{"id":181809,"date":"2026-05-30T14:48:10","date_gmt":"2026-05-30T12:48:10","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/obnarodovana-lpe-uyazvimost-cifswitch-v-linux-cifs-cifs-utils"},"modified":"2026-05-30T14:48:10","modified_gmt":"2026-05-30T12:48:10","slug":"obnarodovana-lpe-uyazvimost-cifswitch-v-linux-cifs-cifs-utils","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pt\/blog\/news\/obnarodovana-lpe-uyazvimost-cifswitch-v-linux-cifs-cifs-utils","title":{"rendered":"Foi revelada uma vulnerabilidade LPE do CIFSwitch no Linux CIFS\/cifs-utils","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Investigador de Seguran\u00e7a Asim Manizada<\/strong> revelou uma vulnerabilidade CIFSwitch<\/strong> \u2014 eleva\u00e7\u00e3o local de privil\u00e9gios na intera\u00e7\u00e3o entre o n\u00facleo do Linux e o pacote de usu\u00e1rio cifs-utils<\/strong>. O problema afeta o caminho de processamento CIFS\/SMB Kerberos\/SPNEGO upcall<\/strong>, ou seja, o mecanismo atrav\u00e9s do qual o cliente CIFS do n\u00facleo solicita ao helper de usu\u00e1rio dados para autentica\u00e7\u00e3o Kerberos ao montar recursos SMB. A descri\u00e7\u00e3o foi publicada ap\u00f3s o t\u00e9rmino do embargo linux-distros; o identificador CVE ainda n\u00e3o havia sido atribu\u00eddo no momento da publica\u00e7\u00e3o.<\/p>\n

<\/p>\n

A ess\u00eancia da vulnerabilidade \u00e9 que<\/a>, o que permitiu que um usu\u00e1rio n\u00e3o privilegiado chamasse request_key("cifs.spnego", …) e enviasse uma descri\u00e7\u00e3o de tecla falsificada. Em um cen\u00e1rio normal, essa string deveria ser formada pelo pr\u00f3prio cliente CIFS do n\u00facleo: ela cont\u00e9m informa\u00e7\u00f5es sobre o servidor, UID, UID de credencial, PID, objetivo do upcall e outros par\u00e2metros. No entanto, o n\u00facleo n\u00e3o verificou se a descri\u00e7\u00e3o realmente veio da subsistema CIFS, enquanto cifs.upcall, executado pelo root atrav\u00e9s da regra padr\u00e3o request-key, confiava nesses campos como dados criados pelo n\u00facleo.<\/p>\n

<\/noindex><\/noindex><\/p>\n

<\/p>\n

A vulnerabilidade n\u00e3o \u00e9 uma<\/a> \u00abfalha em qualquer Linux padr\u00e3o\u00bb. Para explora\u00e7\u00e3o, v\u00e1rias condi\u00e7\u00f5es devem ser atendidas: ter um n\u00facleo vulner\u00e1vel, cifs-utils instalado com a regra cifs.spnego, a capacidade de usu\u00e1rios n\u00e3o privilegiados criarem namespaces de usu\u00e1rio\/montagem, assim como a aus\u00eancia de bloqueios por parte do SELinux, AppArmor ou outra pol\u00edtica LSM. A mensagem no oss-security destaca que em sistemas vulner\u00e1veis isso proporciona um caminho de um usu\u00e1rio local n\u00e3o privilegiado para a execu\u00e7\u00e3o de c\u00f3digo como root.<\/p>\n

<\/noindex>
\n<\/p>\n

Tecnicamente a cadeia se constr\u00f3i em torno do fato<\/a>, que cifs.upcall pode mudar para os namespaces especificados na descri\u00e7\u00e3o falsa e executar uma solicita\u00e7\u00e3o de NSS at\u00e9 o final da libera\u00e7\u00e3o de privil\u00e9gios. Como resultado, um ambiente controlado pelo atacante pode influenciar o carregamento do m\u00f3dulo NSS pelo processo root. As descri\u00e7\u00f5es p\u00fablicas enfatizam que isso \u00e9 uma falha l\u00f3gica na fronteira entre o n\u00facleo e o espa\u00e7o do usu\u00e1rio, e n\u00e3o uma vulnerabilidade cl\u00e1ssica de corrup\u00e7\u00e3o de mem\u00f3ria.<\/p>\n

<\/noindex><\/p>\n

A corre\u00e7\u00e3o no n\u00facleo revelou-se pequena: para o tipo de chaves cifs.spnego, foi adicionada uma verifica\u00e7\u00e3o que rejeita descri\u00e7\u00f5es criadas n\u00e3o pelo pr\u00f3prio cliente CIFS com suas credenciais spnego_cred privadas. Essa abordagem fecha a classe de ataques sem altera\u00e7\u00f5es sincr\u00f4nicas obrigat\u00f3rias no cifs-utils, embora o autor ressalte que um refor\u00e7o adicional no espa\u00e7o do usu\u00e1rio ainda seja desej\u00e1vel.<\/p>\n

<\/p>\n

A AlmaLinux informou<\/a>, a l\u00f3gica b\u00e1sica est\u00e1 presente em todas as vers\u00f5es suportadas do AlmaLinux, sendo que AlmaLinux 8, 9, 10 e Kitten 10 s\u00e3o considerados afetados quando o cifs-utils estiver instalado. Os kernels corrigidos foram preparados nos reposit\u00f3rios de testing: para AlmaLinux 9 o pacote \u00e9 kernel-5.14.0-687.5.4.el9_8 ou mais recente, e para AlmaLinux 10 \u2014 kernel-6.12.0-211.7.4.el10_2 ou mais recente.<\/p>\n

<\/noindex><\/p>\n

Como medidas tempor\u00e1rias antes da instala\u00e7\u00e3o do kernel corrigido, recomenda-se remover o cifs-utils, caso o cliente SMB\/CIFS n\u00e3o esteja em uso no sistema, proibir o carregamento do m\u00f3dulo cifs, redefinir a regra cifs.spnego na chave de requisi\u00e7\u00e3o ou desativar os namespaces de usu\u00e1rio n\u00e3o privilegiados. Essas medidas alternativas podem quebrar a autentica\u00e7\u00e3o Kerberos para montagens CIFS, portanto, em servidores onde as compartilhamentos SMB autenticadas por Kerberos s\u00e3o realmente utilizados, devem ser aplicadas com cautela.<\/p>\n

O CIFSwitch \u00e9 interessante tamb\u00e9m pelo contexto de detec\u00e7\u00e3o: o autor o descreve como resultado da busca por cadeias de m\u00faltiplas etapas utilizando LLM e a representa\u00e7\u00e3o gr\u00e1fica das rela\u00e7\u00f5es entre objetos de seguran\u00e7a. Mas a conclus\u00e3o pr\u00e1tica para os administradores \u00e9 bastante direta: verificar a presen\u00e7a do cifs-utils, o estado dos namespaces de usu\u00e1rio e as atualiza\u00e7\u00f5es do kernel, especialmente em sistemas onde h\u00e1 usu\u00e1rios locais ou scripts de cont\u00eainer com recursos de namespace expandidos.<\/p>\n

Fonte: linux.org.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 Asim Manizada \u0440\u0430\u0441\u043a\u0440\u044b\u043b \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c CIFSwitch \u2014 \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u0435 \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u0438\u0435 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0439 \u0432 \u0441\u0432\u044f\u0437\u043a\u0435 \u044f\u0434\u0440\u0430 Linux \u0438 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u0441\u043a\u043e\u0433\u043e \u043f\u0430\u043a\u0435\u0442\u0430 cifs-utils. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 \u043f\u0443\u0442\u044c \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0438 CIFS\/SMB Kerberos\/SPNEGO upcall, \u0442\u043e \u0435\u0441\u0442\u044c \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c, \u0447\u0435\u0440\u0435\u0437 \u043a\u043e\u0442\u043e\u0440\u044b\u0439 CIFS-\u043a\u043b\u0438\u0435\u043d\u0442 \u044f\u0434\u0440\u0430 \u0437\u0430\u043f\u0440\u0430\u0448\u0438\u0432\u0430\u0435\u0442 \u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u0441\u043a\u043e\u0433\u043e helper\u2019\u0430 \u0434\u0430\u043d\u043d\u044b\u0435 \u0434\u043b\u044f Kerberos-\u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u0438 \u043f\u0440\u0438 \u043c\u043e\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0438 SMB-\u0440\u0435\u0441\u0443\u0440\u0441\u043e\u0432. \u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u043e \u043f\u043e\u0441\u043b\u0435 \u0438\u0441\u0442\u0435\u0447\u0435\u043d\u0438\u044f \u044d\u043c\u0431\u0430\u0440\u0433\u043e linux-distros; \u0438\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440 CVE \u043d\u0430 \u043c\u043e\u043c\u0435\u043d\u0442 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438 \u0435\u0449\u0451 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-181809","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 LPE do CIFSwitch no Linux CIFS\/cifs-utils divulgada | ProHoster","description":"O pesquisador de seguran\u00e7a Asim Manizada revelou uma vulnerabilidade do CIFSwitch \u2014 eleva\u00e7\u00e3o local de privil\u00e9gios na combina\u00e7\u00e3o do kernel Linux e do pacote de usu\u00e1rio cifs-utils.","canonical_url":"https:\/\/prohoster.info\/pt\/blog\/news\/obnarodovana-lpe-uyazvimost-cifswitch-v-linux-cifs-cifs-utils","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\udd47\u041e\u0431\u043d\u0430\u0440\u043e\u0434\u043e\u0432\u0430\u043d\u0430 LPE-\u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c CIFSwitch \u0432 Linux CIFS\/cifs-utils | ProHoster","og:description":"\u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 Asim Manizada \u0440\u0430\u0441\u043a\u0440\u044b\u043b \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c CIFSwitch \u2014 \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u0435 \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u0438\u0435 \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0439 \u0432 \u0441\u0432\u044f\u0437\u043a\u0435 \u044f\u0434\u0440\u0430 Linux \u0438 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u0441\u043a\u043e\u0433\u043e \u043f\u0430\u043a\u0435\u0442\u0430 cifs-utils.","og:url":"https:\/\/prohoster.info\/pt\/blog\/news\/obnarodovana-lpe-uyazvimost-cifswitch-v-linux-cifs-cifs-utils","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":"2026-05-30T12:48:10+00:00","article:modified_time":"2026-05-30T12:48:10+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\/181809","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\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/comments?post=181809"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/posts\/181809\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/media?parent=181809"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/categories?post=181809"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/pt\/wp-json\/wp\/v2\/tags?post=181809"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}