{"id":92097,"date":"2020-08-22T19:42:16","date_gmt":"2020-08-22T17:42:16","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-chrony"},"modified":"2020-08-22T19:42:16","modified_gmt":"2020-08-22T17:42:16","slug":"uyazvimost-v-chrony","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-chrony","title":{"rendered":"Zranitelnost v chrony","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V chrony<\/a><\/noindex>, implementace protokolu NTP pou\u017e\u00edvan\u00e9ho pro synchronizaci p\u0159esn\u00e9ho \u010dasu v r\u016fzn\u00fdch distribuc\u00edch Linuxu, byla odhalena<\/a><\/noindex> zranitelnost (CVE-2020-14367<\/a><\/noindex>), kter\u00e1 umo\u017e\u0148uje p\u0159epsat jak\u00fdkoli soubor v syst\u00e9mu s p\u0159\u00edstupem k m\u00edstn\u00edmu neprivilegovan\u00e9mu u\u017eivateli chrony. Zranitelnost m\u016f\u017ee b\u00fdt zneu\u017eita pouze prost\u0159ednictv\u00edm u\u017eivatele chrony, co\u017e sni\u017euje jej\u00ed nebezpe\u010dnost. Nicm\u00e9n\u011b, probl\u00e9m ohro\u017euje \u00farove\u0148 izolace v chrony a m\u016f\u017ee b\u00fdt vyu\u017eit v p\u0159\u00edpad\u011b odhalen\u00ed jin\u00e9 zranitelnosti v k\u00f3du, kter\u00fd se vykon\u00e1v\u00e1 po sn\u00ed\u017een\u00ed privilegi\u00ed.<\/p>\n

Zranitelnost je zp\u016fsobena nezabezpe\u010den\u00fdm vytv\u00e1\u0159en\u00edm pid souboru, kter\u00fd byl vytvo\u0159en v obdob\u00ed, kdy chrony je\u0161t\u011b nesn\u00ed\u017eil privilegium a b\u011b\u017e\u00ed s pr\u00e1vy root. Katalog \/run\/chrony, do kter\u00e9ho je zapisov\u00e1n pid soubor, byl vytvo\u0159en s pr\u00e1vy 0750 prost\u0159ednictv\u00edm systemd-tmpfiles nebo p\u0159i spu\u0161t\u011bn\u00ed chronyd v\u00e1zan\u00e9ho na u\u017eivatele a skupinu \u201echrony\u201c. T\u00edm p\u00e1dem, pokud m\u00e1 u\u017eivatel chrony p\u0159\u00edstup, je mo\u017en\u00e9 nahradit pid soubor \/run\/chrony\/chronyd.pid symbolick\u00fdm odkazem. Symbolick\u00fd odkaz m\u016f\u017ee sm\u011b\u0159ovat na jak\u00fdkoli syst\u00e9mov\u00fd soubor, kter\u00fd bude p\u0159eps\u00e1n v okam\u017eiku spu\u0161t\u011bn\u00ed chronyd.<\/p>\n

root# systemctl stop chronyd.service
\n root# sudo -u chrony \/bin\/bash<\/p>\n

chrony$ cd \/run\/chrony
\n chrony$ ln -s \/etc\/shadow chronyd.pid
\n chrony$ exit<\/p>\n

root# \/usr\/sbin\/chronyd -n
\n ^C
\n # \u0432\u043c\u0435\u0441\u0442\u043e \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0433\u043e \/etc\/shadow \u0431\u0443\u0434\u0435\u0442 \u0441\u043e\u0445\u0440\u0430\u043d\u0451\u043d \u0438\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u0430 chronyd
\n root# cat \/etc\/shadow
\n 15287<\/p>\n

Zranitelnost odstran\u011bna<\/a><\/noindex> v vyd\u00e1n\u00ed chrony 3.5.1<\/a><\/noindex>. Aktualizace bal\u00ed\u010dk\u016f s opravou zranitelnosti jsou k dispozici pro Fedora<\/a><\/noindex>. P\u0159i p\u0159\u00edprav\u011b aktualizace pro RHEL<\/a><\/noindex>, Debian<\/a><\/noindex> a Ubuntu<\/a><\/noindex>.<\/p>\n

SUSE a openSUSE nen\u00ed dan\u00fd probl\u00e9m vystaven\u00fd<\/a><\/noindex>, proto\u017ee symbolick\u00fd odkaz pro chrony je vytv\u00e1\u0159en p\u0159\u00edmo v adres\u00e1\u0159i \/run, bez pou\u017eit\u00ed dal\u0161\u00edch podadres\u00e1\u0159\u016f. <\/p>\n

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

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

\u0412 chrony, \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 NTP, \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u0435\u043c\u043e\u0439 \u0434\u043b\u044f \u0441\u0438\u043d\u0445\u0440\u043e\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0442\u043e\u0447\u043d\u043e\u0433\u043e \u0432\u0440\u0435\u043c\u0435\u043d\u0438 \u0432 \u0440\u0430\u0437\u043b\u0438\u0447\u043d\u044b\u0445 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 Linux, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2020-14367), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043f\u0435\u0440\u0435\u0437\u0430\u043f\u0438\u0441\u0430\u0442\u044c \u043b\u044e\u0431\u043e\u0439 \u0444\u0430\u0439\u043b \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435, \u0438\u043c\u0435\u044f \u0434\u043e\u0441\u0442\u0443\u043f \u043a \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \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 chrony. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043c\u043e\u0436\u0435\u0442 \u0431\u044b\u0442\u044c \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0430 \u0442\u043e\u043b\u044c\u043a\u043e \u0447\u0435\u0440\u0435\u0437 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044f chrony, \u0447\u0442\u043e \u0441\u043d\u0438\u0436\u0430\u0435\u0442 \u0435\u0451 \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u044c. \u0422\u0435\u043c \u043d\u0435 \u043c\u0435\u043d\u0435\u0435, \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043a\u043e\u043c\u043f\u0440\u043e\u043c\u0435\u0442\u0438\u0440\u0443\u0435\u0442 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u0438\u0437\u043e\u043b\u044f\u0446\u0438\u0438 \u0432 chrony \u0438 \u043c\u043e\u0436\u0435\u0442 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c\u0441\u044f \u0432 […]<\/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-92097","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 chrony | ProHoster","description":"V chrony, implementaci protokolu NTP pou\u017e\u00edvan\u00e9ho pro synchronizaci p\u0159esn\u00e9ho \u010dasu v r\u016fzn\u00fdch distribuc\u00edch 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