{"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\/pl\/blog\/news\/uyazvimost-konfiguraczij-nginx-s-nekorrektnymi-nastrojkami-bloka-alias","title":{"rendered":"Luka w konfiguracji Nginx z niepoprawnymi ustawieniami bloku alias","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Niekt\u00f3re serwery z nginx s\u0105 nadal podatne na technik\u0119 Nginx Alias Traversal, kt\u00f3ra zosta\u0142a zaproponowana na konferencji Blackhat w 2018 roku i pozwala na uzyskanie dost\u0119pu do plik\u00f3w i katalog\u00f3w umieszczonych poza g\u0142\u00f3wnym katalogiem okre\u015blonym w dyrektywie «alias». Problem wyst\u0119puje tylko w konfiguracjach z dyrektyw\u0105 «alias» umieszczon\u0105 w bloku «location», kt\u00f3rej parametr nie ko\u0144czy si\u0119 na znak «\\\/», podczas gdy «alias» ko\u0144czy si\u0119 na «\\\/».

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

Istota problemu polega na tym, \u017ce pliki dla blok\u00f3w z dyrektyw\u0105 alias s\u0105 zwracane przez do\u0142\u0105czenie \u017c\u0105danego \u015bcie\u017cki po dopasowaniu jej do wzorca z dyrektywy location i wyci\u0119ciu wskazanej w tym wzorze cz\u0119\u015bci \u015bcie\u017cki. W pokazanym powy\u017cej przyk\u0142adzie podatnej konfiguracji atakuj\u0105cy mo\u017ce za\u017c\u0105da\u0107 pliku «\\\/img..\\\/test.txt» i to \u017c\u0105danie podpadnie pod wskazany w location wz\u00f3r «\\\/img», po czym pozostaj\u0105cy ogon «..\\\/test.txt» zostanie do\u0142\u0105czony do \u015bcie\u017cki z dyrektywy alias «\\\/var\\\/images\\\/» i ostatecznie zostanie za\u017c\u0105dany plik «\\\/var\\\/images\\\/..\\\/test.txt». W ten spos\u00f3b atakuj\u0105cy mo\u017ce uzyska\u0107 dost\u0119p do dowolnych plik\u00f3w w katalogu «\\\/var», a nie tylko do plik\u00f3w w «\\\/var\\\/images\\\/», na przyk\u0142ad, aby pobra\u0107 log nginx, mo\u017cna wys\u0142a\u0107 \u017c\u0105danie «\\\/img..\\\/log\\\/nginx\\\/access.log». <\/p>\n

W konfiguracjach, w kt\u00f3rych warto\u015b\u0107 dyrektywy alias nie ko\u0144czy si\u0119 znakiem «\\\/» (na przyk\u0142ad «alias \\\/var\\\/images;»), atakuj\u0105cy nie mo\u017ce przej\u015b\u0107 do katalogu nadrz\u0119dnego, ale ma mo\u017cliwo\u015b\u0107 \u017c\u0105dania innego katalogu w \\\/var, kt\u00f3rego nazwa zaczyna si\u0119 tak samo jak podana w konfiguracji. Na przyk\u0142ad, \u017c\u0105daj\u0105c «\\\/img.old\\\/test.txt» mo\u017cna uzyska\u0107 dost\u0119p do katalogu «var\\\/images.old\\\/test.txt». <\/p>\n

Analiza repozytori\u00f3w na GitHubie pokaza\u0142a, \u017ce prowadz\u0105ce do problemu b\u0142\u0119dy w konfiguracji nginx wci\u0105\u017c wyst\u0119puj\u0105 w rzeczywistych projektach. Na przyk\u0142ad, zidentyfikowano problem w cz\u0119\u015bci serwerowej mened\u017cera hase\u0142 Bitwarden, kt\u00f3ry m\u00f3g\u0142 by\u0107 wykorzystywany do uzyskania dost\u0119pu do wszystkich plik\u00f3w w katalogu \\\/etc\\\/bitwarden (\u017c\u0105dania \\\/attachments by\u0142y zwracane z \\\/etc\\\/bitwarden\\\/attachments\\\/), w tym przechowywanej tam bazy danych z has\u0142ami «vault.db», certyfikatu oraz log\u00f3w, do uzyskania kt\u00f3rych wystarczy\u0142o wys\u0142a\u0107 \u017c\u0105dania «\\\/attachments..\\\/vault.db», «\\\/attachments..\\\/identity.pfx», «\\\/attachments..\\\/logs\\\/api.log» i tym podobne.

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

Metoda ta r\u00f3wnie\u017c dzia\u0142a\u0142a z Google HPC Toolkit, w kt\u00f3rym zapytania \/static by\u0142y przekierowywane do katalogu \"..\\\/hpc-toolkit\\\/community\\\/front-end\\\/website\\\/static\\\/\". Aby uzyska\u0107 baz\u0119 danych z kluczem tajnym i danymi uwierzytelniaj\u0105cymi, atakuj\u0105cy m\u00f3g\u0142 wys\u0142a\u0107 zapytania \"\\\/static..\\\/\\.secret_key\" oraz \"\\\/static..\\\/db.sqlite3\".

\"Luka<\/center>
\n
\u0179r\u00f3d\u0142o: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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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\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\udd47Podatno\u015b\u0107 konfiguracji Nginx z nieprawid\u0142owymi ustawieniami bloku alias | ProHoster","description":"Niekt\u00f3re serwery z nginx nadal s\u0105 podatne na technik\u0119 Nginx Alias Traversal, kt\u00f3ra zosta\u0142a zaproponowana na konferencji Blackhat w 2018 roku i umo\u017cliwia dost\u0119p do plik\u00f3w i katalog\u00f3w znajduj\u0105cych si\u0119 poza nimi.","canonical_url":"https:\/\/prohoster.info\/pl\/blog\/news\/uyazvimost-konfiguraczij-nginx-s-nekorrektnymi-nastrojkami-bloka-alias","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"pl_PL","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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