{"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\/ro\/blog\/news\/uyazvimost-v-chrony","title":{"rendered":"Vulnerabilitate \u00een chrony","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\u00cen chrony<\/a><\/noindex>, implementarea protocolului NTP, folosit pentru sincronizarea timpului exact \u00een diverse distribu\u021bii Linux, a fost identificat\u0103<\/a><\/noindex> vulnerabilitate (CVE-2020-14367<\/a><\/noindex>), permi\u021b\u00e2nd scrierea oric\u0103rui fi\u0219ier din sistem, av\u00e2nd acces la un utilizator local f\u0103r\u0103 privilegii chrony. Vulnerabilitatea poate fi exploatat\u0103 doar prin intermediul utilizatorului chrony, ceea ce \u00eei reduce periculozitatea. Cu toate acestea, problema compromite nivelul de izolare \u00een chrony \u0219i poate fi folosit\u0103 \u00een cazul identific\u0103rii unei alte vulnerabilit\u0103\u021bi \u00een codul executat dup\u0103 resetarea privilegiilor.<\/p>\n

Vulnerabilitatea este cauzat\u0103 de crearea nesigur\u0103 a fi\u0219ierului pid, care era generat \u00een etapa \u00een care chrony nu \u00ee\u0219i resetase \u00eenc\u0103 privilegiile \u0219i ruleaz\u0103 cu drepturi de root. \u00cen acest timp, directorul \/run\/chrony, \u00een care este scris fi\u0219ierul pid, era creat cu drepturi 0750 prin systemd-tmpfiles sau \u00een timpul lans\u0103rii chronyd legat de utilizatorul \u0219i grupul \u201echrony\u201d. Astfel, \u00een cazul \u00een care exist\u0103 acces la utilizatorul chrony, exist\u0103 posibilitatea de a \u00eenlocui fi\u0219ierul pid \/run\/chrony\/chronyd.pid cu un link simbolic. Linkul simbolic poate indica c\u0103tre orice fi\u0219ier de sistem, care va fi suprascris \u00een momentul lans\u0103rii 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

Vulnerabilitatea remediat\u0103<\/a><\/noindex> \u00een versiunea chrony 3.5.1<\/a><\/noindex>. Actualiz\u0103rile pachetelor pentru remedierea vulnerabilit\u0103\u021bii sunt disponibile pentru Fedora<\/a><\/noindex>. \u00cen procesul de preg\u0103tire a actualiz\u0103rii pentru RHEL<\/a><\/noindex>, Debian<\/a><\/noindex> \u0219i Ubuntu<\/a><\/noindex>.<\/p>\n

SUSE \u0219i openSUSE problema vulnerabile<\/a><\/noindex>, deoarece linkul simbolic pentru chrony este creat direct \u00een directorul \/run, f\u0103r\u0103 utilizarea de subdirectoare suplimentare. <\/p>\n

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

Sursa: opennet.ro<\/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\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\udd47Vulnerabilitate \u00een chrony | ProHoster","description":"\u00cen chrony, implementarea protocolului NTP, folosit pentru sincronizarea timpului exact \u00een diverse distribu\u021bii 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