{"id":105785,"date":"2022-12-02T15:36:49","date_gmt":"2022-12-02T13:36:49","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap"},"modified":"2022-12-02T15:36:49","modified_gmt":"2022-12-02T13:36:49","slug":"root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pt\/blog\/news\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","title":{"rendered":"Vulnerabilidade root na ferramenta de gerenciamento de pacotes Snap","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

A empresa Qualys identificou a terceira vulnerabilidade cr\u00edtica deste ano (CVE-2022-3328) na ferramenta snap-confine, que \u00e9 entregue com a flag SUID root e chamada pelo processo snapd para criar um ambiente de execu\u00e7\u00e3o para aplicativos distribu\u00eddos em pacotes independentes no formato snap. A vulnerabilidade permite que um usu\u00e1rio local n\u00e3o privilegiado execute c\u00f3digo com permiss\u00f5es de root na configura\u00e7\u00e3o padr\u00e3o do Ubuntu. O problema foi corrigido na vers\u00e3o snapd 2.57.6. Atualiza\u00e7\u00f5es de pacotes foram lan\u00e7adas para todos os branches suportados do Ubuntu. <\/p>\n

Curiosamente, a vulnerabilidade em quest\u00e3o foi introduzida durante a corre\u00e7\u00e3o de uma vulnerabilidade semelhante de fevereiro no snap-confine. Os pesquisadores conseguiram preparar um exploit funcional que fornece acesso root no Ubuntu Server 22.04, onde, al\u00e9m da vulnerabilidade no snap-confine, duas vulnerabilidades no processo multipathd (CVE-2022-41974, CVE-2022-41973) tamb\u00e9m foram exploradas, relacionadas a uma falha na verifica\u00e7\u00e3o de autoriza\u00e7\u00e3o ao transmitir comandos privilegiados e ao manuseio inseguro de links simb\u00f3licos. <\/p>\n

A vulnerabilidade no snap-confine \u00e9 causada por uma condi\u00e7\u00e3o de corrida na fun\u00e7\u00e3o must_mkdir_and_open_with_perms(), que foi adicionada para proteger contra a substitui\u00e7\u00e3o do diret\u00f3rio \/tmp\/snap.$SNAP_NAME por um link simb\u00f3lico ap\u00f3s a verifica\u00e7\u00e3o do propriet\u00e1rio, mas antes de chamar a system call mount para fazer um bind mount nos diret\u00f3rios do pacote no formato snap. A prote\u00e7\u00e3o adicionada envolvia renomear o diret\u00f3rio \/tmp\/snap.$SNAP_NAME para outro diret\u00f3rio em \/tmp com um nome aleat\u00f3rio, se existisse e n\u00e3o pertencesse ao usu\u00e1rio root. <\/p>\n

Durante a opera\u00e7\u00e3o de renomea\u00e7\u00e3o do diret\u00f3rio \/tmp\/snap.$SNAP_NAME, os pesquisadores aproveitaram o fato de que o snap-confine tamb\u00e9m cria o diret\u00f3rio \/tmp\/snap.rootfs_XXXXXX para o conte\u00fado do pacote snap. A parte «XXXXXX» do nome \u00e9 escolhida aleatoriamente usando mkdtemp(), mas um pacote com o nome «rootfs_XXXXXX» pode passar pela valida\u00e7\u00e3o na fun\u00e7\u00e3o sc_instance_name_validate (ou seja, a ideia \u00e9 que o nome $SNAP_NAME assuma o valor «rootfs_XXXXXX», e ent\u00e3o a opera\u00e7\u00e3o de renomea\u00e7\u00e3o resultar\u00e1 na sobrescri\u00e7\u00e3o do diret\u00f3rio \/tmp\/snap.rootfs_XXXXXX com a raiz do snap). <\/p>\n

Para que houvesse um uso simult\u00e2neo de \/tmp\/snap.rootfs_XXXXXX e a renomea\u00e7\u00e3o de \/tmp\/snap.$SNAP_NAME, duas inst\u00e2ncias do snap-confine foram iniciadas. Assim que a primeira inst\u00e2ncia criava \/tmp\/snap.rootfs_XXXXXX, o processo ficava bloqueado e a segunda inst\u00e2ncia com o nome do pacote rootfs_XXXXXX era iniciada, o que fazia com que o diret\u00f3rio tempor\u00e1rio \/tmp\/snap.$SNAP_NAME da segunda inst\u00e2ncia se tornasse o diret\u00f3rio raiz \/tmp\/snap.rootfs_XXXXXX da primeira. Logo ap\u00f3s a execu\u00e7\u00e3o da renomea\u00e7\u00e3o, a segunda inst\u00e2ncia falhava, e \/tmp\/snap.rootfs_XXXXXX era substitu\u00eddo com a manipula\u00e7\u00e3o de estado de corrida, como na explora\u00e7\u00e3o da vulnerabilidade de fevereiro. Ap\u00f3s a substitui\u00e7\u00e3o, o bloqueio de execu\u00e7\u00e3o da primeira inst\u00e2ncia era removido, e os atacantes obtinham controle total sobre o diret\u00f3rio raiz do snap. <\/p>\n

Na \u00faltima etapa, era criada uma liga\u00e7\u00e3o simb\u00f3lica \/tmp\/snap.rootfs_XXXXXX\/tmp, que era utilizada pela fun\u00e7\u00e3o sc_bootstrap_mount_namespace() para montar bind do diret\u00f3rio real grav\u00e1vel \/tmp em qualquer diret\u00f3rio do sistema de arquivos, j\u00e1 que a chamada mount() segue as liga\u00e7\u00f5es simb\u00f3licas antes de montar. Tal montagem \u00e9 bloqueada pelas restri\u00e7\u00f5es do AppArmor, mas para contornar esse bloqueio, o exploit utilizou duas vulnerabilidades auxiliares no multipathd.
\n
Fonte: 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 \u0442\u0440\u0435\u0442\u044c\u044e \u0432 \u044d\u0442\u043e\u043c\u0443 \u0433\u043e\u0434\u0443 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-3328) \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, 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\u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430 \u0432 \u0432\u044b\u043f\u0443\u0441\u043a\u0435 […]<\/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-105785","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\udd47Vulnerabilidade de root na ferramenta de gerenciamento de pacotes Snap | ProHoster","description":"A empresa Qualys identificou uma terceira vulnerabilidade cr\u00edtica este ano (CVE-2022-3328) na ferramenta snap-confine, fornecida com a flag SUID root e chamada pelo processo snapd para formar o ambiente execut\u00e1vel.","canonical_url":"https:\/\/prohoster.info\/pt\/blog\/news\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"pt_PT","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\udd47Root-\u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \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 \u0442\u0440\u0435\u0442\u044c\u044e \u0432 \u044d\u0442\u043e\u043c\u0443 \u0433\u043e\u0434\u0443 \u043e\u043f\u0430\u0441\u043d\u0443\u044e \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2022-3328) \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.","og:url":"https:\/\/prohoster.info\/pt\/blog\/news\/root-uyazvimost-v-instrumentarii-upravleniya-paketami-snap","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2022-12-02T13:36:49+00:00","article:modified_time":"2022-12-02T13:36:49+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":[],"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts\/105785","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/comments?post=105785"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts\/105785\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/media?parent=105785"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/categories?post=105785"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/tags?post=105785"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}