{"id":106239,"date":"2022-12-22T15:36:49","date_gmt":"2022-12-22T13:36:49","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-systemd-coredump-pozvolyayushhaya-opredelit-soderzhimoe-pamyati-suid-programm"},"modified":"2022-12-22T15:36:49","modified_gmt":"2022-12-22T13:36:49","slug":"uyazvimost-v-systemd-coredump-pozvolyayushhaya-opredelit-soderzhimoe-pamyati-suid-programm","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-systemd-coredump-pozvolyayushhaya-opredelit-soderzhimoe-pamyati-suid-programm","title":{"rendered":"Zranitelnost v systemd-coredump, kter\u00e1 umo\u017e\u0148uje ur\u010dit obsah pam\u011bti suid program\u016f","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V komponent\u011b systemd-coredump, kter\u00e1 zaji\u0161\u0165uje zpracov\u00e1n\u00ed core soubor\u016f generovan\u00fdch po hav\u00e1rii proces\u016f, byla zji\u0161t\u011bna zranitelnost (CVE-2022-4415), kter\u00e1 umo\u017e\u0148uje privilegovan\u00e9mu m\u00edstn\u00edmu u\u017eivateli zjistit obsah pam\u011bti privilegovan\u00fdch proces\u016f spu\u0161t\u011bn\u00fdch s p\u0159\u00edznakem suid root. P\u0159\u00edtomnost probl\u00e9mu v konfiguraci v\u00fdchoz\u00edm nastaven\u00ed byla potvrzena v distribuc\u00edch openSUSE, Arch, Debian, Fedora a SLES. <\/p>\n

Zranitelnost je zp\u016fsobena nedostate\u010dn\u00fdm zpracov\u00e1n\u00edm sysctl parametru fs.suid_dumpable v systemd-coredump, kter\u00fd p\u0159i v\u00fdchoz\u00edm nastaven\u00ed 2 povoluje generov\u00e1n\u00ed core dump\u016f pro procesy s p\u0159\u00edznakem suid. P\u0159edpokl\u00e1d\u00e1 se, \u017ee j\u00e1drem zapisovan\u00e9 core soubory suid proces\u016f by m\u011bly m\u00edt pr\u00e1va pro \u010dten\u00ed pouze pro u\u017eivatele root. N\u00e1stroj systemd-coredump, kter\u00fd je j\u00e1drem vol\u00e1n k ulo\u017een\u00ed core soubor\u016f, ukl\u00e1d\u00e1 core soubor pod identifik\u00e1torem root, ale d\u00e1le poskytuje p\u0159\u00edstup k core soubor\u016fm na z\u00e1klad\u011b ACL, kter\u00e1 umo\u017e\u0148uje \u010dten\u00ed na z\u00e1klad\u011b identifik\u00e1toru vlastn\u00edka, kter\u00fd proces p\u016fvodn\u011b spustil. <\/p>\n

Tato vlastnost umo\u017e\u0148uje na\u010d\u00edt\u00e1n\u00ed core soubor\u016f bez ohledu na to, \u017ee program m\u016f\u017ee zm\u011bnit identifik\u00e1tor u\u017eivatele a b\u011b\u017eet s vy\u0161\u0161\u00edmi privilegii. \u00datok spo\u010d\u00edv\u00e1 v tom, \u017ee u\u017eivatel m\u016f\u017ee spustit suid aplikaci a poslat j\u00ed sign\u00e1l SIGSEGV, po kter\u00e9m m\u016f\u017ee na\u010d\u00edst obsah core souboru, kter\u00fd zahrnuje \u00fasek pam\u011bti procesu b\u011bhem hav\u00e1rie. <\/p>\n

Nap\u0159\u00edklad u\u017eivatel m\u016f\u017ee spustit «\\\/usr\\\/bin\\\/su» a v jin\u00e9m termin\u00e1lu ukon\u010dit jeho prov\u00e1d\u011bn\u00ed p\u0159\u00edkazem «kill -s SIGSEGV `pidof su`», po \u010dem\u017e systemd-coredump ulo\u017e\u00ed core soubor do adres\u00e1\u0159e \\\/var\\\/lib\\\/systemd\\\/coredump a nastav\u00ed pro n\u011bj ACL, kter\u00e9 umo\u017e\u0148uje aktu\u00e1ln\u00edmu u\u017eivateli \u010dten\u00ed. Vzhledem k tomu, \u017ee suid n\u00e1stroj ‘su’ \u010dte z pam\u011bti obsah \\\/etc\\\/shadow, \u00fato\u010dn\u00edk m\u016f\u017ee z\u00edskat p\u0159\u00edstup k informac\u00edm o hashe hesel v\u0161ech u\u017eivatel\u016f v syst\u00e9mu. N\u00e1stroj sudo nen\u00ed \u00fatoku n\u00e1chyln\u00fd, proto\u017ee zakazuje generaci core soubor\u016f p\u0159es ulimit. <\/p>\n

Podle tvrzen\u00ed v\u00fdvoj\u00e1\u0159\u016f systemd se zranitelnost projevuje od vyd\u00e1n\u00ed systemd 247 (listopad 2020), ale podle slov v\u00fdzkumn\u00edka, kter\u00fd probl\u00e9m zjistil, je zraniteln\u00e1 i verze 246. Zranitelnost se projev\u00ed, pokud je systemd sestaven s knihovnou libacl (co\u017e je ve v\u0161ech popul\u00e1rn\u00edch distribuc\u00edch standardn\u011b). Opravy jsou zat\u00edm dostupn\u00e9 ve form\u011b z\u00e1platy. Stav oprav v distribuc\u00edch lze sledovat na n\u00e1sleduj\u00edc\u00edch str\u00e1nk\u00e1ch: Debian, Ubuntu, Gentoo, RHEL, SUSE, Fedora, Gentoo, Arch. Jako do\u010dasn\u00e9 \u0159e\u0161en\u00ed ochrany lze nastavit sysctl fs.suid_dumpable na hodnotu 0, \u010d\u00edm\u017e se zak\u00e1\u017ee p\u0159enos dump\u016f do zpracovatele systemd-coredump.
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Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u043a\u043e\u043c\u043f\u043e\u043d\u0435\u043d\u0442\u0435 systemd-coredump, \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0438\u0432\u0430\u044e\u0449\u0435\u043c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0443 core-\u0444\u0430\u0439\u043b\u043e\u0432, \u0433\u0435\u043d\u0435\u0440\u0438\u0440\u0443\u0435\u043c\u044b\u0445 \u043f\u043e\u0441\u043b\u0435 \u0430\u0432\u0430\u0440\u0438\u0439\u043d\u043e\u0433\u043e \u0437\u0430\u0432\u0435\u0440\u0448\u0435\u043d\u0438\u044f \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0432, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-4415), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c\u0443 \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0438\u0442\u044c \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u043f\u0430\u043c\u044f\u0442\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0445 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0432, \u0437\u0430\u043f\u0443\u0449\u0435\u043d\u043d\u044b\u0445 \u0441 \u0444\u043b\u0430\u0433\u043e\u043c suid root. \u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b \u0432 \u043a\u043e\u043d\u0444\u0438\u0433\u0443\u0440\u0430\u0446\u0438\u0438 \u043f\u043e \u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e \u043f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u043e \u0432 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 openSUSE, Arch, Debian, Fedora \u0438 SLES. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432\u044b\u0437\u0432\u0430\u043d\u0430 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u0435\u043c \u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u0439 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0438 sysctl-\u043f\u0430\u0440\u0430\u043c\u0435\u0442\u0440\u0430 fs.suid_dumpable \u0432 systemd-coredump, \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u043f\u0440\u0438 \u0432\u044b\u0441\u0442\u0430\u0432\u043b\u0435\u043d\u043d\u043e\u043c […]<\/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-106239","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\udd47Zranitelnost v systemd-coredump, kter\u00e1 umo\u017e\u0148uje zjistit obsah pam\u011bti suid program\u016f | ProHoster","description":"V komponent\u011b systemd-coredump, kter\u00e1 zaji\u0161\u0165uje zpracov\u00e1n\u00ed core soubor\u016f generovan\u00fdch po ne\u010dekan\u00e9m ukon\u010den\u00ed proces\u016f, byla zji\u0161t\u011bna zranitelnost (CVE-2022-4415), kter\u00e1 umo\u017e\u0148uje neopr\u00e1vn\u011bn\u00e9mu lok\u00e1ln\u00edmu u\u017eivateli.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-systemd-coredump-pozvolyayushhaya-opredelit-soderzhimoe-pamyati-suid-programm","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 \u0432 systemd-coredump, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0438\u0442\u044c \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0435 \u043f\u0430\u043c\u044f\u0442\u0438 suid-\u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c | ProHoster","og:description":"\u0412 \u043a\u043e\u043c\u043f\u043e\u043d\u0435\u043d\u0442\u0435 systemd-coredump, \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0438\u0432\u0430\u044e\u0449\u0435\u043c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0443 core-\u0444\u0430\u0439\u043b\u043e\u0432, \u0433\u0435\u043d\u0435\u0440\u0438\u0440\u0443\u0435\u043c\u044b\u0445 \u043f\u043e\u0441\u043b\u0435 \u0430\u0432\u0430\u0440\u0438\u0439\u043d\u043e\u0433\u043e \u0437\u0430\u0432\u0435\u0440\u0448\u0435\u043d\u0438\u044f \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0432, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-4415), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c\u0443 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