{"id":105785,"date":"2022-12-02T15:36:49","date_gmt":"2022-12-02T13:36:49","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap"},"modified":"2022-12-02T15:36:49","modified_gmt":"2022-12-02T13:36:49","slug":"root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","title":{"rendered":"Root-zranite\u013enos\u0165 v n\u00e1stroji na spr\u00e1vu bal\u00ed\u010dkov Snap.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Spolo\u010dnos\u0165 Qualys odhalila tretiu nebezpe\u010dn\u00fa zranite\u013enos\u0165 (CVE-2022-3328) v utilite snap-confine, ktor\u00e1 je dod\u00e1van\u00e1 s flagom SUID root a je volan\u00e1 procesom snapd na vytvorenie spustite\u013en\u00e9ho prostredia pre aplik\u00e1cie distribuovan\u00e9 v samostatn\u00fdch bal\u00edkoch vo form\u00e1te snap. Zranite\u013enos\u0165 umo\u017e\u0148uje lok\u00e1lnemu neopr\u00e1vnen\u00e9mu pou\u017e\u00edvate\u013eovi z\u00edska\u0165 vykonanie k\u00f3du s opr\u00e1vneniami root v predvolenej konfigur\u00e1cii Ubuntu. Probl\u00e9m bol odstr\u00e1nen\u00fd vo verzii snapd 2.57.6. Aktualiz\u00e1cie bal\u00edkov boli vydan\u00e9 pre v\u0161etky podporovan\u00e9 vetvy Ubuntu. <\/p>\n

Zauj\u00edmav\u00e9 je, \u017ee zva\u017eovan\u00e1 zranite\u013enos\u0165 bola zaveden\u00e1 po\u010das opravy podobnej zranite\u013enosti vo febru\u00e1ri v snap-confine. V\u00fdskumn\u00edkom sa podarilo pripravi\u0165 funk\u010dn\u00fd exploit, ktor\u00fd poskytuje root pr\u00edstup v Ubuntu Server 22.04, kde sa okrem zranite\u013enosti v snap-confine podie\u013eaj\u00fa aj dve zranite\u013enosti v procese multipathd (CVE-2022-41974, CVE-2022-41973), ktor\u00e9 s\u00favisia s obch\u00e1dzan\u00edm overovania opr\u00e1vnen\u00ed pri prenose privilegovan\u00fdch pr\u00edkazov a nebezpe\u010dnou manipul\u00e1ciou so symbolick\u00fdmi odkazmi. <\/p>\n

Zranite\u013enos\u0165 v snap-confine je sp\u00f4soben\u00e1 stavom pretekania vo funkcii must_mkdir_and_open_with_perms(), ktor\u00e1 bola pridan\u00e1 na ochranu pred zamenen\u00edm adres\u00e1ra \/tmp\/snap.$SNAP_NAME za symbolick\u00fd odkaz po overen\u00ed vlastn\u00edka, ale pred volan\u00edm syst\u00e9mov\u00e9ho volania mount na bind-montovanie do neho adres\u00e1rov pre bal\u00edk vo form\u00e1te snap. Pridan\u00e1 ochrana spo\u010d\u00edvala v premenovan\u00ed adres\u00e1ra \/tmp\/snap.$SNAP_NAME na in\u00fd adres\u00e1r v \/tmp so n\u00e1hodn\u00fdm menom, ak existuje a nepatr\u00ed pou\u017e\u00edvate\u013eovi root. <\/p>\n

Pri prev\u00e1dzke oper\u00e1cie premenovania adres\u00e1ra \/tmp\/snap.$SNAP_NAME vedci vyu\u017eili to, \u017ee snap-confine tie\u017e vytv\u00e1ra adres\u00e1r \/tmp\/snap.rootfs_XXXXXX pre korene obsahu bal\u00edka snap. \u010cas\u0165 «XXXXXX» v n\u00e1zve je vybran\u00e1 n\u00e1hodne pomocou mkdtemp(), ale bal\u00edk s n\u00e1zvom «rootfs_XXXXXX» m\u00f4\u017ee prejs\u0165 kontrolou vo funkcii sc_instance_name_validate (t.j. my\u0161lienka je, \u017ee n\u00e1zov $SNAP_NAME by mal nadobudn\u00fa\u0165 hodnotu «rootfs_XXXXXX» a potom oper\u00e1cia premenovania povedie k prep\u00edsaniu adres\u00e1ra \/tmp\/snap.rootfs_XXXXXX s kore\u0148om snap). <\/p>\n

Aby sa dosiahlo s\u00fa\u010dasn\u00e9 pou\u017e\u00edvanie \/tmp\/snap.rootfs_XXXXXX a premenovanie \/tmp\/snap.$SNAP_NAME, boli spusten\u00e9 dva in\u0161tancie snap-confine. Ke\u010f prv\u00e1 in\u0161tancia vytvorila \/tmp\/snap.rootfs_XXXXXX, proces sa zablokoval a spustila sa druh\u00e1 in\u0161tancia s n\u00e1zvom bal\u00edka rootfs_XXXXXX, \u010do sp\u00f4sobilo, \u017ee do\u010dasn\u00fd adres\u00e1r \/tmp\/snap.$SNAP_NAME druhej in\u0161tancie sa stal kore\u0148ov\u00fdm adres\u00e1rom \/tmp\/snap.rootfs_XXXXXX prvej. Hne\u010f po vykonan\u00ed premenovania sa druh\u00e1 in\u0161tancia havarovala a \/tmp\/snap.rootfs_XXXXXX sa nahradilo manipul\u00e1ciou so prete\u010den\u00edm, ako pri zneu\u017eit\u00ed febru\u00e1rovej zranite\u013enosti. Po nahraden\u00ed prvej in\u0161tancie bola zru\u0161en\u00e1 blok\u00e1cia a \u00fato\u010dn\u00edci z\u00edskali pln\u00fa kontrolu nad kore\u0148ov\u00fdm adres\u00e1rom snap. <\/p>\n

Na poslednom kroku sa vytvoril symbolick\u00fd odkaz \/tmp\/snap.rootfs_XXXXXX\/tmp, ktor\u00fd bol pou\u017eit\u00fd funkciou sc_bootstrap_mount_namespace() na bind-montovanie zapisovate\u013en\u00e9ho re\u00e1lneho adres\u00e1ra \/tmp do ak\u00e9hoko\u013evek adres\u00e1ra FS, ke\u010f\u017ee volanie mount() sleduje symbolick\u00e9 odkazy pred montovan\u00edm. Tak\u00e9to montovanie je blokovan\u00e9 obmedzeniami AppArmor, ale na ob\u00eddenie tejto blok\u00e1cie boli v exploite vyu\u017eit\u00e9 dve pomocn\u00e9 zranite\u013enosti v multipathd.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u0442\u0440\u0435\u0442\u044c\u044e \u0432 \u044d\u0442\u043e\u043c\u0443 \u0433\u043e\u0434\u0443 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-3328) \u0432 \u0443\u0442\u0438\u043b\u0438\u0442\u0435 snap-confine, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u0439 \u0441 \u0444\u043b\u0430\u0433\u043e\u043c SUID root \u0438 \u0432\u044b\u0437\u044b\u0432\u0430\u0435\u043c\u043e\u0439 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u043c snapd \u0434\u043b\u044f \u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u0438\u0441\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u043e\u0433\u043e \u043e\u043a\u0440\u0443\u0436\u0435\u043d\u0438\u044f \u0434\u043b\u044f \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0439, \u0440\u0430\u0441\u043f\u0440\u043e\u0441\u0442\u0440\u0430\u043d\u044f\u0435\u043c\u044b\u0445 \u0432 \u0441\u0430\u043c\u043e\u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u044b\u0445 \u043f\u0430\u043a\u0435\u0442\u0430\u0445 \u0432 \u0444\u043e\u0440\u043c\u0430\u0442\u0435 snap. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \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 \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043a\u043e\u0434\u0430 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root \u0432 \u043a\u043e\u043d\u0444\u0438\u0433\u0443\u0440\u0430\u0446\u0438\u0438 Ubuntu \u043f\u043e \u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430 \u0432 \u0432\u044b\u043f\u0443\u0441\u043a\u0435 […]<\/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-105785","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\udd47Root-zranite\u013enos\u0165 v n\u00e1stroji na spr\u00e1vu bal\u00edkov Snap | ProHoster","description":"Spolo\u010dnos\u0165 Qualys odhalila tretiu v tomto roku nebezpe\u010dn\u00fa zranite\u013enos\u0165 (CVE-2022-3328) v n\u00e1stroji snap-confine, dod\u00e1vanom s vlajkou SUID root a volanom procesom snapd pre vytvorenie vykon\u00e1vacieho prostredia.","canonical_url":"https:\/\/prohoster.info\/sk\/blog\/news\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sk_SK","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\udd47Root-\u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 \u0438\u043d\u0441\u0442\u0440\u0443\u043c\u0435\u043d\u0442\u0430\u0440\u0438\u0438 \u0443\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u0438\u044f \u043f\u0430\u043a\u0435\u0442\u0430\u043c\u0438 Snap | ProHoster","og:description":"\u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u0442\u0440\u0435\u0442\u044c\u044e \u0432 \u044d\u0442\u043e\u043c\u0443 \u0433\u043e\u0434\u0443 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-3328) \u0432 \u0443\u0442\u0438\u043b\u0438\u0442\u0435 snap-confine, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u0439 \u0441 \u0444\u043b\u0430\u0433\u043e\u043c SUID root \u0438 \u0432\u044b\u0437\u044b\u0432\u0430\u0435\u043c\u043e\u0439 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u043c snapd \u0434\u043b\u044f \u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u0438\u0441\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u043e\u0433\u043e \u043e\u043a\u0440\u0443\u0436\u0435\u043d\u0438\u044f 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