{"id":103374,"date":"2022-02-18T03:37:22","date_gmt":"2022-02-18T01:37:22","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/lokalnye-root-uyazvimosti-v-instrumentarii-upravleniya-paketami-snap"},"modified":"2022-02-18T03:37:22","modified_gmt":"2022-02-18T01:37:22","slug":"lokalnye-root-uyazvimosti-v-instrumentarii-upravleniya-paketami-snap","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sl\/blog\/news\/lokalnye-root-uyazvimosti-v-instrumentarii-upravleniya-paketami-snap","title":{"rendered":"Lokalne root ranljivosti v orodjih za upravljanje paketov Snap","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Podjetje Qualys je odkrilo dve ranljivosti (CVE-2021-44731, CVE-2021-44730) v orodju snap-confine, ki se dobavlja z zastavico SUID root in ga kli\u010de proces snapd za oblikovanje izvr\u0161nega okolja za aplikacije, dobavljene v samostojnih paketih v formatu snap. Ranljivosti omogo\u010dajo lokalnemu neprivilegiranemu uporabniku, da dose\u017ee izvajanje kode s pravicami root v sistemu. Te te\u017eave so bile odpravljene v dana\u0161nji posodobitvi paketov snapd za Ubuntu 21.10, 20.04 in 18.04. <\/p>\n

Prva ranljivost (CVE-2021-44730) omogo\u010da napad preko manipulacije z trdimi povezavami, vendar zahteva, da se izklopi sistemska za\u0161\u010dita trdih povezav (nastavitev sysctl fs.protected_hardlinks na 0). Te\u017eava je povzro\u010dena z nepravilno preverjanjem lokacije izvr\u0161nih datotek pomo\u017enih programov snap-update-ns in snap-discard-ns, ki se za\u017eenejo s pravicami root. Pot do teh datotek se izra\u010duna v funkciji sc_open_snapd_tool() na podlagi lastne poti iz \/proc\/self\/exe, kar omogo\u010da ustvarjanje trde povezave do snap-confine v svojem imeniku in namestitev svojih razli\u010dic orodij snap-update-ns in snap-discard-ns v ta imenik. Po zagonu preko trde povezave snap-confine s pravicami root v trenutnem imeniku za\u017eene datoteke snap-update-ns in snap-discard-ns, ki jih je nadzoroval napadalec. <\/p>\n

\u0412\u0442\u043e\u0440\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432\u044b\u0437\u0432\u0430\u043d\u0430 \u0441\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435\u043c \u0433\u043e\u043d\u043a\u0438 \u0438 \u043c\u043e\u0436\u0435\u0442 \u0431\u044b\u0442\u044c \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0430 \u0432 \u043a\u043e\u043d\u0444\u0438\u0433\u0443\u0440\u0430\u0446\u0438\u0438 Ubuntu Desktop \u043f\u043e \u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e. \u0414\u043b\u044f \u0443\u0441\u043f\u0435\u0448\u043d\u043e\u0439 \u0440\u0430\u0431\u043e\u0442\u044b \u044d\u043a\u0441\u043f\u043b\u043e\u0438\u0442\u0430 \u0432 Ubuntu Server \u0442\u0440\u0435\u0431\u0443\u0435\u0442\u0441\u044f \u0432\u044b\u0431\u043e\u0440 \u043f\u0440\u0438 \u0443\u0441\u0442\u0430\u043d\u043e\u0432\u043a\u0435 \u043e\u0434\u043d\u043e\u0433\u043e \u0438\u0437 \u043f\u0430\u043a\u0435\u0442\u043e\u0432 \u0438\u0437 \u0441\u0435\u043a\u0446\u0438\u0438 «Featured Server Snaps». \u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0433\u043e\u043d\u043a\u0438 \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u0432 \u0444\u0443\u043d\u043a\u0446\u0438\u0438 setup_private_mount(), \u0432\u044b\u0437\u044b\u0432\u0430\u0435\u043c\u043e\u0439 \u0432\u043e \u0432\u0440\u0435\u043c\u044f \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u043a\u0438 \u043f\u0440\u043e\u0441\u0442\u0440\u0430\u043d\u0441\u0442\u0432\u0430 \u0438\u043c\u0451\u043d \u0442\u043e\u0447\u0435\u043a \u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u0434\u043b\u044f \u043f\u0430\u043a\u0435\u0442\u0430 snap. \u0414\u0430\u043d\u043d\u0430\u044f \u0444\u0443\u043d\u043a\u0446\u0438\u044f \u0441\u043e\u0437\u0434\u0430\u0451\u0442 \u0432\u0440\u0435\u043c\u0435\u043d\u043d\u044b\u0439 \u043a\u0430\u0442\u0430\u043b\u043e\u0433 «\/tmp\/snap.$SNAP_NAME\/tmp» \u0438\u043b\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u0442 \u0443\u0436\u0435 \u0441\u0443\u0449\u0435\u0441\u0442\u0432\u0443\u044e\u0449\u0438\u0439 \u0434\u043b\u044f bind-\u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u043d\u0438\u044f \u0432 \u043d\u0435\u0433\u043e \u043a\u0430\u0442\u0430\u043b\u043e\u0433\u043e\u0432 \u0434\u043b\u044f \u043f\u0430\u043a\u0435\u0442\u0430 \u0432 \u0444\u043e\u0440\u043c\u0430\u0442\u0435 snap. <\/p>\n

\u0422\u0430\u043a \u043a\u0430\u043a \u0438\u043c\u044f \u0432\u0440\u0435\u043c\u0435\u043d\u043d\u043e\u0433\u043e \u043a\u0430\u0442\u0430\u043b\u043e\u0433\u0430 \u043f\u0440\u0435\u0434\u0441\u043a\u0430\u0437\u0443\u0435\u043c\u043e, \u0430\u0442\u0430\u043a\u0443\u044e\u0449\u0438\u0439 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0434\u043c\u0435\u043d\u0438\u0442\u044c \u0435\u0433\u043e \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u043d\u0430 \u0441\u0438\u043c\u0432\u043e\u043b\u0438\u0447\u0435\u0441\u043a\u0443\u044e \u0441\u0441\u044b\u043b\u043a\u0443 \u0432 \u043c\u043e\u043c\u0435\u043d\u0442 \u043f\u043e\u0441\u043b\u0435 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0438 \u0432\u043b\u0430\u0434\u0435\u043b\u044c\u0446\u0430, \u043d\u043e \u043f\u0435\u0440\u0435\u0434 \u043e\u0431\u0440\u0430\u0449\u0435\u043d\u0438\u0435\u043c \u043a \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u043c\u0443 \u0432\u044b\u0437\u043e\u0432\u0443 mount. \u041d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, \u043c\u043e\u0436\u043d\u043e \u0441\u043e\u0437\u0434\u0430\u0442\u044c \u0432 \u043a\u0430\u0442\u0430\u043b\u043e\u0433\u0435 \/tmp\/snap.lxd \u0441\u0438\u043c\u0432\u043e\u043b\u0438\u0447\u0435\u0441\u043a\u0443\u044e \u0441\u0441\u044b\u043b\u043a\u0443 «\/tmp\/snap.lxd\/tmp», \u0443\u043a\u0430\u0437\u044b\u0432\u0430\u044e\u0449\u0443\u044e \u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u043b\u044c\u043d\u044b\u0439 \u043a\u0430\u0442\u0430\u043b\u043e\u0433, \u0438 \u0432\u044b\u0437\u043e\u0432 mount() \u043f\u043e\u0441\u043b\u0435\u0434\u0443\u0435\u0442 \u0437\u0430 \u0441\u0438\u043c\u0432\u043e\u043b\u0438\u0447\u0435\u0441\u043a\u043e\u0439 \u0441\u0441\u044b\u043b\u043a\u043e\u0439 \u0438 \u043f\u0440\u0438\u043c\u043e\u043d\u0442\u0438\u0440\u0443\u0435\u0442 \u043a\u0430\u0442\u0430\u043b\u043e\u0433 \u0432 \u043f\u0440\u043e\u0441\u0442\u0440\u0430\u043d\u0441\u0442\u0432\u0435 \u0438\u043c\u0451\u043d snap. \u041f\u043e\u0434\u043e\u0431\u043d\u044b\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c \u043c\u043e\u0436\u043d\u043e \u043f\u0440\u0438\u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0441\u0432\u043e\u0451 \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u0432 \/var\/lib \u0438 \u0447\u0435\u0440\u0435\u0437 \u0437\u0430\u043c\u0435\u043d\u0443 \/var\/lib\/snapd\/mount\/snap.snap-store.user-fstab \u043e\u0440\u0433\u0430\u043d\u0438\u0437\u043e\u0432\u0430\u0442\u044c \u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0432\u043e\u0435\u0433\u043e \u043a\u0430\u0442\u0430\u043b\u043e\u0433\u0430 \/etc \u0432 \u043f\u0440\u043e\u0441\u0442\u0440\u0430\u043d\u0441\u0442\u0432\u0435 \u0438\u043c\u0451\u043d snap-\u043f\u0430\u043a\u0435\u0442\u0430 \u0434\u043b\u044f \u043e\u0440\u0433\u0430\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0437\u0430\u0433\u0440\u0443\u0437\u043a\u0438 \u0441\u0432\u043e\u0435\u0439 \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root \u0447\u0435\u0440\u0435\u0437 \u0437\u0430\u043c\u0435\u043d\u0443 \/etc\/ld.so.preload. <\/p>\n

Ugotovljeno je, da je bilo ustvarjanje exploita zahtevna naloga, saj je orodje snap-confine napisano v jeziku Go z uporabo tehnik varnega programiranja, ima za\u0161\u010dito na podlagi profilov AppArmor, izvaja filtriranje sistemskih klicev na podlagi mehanizma seccomp in uporablja imenske prostore za izolacijo montiranja. Kljub temu so raziskovalcem uspelo pripraviti delujo\u010d exploit za pridobitev pravic root v sistemu. Koda exploita bo objavljena \u010dez nekaj tednov, potem ko uporabniki namestijo dane posodobitve.
\n
Izvor: 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 \u0434\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2021-44731, CVE-2021-44730) \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, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\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\u0438 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\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 \u0441\u0438\u0441\u0442\u0435\u043c\u0435. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u044b \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u044b \u0432 \u0441\u0435\u0433\u043e\u0434\u043d\u044f\u0448\u043d\u0435\u043c \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0438 \u043f\u0430\u043a\u0435\u0442\u043e\u0432 snapd \u0434\u043b\u044f Ubuntu 21.10, […]<\/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-103374","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\udd47Lokalne root ranljivosti v orodju za upravljanje paketov Snap | ProHoster","description":"Podjetje Qualys je odkrilo dve ranljivosti (CVE-2021-44731, CVE-2021-44730) v orodju snap-confine, ki je dostavljeno s SUID root zastavico in ga kli\u010de proces snapd za oblikovanje izvajalnega okolja za aplikacije.","canonical_url":"https:\/\/prohoster.info\/sl\/blog\/news\/lokalnye-root-uyazvimosti-v-instrumentarii-upravleniya-paketami-snap","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sl_SI","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\u041b\u043e\u043a\u0430\u043b\u044c\u043d\u044b\u0435 root-\u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \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 \u0434\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2021-44731, CVE-2021-44730) \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 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