{"id":110411,"date":"2023-10-04T08:10:45","date_gmt":"2023-10-04T06:10:45","guid":{"rendered":"https:\/\/prohoster.info\/?p=110411"},"modified":"2023-10-04T08:10:45","modified_gmt":"2023-10-04T06:10:45","slug":"uyazvimost-v-glibc-ld-so-pozvolyayushhaya-poluchit-prava-root-v-sisteme","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/news\/uyazvimost-v-glibc-ld-so-pozvolyayushhaya-poluchit-prava-root-v-sisteme","title":{"rendered":"Vulnerabilitate \u00een Glibc ld.so, care permite ob\u021binerea drepturilor root \u00een sistem","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p>Compania Qualys a identificat o vulnerabilitate periculoas\u0103 (CVE-2023-4911) \u00een linker-ul ld.so, livrat ca parte a bibliotecii standard C Glibc (GNU libc). Vulnerabilitatea permite unui utilizator local s\u0103 \u00ee\u0219i creasc\u0103 privilegiile \u00een sistem prin specificarea unor date formatate special \u00een variabila de mediu GLIBC_TUNABLES \u00eenainte de a rula un fi\u0219ier executabil cu flag-ul suid root, de exemplu, \/usr\/bin\/su.    <\/p>\n<p>Posibilitatea unei exploat\u0103ri de succes a vulnerabilit\u0103\u021bii a fost demonstrat\u0103 \u00een Fedora 37 \u0219i 38, Ubuntu 22.04 \u0219i 23.04, Debian 12 \u0219i 13. Se presupune c\u0103 vulnerabilitatea se manifest\u0103 \u0219i \u00een alte distribu\u021bii care utilizeaz\u0103 Glibc. Distribu\u021biile bazate pe biblioteca standard C Musl, precum Alpine Linux, nu sunt afectate de problem\u0103. Vulnerabilitatea a fost remediat\u0103 \u00eentr-un patch ad\u0103ugat pe 2 octombrie. Informa\u021biile despre lans\u0103rile de actualiz\u0103ri ale pachetelor \u00een distribu\u021bii pot fi urm\u0103rite pe paginile Debian, Ubuntu, RHEL, SUSE\/openSUSE, Fedora, Arch, Gentoo, ALT Linux.    <\/p>\n<p>Vulnerabilitatea este cauzat\u0103 de o modificare adus\u0103 \u00een aprilie 2021, care a fost inclus\u0103 \u00een versiunea glibc 2.34. Din cauza unei erori \u00een codul analizei \u0219irului specificat \u00een variabila de mediu GLIBC_TUNABLES, o combina\u021bie incorect\u0103 de parametrii \u00een aceast\u0103 variabil\u0103 duce la scrierea valorii analizate \u00een afara buffer-ului alocat. Problema apare atunci c\u00e2nd, \u00een loc de secven\u021bele standard \u00abname=val\u00bb, parametrii sunt defini\u021bi sub forma a dou\u0103 asign\u0103ri \u00abname=name=val\u00bb. \u00cen acest caz, atribuirea este procesat\u0103 de dou\u0103 ori, mai \u00eent\u00e2i ca \u00abname=name=val\u00bb \u0219i apoi ca \u00abname=val\u00bb. Din cauza acestei trat\u0103ri duble, rezultatul devine \u00abname=name=val:name=val\u00bb, a c\u0103rei dimensiune dep\u0103\u0219e\u0219te dimensiunea buffer-ului tunestr.      <\/p>\n<p>Cercet\u0103torii au preg\u0103tit un exploit stabil care permite ob\u021binerea drepturilor de root atunci c\u00e2nd este aplicat practic cu orice program cu flag-ul suid root. Excep\u021bie fac utilitarul sudo (care modific\u0103 valoarea ELF RUNPATH), utilitarele chage \u0219i passwd \u00een Fedora (protejate prin reguli separate SELinux) \u0219i utilitarul snap-confine \u00een Ubuntu (protejate prin reguli separate AppArmor). Metoda propus\u0103 pentru exploatare nu func\u021bioneaz\u0103 de asemenea \u00een RHEL 8 \u0219i RHEL 9, de\u0219i aceste versiuni sunt vulnerabile (pentru atac este necesar\u0103 crearea unui alt exploit). Codul exploit-ului va fi publicat ulterior, dup\u0103 eliminarea complet\u0103 a vulnerabilit\u0103\u021bii. Pentru a verifica dac\u0103 sistemul t\u0103u este vulnerabil, po\u021bi folosi comanda indicat\u0103 mai jos, care, \u00een cazul \u00een care exist\u0103 o problem\u0103, se va \u00eencheia cu o eroare: env -i \"GLIBC_TUNABLES=glibc.malloc.mxfast=glibc.malloc.mxfast=A\" \"Z=`printf '192x' 1`\" \/usr\/bin\/su --help      <\/p>\n<p>Se men\u021bioneaz\u0103, de asemenea, remedierea a \u00eenc\u0103 dou\u0103 vulnerabilit\u0103\u021bi \u00een Glibc:  <\/p>\n<ul>\n<li class=\"l\"> CVE-2023-4806 \u2014 accesarea unei zone de memorie deja eliberate (use-after-free) \u00een func\u021bia getaddrinfo(), manifest\u00e2ndu-se atunci c\u00e2nd pluginul NSS implementeaz\u0103 doar apelurile de tip call-back \u00ab_gethostbyname2_r\u00bb \u0219i \u00ab_getcanonname_r\u00bb, dar nu suport\u0103 apelul \u00ab_gethostbyname3_r\u00bb. Pentru exploatarea vulnerabilit\u0103\u021bii, serverul DNS trebuie s\u0103 returneze pentru gazda solicitat\u0103 un num\u0103r mare de adrese IPv6 \u0219i IPv4, ceea ce va duce la pr\u0103bu\u0219irea procesului care a apelat func\u021bia getaddrinfo pentru familia AF_INET6 c\u00e2nd sunt setate flag-urile AI_CANONNAME, AI_ALL \u0219i AI_V4MAPPED.\n<li class=\"l\"> CVE-2023-5156 \u2014 scurgerea con\u021binutului memoriei la apelarea func\u021biei getaddrinfo pentru familia de adrese AF_INET6 cu flag-urile AI_CANONNAME, AI_ALL \u0219i AI_V4MAPPED.        <\/ul>\n<p>Sursa: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/www.opennet.ru\/opennews\/art.shtml?num=59867\">opennet.ro<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-4911) \u0432 \u043a\u043e\u043c\u043f\u043e\u043d\u043e\u0432\u0449\u0438\u043a\u0435 ld.so, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u043c \u0432 \u0441\u043e\u0441\u0442\u0430\u0432\u0435 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u0439 \u0421\u0438-\u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 Glibc (GNU libc). \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 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u043f\u043e\u0434\u043d\u044f\u0442\u044c \u0441\u0432\u043e\u0438 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435 \u0447\u0435\u0440\u0435\u0437 \u0443\u043a\u0430\u0437\u0430\u043d\u0438\u0435 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445 \u0432 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u043e\u0439 \u043e\u043a\u0440\u0443\u0436\u0435\u043d\u0438\u044f GLIBC_TUNABLES \u043f\u0435\u0440\u0435\u0434 \u0437\u0430\u043f\u0443\u0441\u043a\u043e\u043c \u0438\u0441\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u043e\u0433\u043e \u0444\u0430\u0439\u043b\u0430 \u0441 \u0444\u043b\u0430\u0433\u043e\u043c suid root, \u043d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, \/usr\/bin\/su. \u0412\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c \u0443\u0441\u043f\u0435\u0448\u043d\u043e\u0439 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043f\u0440\u043e\u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043d\u0430 \u0432 Fedora 37 \u0438 38, [&hellip;]<\/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-110411","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.4 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-4911) \u0432 \u043a\u043e\u043c\u043f\u043e\u043d\u043e\u0432\u0449\u0438\u043a\u0435 ld.so, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u043c \u0432 \u0441\u043e\u0441\u0442\u0430\u0432\u0435 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u0439 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ob\u021binerea de drepturi root \u00een sistem | ProHoster","description":"Compania Qualys a identificat o vulnerabilitate periculoas\u0103 (CVE-2023-4911) \u00een linkerul ld.so, livrat \u00eempreun\u0103 cu biblioteca de sistem C Glibc (GNU libc).","canonical_url":"https:\/\/prohoster.info\/ro\/blog\/news\/uyazvimost-v-glibc-ld-so-pozvolyayushhaya-poluchit-prava-root-v-sisteme","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"ro_RO","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 Glibc ld.so, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u043f\u0440\u0430\u0432\u0430 root \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u0435 | ProHoster","og:description":"\u041a\u043e\u043c\u043f\u0430\u043d\u0438\u044f Qualys \u0432\u044b\u044f\u0432\u0438\u043b\u0430 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-4911) \u0432 \u043a\u043e\u043c\u043f\u043e\u043d\u043e\u0432\u0449\u0438\u043a\u0435 ld.so, \u043f\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u043c\u043e\u043c \u0432 \u0441\u043e\u0441\u0442\u0430\u0432\u0435 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u0439 \u0421\u0438-\u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0438 Glibc (GNU 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