{"id":109263,"date":"2023-07-05T21:10:21","date_gmt":"2023-07-05T19:10:24","guid":{"rendered":"https:\/\/prohoster.info\/?p=109263"},"modified":"2023-07-06T09:41:50","modified_gmt":"2023-07-06T07:41:50","slug":"uyazvimost-konfiguraczij-nginx-s-nekorrektnymi-nastrojkami-bloka-alias","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-konfiguraczij-nginx-s-nekorrektnymi-nastrojkami-bloka-alias","title":{"rendered":"Zranitelnost konfigurac\u00ed Nginx s nespr\u00e1vn\u00fdmi nastaven\u00edmi bloku alias.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

N\u011bkter\u00e9 servery s nginx z\u016fst\u00e1vaj\u00ed zraniteln\u00e9 v\u016f\u010di technice Nginx Alias Traversal, kter\u00e1 byla p\u0159edstavena na konferenci Blackhat ji\u017e v roce 2018 a umo\u017e\u0148uje p\u0159\u00edstup k soubor\u016fm a adres\u00e1\u0159\u016fm um\u00edst\u011bn\u00fdm mimo ko\u0159enov\u00fd adres\u00e1\u0159, kter\u00fd je ur\u010den direktivou \u201ealias\u201c. Probl\u00e9m se projevuje pouze v konfigurac\u00edch s direktivou \u201ealias\u201c um\u00edst\u011bnou uvnit\u0159 bloku \u201elocation\u201c, jej\u00ed\u017e parametr nen\u00ed ukon\u010den znakem \u201e\/\u201c, zat\u00edmco \u201ealias\u201c je ukon\u010den na \u201e\/\u201c.

\"Zranitelnost<\/center> <\/p>\n

Podstata probl\u00e9mu spo\u010d\u00edv\u00e1 v tom, \u017ee soubory pro bloky s direktivou alias jsou poskytov\u00e1ny pomoc\u00ed p\u0159ipojen\u00ed po\u017eadovan\u00e9 cesty, pot\u00e9, co byla shodov\u00e1na s maskou v direktiv\u011b location a je odstran\u011bna \u010d\u00e1st cesty ur\u010den\u00e1 v t\u00e9to masce. V uveden\u00e9m p\u0159\u00edkladu zraniteln\u00e9 konfigurace m\u016f\u017ee \u00fato\u010dn\u00edk po\u017e\u00e1dat o soubor \u201e\/img..\/test.txt\u201c a tento po\u017eadavek spad\u00e1 pod uvedenou v location masku \u201e\/img\u201c, po \u010dem\u017e zb\u00fdvaj\u00edc\u00ed \u010d\u00e1st \u201e..\/test.txt\u201c bude p\u0159ipojena k cest\u011b z direktivy alias \u201e\/var\/images\/\u201c a v\u00fdsledkem bude po\u017eadavek na soubor \u201e\/var\/images\/..\/test.txt\u201c. T\u00edmto zp\u016fsobem se m\u016f\u017ee \u00fato\u010dn\u00edk dostat k jak\u00fdmkoli soubor\u016fm v adres\u00e1\u0159i \u201e\/var\u201c, a to nejen k soubor\u016fm v \u201e\/var\/images\/\u201c, nap\u0159\u00edklad pro stahov\u00e1n\u00ed logu nginx lze odeslat po\u017eadavek \u201e\/img..\/log\/nginx\/access.log\u201c. <\/p>\n

V konfigurac\u00edch, kde hodnota direktivy alias nen\u00ed zakon\u010dena znakem \u201e\/\u201c (nap\u0159\u00edklad \u201ealias \/var\/images;\u201c), \u00fato\u010dn\u00edk nem\u016f\u017ee p\u0159ej\u00edt do nad\u0159azen\u00e9ho adres\u00e1\u0159e, ale m\u00e1 mo\u017enost po\u017e\u00e1dat o jin\u00fd adres\u00e1\u0159 v \/var, jeho\u017e n\u00e1zev za\u010d\u00edn\u00e1 shodn\u011b s uveden\u00fdm v konfiguraci. Nap\u0159\u00edklad po\u017eadavkem \u201e\/img.old\/test.txt\u201c lze z\u00edskat p\u0159\u00edstup k adres\u00e1\u0159i \u201evar\/images.old\/test.txt\u201c. <\/p>\n

Anal\u00fdza repozit\u00e1\u0159\u016f na GitHubu uk\u00e1zala, \u017ee chyby v konfiguraci nginx vedouc\u00ed k probl\u00e9mu se st\u00e1le vyskytuj\u00ed v re\u00e1ln\u00fdch projektech. Nap\u0159\u00edklad existence probl\u00e9mu byla odhalena v serverov\u00e9 \u010d\u00e1sti spr\u00e1vce hesel Bitwarden a mohla b\u00fdt vyu\u017eita k p\u0159\u00edstupu k ve\u0161ker\u00fdm soubor\u016fm v adres\u00e1\u0159i \/etc\/bitwarden (po\u017eadavky na \/attachments byly poskytov\u00e1ny z \/etc\/bitwarden\/attachments\/), v\u010detn\u011b ulo\u017een\u00e9 datab\u00e1ze s hesly \u201evault.db\u201c, certifik\u00e1tu a log\u016f, k jejich\u017e z\u00edsk\u00e1n\u00ed sta\u010dilo odeslat po\u017eadavky \u201e\/attachments..\/vault.db\u201c, \u201e\/attachments..\/identity.pfx\u201c, \u201e\/attachments..\/logs\/api.log\u201c atd.

\"Zranitelnost<\/center>
\"Zranitelnost<\/center> <\/p>\n

Metoda tak\u00e9 fungovala s Google HPC Toolkit, ve kter\u00e9m byly po\u017eadavky \/static p\u0159esm\u011brov\u00e1ny do adres\u00e1\u0159e \"..\/hpc-toolkit\/community\/front-end\/website\/static\/\". Aby \u00fato\u010dn\u00edk z\u00edskal datab\u00e1zi se skryt\u00fdm kl\u00ed\u010dem a p\u0159ihla\u0161ovac\u00edmi \u00fadaji, mohl poslat po\u017eadavky \" \/static..\/.secret_key \" a \" \/static..\/db.sqlite3 \".

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

\u041d\u0435\u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0441\u0435\u0440\u0432\u0435\u0440\u044b \u0441 nginx \u043e\u0441\u0442\u0430\u044e\u0442\u0441\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u044b \u0434\u043b\u044f \u0442\u0435\u0445\u043d\u0438\u043a\u0438 Nginx Alias Traversal, \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u0431\u044b\u043b\u0430 \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0435\u043d\u0430 \u043d\u0430 \u043a\u043e\u043d\u0444\u0435\u0440\u0435\u043d\u0446\u0438\u0438 Blackhat \u0435\u0449\u0451 \u0432 2018 \u0433\u043e\u0434\u0443 \u0438 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u0434\u043e\u0441\u0442\u0443\u043f \u043a \u0444\u0430\u0439\u043b\u0430\u043c \u0438 \u043a\u0430\u0442\u0430\u043b\u043e\u0433\u0430\u043c, \u0440\u0430\u0437\u043c\u0435\u0449\u0451\u043d\u043d\u044b\u043c \u0432\u043d\u0435 \u043a\u043e\u0440\u043d\u0435\u0432\u043e\u0433\u043e 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[…]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":109264,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-109263","post","type-post","status-publish","format-standard","has-post-thumbnail","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 konfigurac\u00ed Nginx s nespr\u00e1vn\u00fdmi nastaven\u00edmi bloku alias | ProHoster","description":"N\u011bkter\u00e9 servery s nginx z\u016fst\u00e1vaj\u00ed zraniteln\u00e9 v\u016f\u010di technice Nginx Alias Traversal, kter\u00e1 byla p\u0159edstavena na konferenci Blackhat ji\u017e v roce 2018 a umo\u017e\u0148uje p\u0159\u00edstup k soubor\u016fm a adres\u00e1\u0159\u016fm um\u00edst\u011bn\u00fdm mimo.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-konfiguraczij-nginx-s-nekorrektnymi-nastrojkami-bloka-alias","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","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\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u043d\u0444\u0438\u0433\u0443\u0440\u0430\u0446\u0438\u0439 Nginx \u0441 \u043d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u044b\u043c\u0438 \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0430\u043c\u0438 \u0431\u043b\u043e\u043a\u0430 alias | 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