad pokud v nastaven\u00ed existuje pravidlo, kter\u00e9 povoluje libovoln\u00e9mu u\u017eivateli vykon\u00e1n\u00ed programu \/usr\/bin\/id pod libovoln\u00fdm UID:<\/p>\n

myhost ALL = (ALL, !root) \/usr\/bin\/id<\/p>\n

nebo varianta, kter\u00e1 povoluje vykon\u00e1n\u00ed pouze konkr\u00e9tn\u00edmu u\u017eivateli bob:<\/p>\n

myhost bob = (ALL, !root) \/usr\/bin\/id<\/p>\n

U\u017eivatel m\u016f\u017ee prov\u00e9st «sudo -u ‘#-1’ id» a utilita \/usr\/bin\/id bude spu\u0161t\u011bna s pr\u00e1vy root, p\u0159esto\u017ee je v nastaven\u00ed v\u00fdslovn\u00fd z\u00e1kaz. Probl\u00e9m je zp\u016fsoben opomenut\u00edm speci\u00e1ln\u00edch hodnot «-1» nebo «4294967295», kter\u00e9 nevedou ke zm\u011bn\u011b UID, ale proto\u017ee samotn\u00e9 sudo ji\u017e b\u011b\u017e\u00ed pod root, bez zm\u011bny UID se tak\u00e9 c\u00edlov\u00fd p\u0159\u00edkaz spou\u0161t\u00ed s pr\u00e1vy root. <\/p>\n

V distribuc\u00edch SUSE a openSUSE bez uveden\u00ed v pravidle «NOPASSWD» se zranitelnost nevyu\u017eiteln\u00e1<\/a><\/noindex>, jeliko\u017e je v sudoers ve v\u00fdchoz\u00edm nastaven\u00ed zapnut re\u017eim «Defaults targetpw», p\u0159i kter\u00e9m se prov\u00e1d\u00ed kontrola UID podle datab\u00e1ze hesel s v\u00fdstupem po\u017eadavku na zad\u00e1n\u00ed hesla c\u00edlov\u00e9ho u\u017eivatele. Pro podobn\u00e9 syst\u00e9my m\u016f\u017ee b\u00fdt \u00fatok proveden pouze p\u0159i ur\u010den\u00fdch pravidlech n\u00e1sleduj\u00edc\u00edho typu:<\/p>\n

myhost ALL = (ALL, !root) NOPASSWD: \/usr\/bin\/id<\/p>\n

Probl\u00e9m byl vy\u0159e\u0161en ve verzi Sudo 1.8.28<\/a><\/noindex>. Oprava je tak\u00e9 dostupn\u00e1 ve form\u011b patche<\/a><\/noindex>. V distribuc\u00edch je zranitelnost ji\u017e odstran\u011bna v Debian<\/a><\/noindex>, Arch Linux<\/a><\/noindex>, SUSE\/openSUSE<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, Gentoo<\/a><\/noindex> a FreeBSD<\/a><\/noindex>. K datu naps\u00e1n\u00ed zpr\u00e1vy probl\u00e9m z\u016fst\u00e1v\u00e1 neopraviteln\u00fd v RHEL<\/a><\/noindex> a Fedora<\/a><\/noindex>. Zranitelnost byla objevena bezpe\u010dnostn\u00edmi v\u00fdzkumn\u00edky z firmy Apple.<\/p>\n

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

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

\u0412 \u0443\u0442\u0438\u043b\u0438\u0442\u0435 Sudo, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u043c\u043e\u0439 \u0434\u043b\u044f \u043e\u0440\u0433\u0430\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043a\u043e\u043c\u0430\u043d\u0434 \u043e\u0442 \u0438\u043c\u0435\u043d\u0438 \u0434\u0440\u0443\u0433\u0438\u0445 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2019-14287), \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043a\u043e\u043c\u0430\u043d\u0434 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root, \u043f\u0440\u0438 \u043d\u0430\u043b\u0438\u0447\u0438\u0438 \u0432 \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0430\u0445 sudoers \u043f\u0440\u0430\u0432\u0438\u043b, \u0432 \u043a\u043e\u0442\u043e\u0440\u044b\u0445 \u0432 \u0441\u0435\u043a\u0446\u0438\u0438 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0438 \u0438\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u0430 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044f \u043f\u043e\u0441\u043b\u0435 \u0440\u0430\u0437\u0440\u0435\u0448\u0430\u044e\u0449\u0435\u0433\u043e \u043a\u043b\u044e\u0447\u0435\u0432\u043e\u0433\u043e \u0441\u043b\u043e\u0432\u0430 «ALL» \u0441\u043b\u0435\u0434\u0443\u0435\u0442 \u044f\u0432\u043d\u044b\u0439 \u0437\u0430\u043f\u0440\u0435\u0442 \u0437\u0430\u043f\u0443\u0441\u043a\u0430 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root («… (ALL, !root) …»). \u0412 \u043a\u043e\u043d\u0444\u0438\u0433\u0443\u0440\u0430\u0446\u0438\u044f\u0445 \u043f\u043e […]<\/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-38918","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\udd47Zranitelnost v sudo, kter\u00e1 umo\u017e\u0148uje zv\u00fd\u0161en\u00ed opr\u00e1vn\u011bn\u00ed p\u0159i pou\u017eit\u00ed specifick\u00fdch pravidel | ProHoster","description":"V utilit\u011b Sudo, kter\u00e1 se pou\u017e\u00edv\u00e1 k organizaci prov\u00e1d\u011bn\u00ed p\u0159\u00edkaz\u016f jm\u00e9nem jin\u00fdch u\u017eivatel\u016f,","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-sudo-pozvolyayushhaya-povysit-privilegii-pri-ispolzovanii-spetsifichnyh-pravil","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\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 sudo, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 \u043f\u0440\u0438 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