{"id":41582,"date":"2020-02-12T16:19:30","date_gmt":"2020-02-12T13:19:30","guid":{"rendered":"https:\/\/prohoster.info\/blog\/blog_prohoster\/uyazvimost-v-systemd-potenczialno-pozvolyayushhaya-povysit-svoi-privilegii"},"modified":"2020-02-12T16:19:30","modified_gmt":"2020-02-12T13:19:30","slug":"uyazvimost-v-systemd-potenczialno-pozvolyayushhaya-povysit-svoi-privilegii","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/uyazvimost-v-systemd-potenczialno-pozvolyayushhaya-povysit-svoi-privilegii","title":{"rendered":"A systemd-ben tal\u00e1lhat\u00f3 s\u00e9r\u00fcl\u00e9kenys\u00e9g, amely potenci\u00e1lisan lehet\u0151v\u00e9 teszi a jogosults\u00e1gok emel\u00e9s\u00e9t.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

A rendszerkezel\u0151ben, a systemd-ben identified<\/a><\/noindex> vulnerability (CVE-2020-1712<\/a><\/noindex>), amely potenci\u00e1lisan lehet\u0151v\u00e9 teszi a saj\u00e1t k\u00f3dunk futtat\u00e1s\u00e1t megn\u00f6velt jogosults\u00e1gokkal, ha kifejezetten form\u00e1zott k\u00e9r\u00e9st k\u00fcld\u00fcnk a DBus buszon. A probl\u00e9ma jav\u00edtva lett a tesztkiad\u00e1sban systemd 245-rc1<\/a><\/noindex> (a probl\u00e9m\u00e1t megold\u00f3 jav\u00edt\u00e1sok: 1<\/a><\/noindex>, 2<\/a><\/noindex>, 3<\/a><\/noindex>). A sebezhet\u0151s\u00e9g elh\u00e1r\u00edtva van a disztrib\u00faci\u00f3kban Ubuntu<\/a><\/noindex>, Fedora<\/a><\/noindex>, RHEL<\/a><\/noindex> (a RHEL 8-ban jelentkezik, de nem \u00e9rinti a RHEL 7-et), CentOS<\/a><\/noindex>, SUSE\/openSUSE<\/a><\/noindex> \u00e9s ALT Linux<\/a><\/noindex>, de a h\u00edr \u00edr\u00e1s\u00e1nak pillanat\u00e1ban m\u00e9g mindig nem jav\u00edtott\u00e1k Debian<\/a><\/noindex> \u00e9s Arch Linux<\/a><\/noindex>. <\/p>\n

A sebezhet\u0151s\u00e9get egy m\u00e1r felszabad\u00edtott mem\u00f3ria ter\u00fclethez val\u00f3 hozz\u00e1f\u00e9r\u00e9s (use-after-free) okozza, amely aszinkron k\u00e9r\u00e9sek Polkit-nek t\u00f6rt\u00e9n\u0151 feldolgoz\u00e1sa sor\u00e1n l\u00e9p fel a DBus \u00fczenetek kezel\u00e9se k\u00f6zben. N\u00e9h\u00e1ny DBus interf\u00e9sz gyors\u00edt\u00f3t\u00e1rat haszn\u00e1l az objektumok r\u00f6vid ideig t\u00f6rt\u00e9n\u0151 t\u00e1rol\u00e1s\u00e1ra, \u00e9s t\u00f6rli a gyors\u00edt\u00f3t\u00e1r elemeit, amint a DBus busz el\u00e9rhet\u0151v\u00e9 v\u00e1lik m\u00e1s k\u00e9r\u00e9sek feldolgoz\u00e1s\u00e1ra. Ha a DBus m\u00f3dszer kezel\u0151je bus_verify_polkit_async()-ot haszn\u00e1l, lehet, hogy v\u00e1rnia kell a Polkit-ban v\u00e9gzett m\u0171velet befejez\u00e9s\u00e9re. Amikor a Polkit k\u00e9sz, a kezel\u0151t \u00fajra h\u00edvj\u00e1k, \u00e9s az m\u00e1r kor\u00e1bban a mem\u00f3ri\u00e1ban allok\u00e1lt adatokhoz f\u00e9r hozz\u00e1. Ha a Polkit-hez int\u00e9zett k\u00e9r\u00e9s t\u00fal hossz\u00fa ideig tart, a gyors\u00edt\u00f3t\u00e1r elemei t\u00f6rl\u0151dnek, miel\u0151tt a DBus m\u00f3dszer kezel\u0151je m\u00e1sodszor is h\u00edv\u00e1sra ker\u00fclne. <\/p>\n

Azok k\u00f6z\u00fcl a szolg\u00e1ltat\u00e1sok k\u00f6z\u00fcl, amelyek lehet\u0151v\u00e9 teszik a sebezhet\u0151s\u00e9g kihaszn\u00e1l\u00e1s\u00e1t, a systemd-machined emelhet\u0151 ki, amely a DBus API org.freedesktop.machine1.Image.Clone-t biztos\u00edt, ami adatokat ideiglenesen gyors\u00edt\u00f3t\u00e1rba helyez, \u00e9s aszinkron h\u00edv\u00e1sokat v\u00e9gez a Polkit-n\u00e9l. Az interf\u00e9sz
\norg.freedesktop.machine1.Image.Clone minden nem privil\u00e9giz\u00e1lt rendszerhaszn\u00e1l\u00f3 sz\u00e1m\u00e1ra el\u00e9rhet\u0151, akik k\u00e9pesek crash-elni a systemd szolg\u00e1ltat\u00e1sokat, vagy potenci\u00e1lisan k\u00f3dot futtatni root jogokkal (az exploit protot\u00edpusa eddig nem ker\u00fclt bemutat\u00e1sra). A sebezhet\u0151s\u00e9g kihaszn\u00e1l\u00e1s\u00e1ra alkalmas k\u00f3d hozz\u00e1adva<\/a><\/noindex> a systemd-machined-ben m\u00e1r 2015-ben megl\u00e9v\u0151 volt a systemd 220<\/a><\/noindex> (a RHEL 7.x rendszerben a systemd 219 fut). <\/p>\n

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

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

\u0412 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u043c \u043c\u0435\u043d\u0435\u0434\u0436\u0435\u0440\u0435 systemd \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2020-1712), \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043f\u043e\u0442\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u043e \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 \u0441\u0432\u043e\u0435\u0433\u043e \u043a\u043e\u0434\u0430 \u0441 \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u043d\u044b\u043c\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u044f\u043c\u0438 \u0447\u0435\u0440\u0435\u0437 \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0443 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u043e\u0433\u043e \u0437\u0430\u043f\u0440\u043e\u0441\u0430 \u043f\u043e \u0448\u0438\u043d\u0435 DBus. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0438\u0441\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0430 \u0432 \u0442\u0435\u0441\u0442\u043e\u0432\u043e\u043c \u0432\u044b\u043f\u0443\u0441\u043a\u0435 systemd 245-rc1 (\u0440\u0435\u0448\u0430\u044e\u0449\u0438\u0435 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0443 \u043f\u0430\u0442\u0447\u0438: 1, 2, 3). \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430 \u0432 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 Ubuntu, Fedora, RHEL (\u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u0432 RHEL 8, \u043d\u043e \u043d\u0435 \u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 RHEL 7), CentOS, […]<\/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":[],"tags":[],"class_list":["post-41582","post","type-post","status-publish","format-standard","hentry"],"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 systemd-ben, amely potenci\u00e1lisan lehet\u0151v\u00e9 teszi a jogok n\u00f6vel\u00e9s\u00e9t | ProHoster","description":"A rendszerkezel\u0151ben, a systemd-ben sebezhet\u0151s\u00e9get tal\u00e1ltak 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