{"id":120801,"date":"2024-12-01T03:46:13","date_gmt":"2024-12-01T01:46:16","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/vyyavlen-uefi-butkit-bootkitty-podstavlyayushhij-vredonosnyj-kod-v-zagruzhaemoe-yadro-linux"},"modified":"2024-12-01T03:46:13","modified_gmt":"2024-12-01T01:46:16","slug":"vyyavlen-uefi-butkit-bootkitty-podstavlyayushhij-vredonosnyj-kod-v-zagruzhaemoe-yadro-linux","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pt\/blog\/news\/vyyavlen-uefi-butkit-bootkitty-podstavlyayushhij-vredonosnyj-kod-v-zagruzhaemoe-yadro-linux","title":{"rendered":"Foi detectado o bootkit UEFI Bootkitty, que insere c\u00f3digo malicioso no n\u00facleo do Linux carregado","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Pesquisadores da ESET identificaram um novo bootkit chamado «Bootkitty», que \u00e9 instalado ap\u00f3s a invas\u00e3o do sistema em vez do carregador GRUB e \u00e9 utilizado para inserir componentes maliciosos no n\u00facleo do Linux, permitindo assim que o invasor controle o sistema de forma oculta e realize suas a\u00e7\u00f5es. Alega-se que este \u00e9 o primeiro bootkit UEFI direcionado a sistemas Linux. <\/p>\n

O Bootkitty \u00e9 armazenado no arquivo grubx64.efi na parti\u00e7\u00e3o do sistema EFI (EFI system partition, \/boot\/efi\/EFI\/ubuntu) em vez do carregador GRUB padr\u00e3o. Ap\u00f3s a ativa\u00e7\u00e3o pelo firmware UEFI, o bootkit carrega o verdadeiro carregador GRUB2 na mem\u00f3ria e modifica o c\u00f3digo do GRUB2 residente na mem\u00f3ria, desativando a verifica\u00e7\u00e3o de integridade dos componentes a serem carregados posteriormente, al\u00e9m de adicionar um manipulador que \u00e9 chamado ap\u00f3s a descompacta\u00e7\u00e3o da imagem do n\u00facleo Linux na mem\u00f3ria. O manipulador realiza altera\u00e7\u00f5es nas fun\u00e7\u00f5es do n\u00facleo carregadas na mem\u00f3ria (desabilitando a verifica\u00e7\u00e3o de m\u00f3dulos por assinatura digital) e tamb\u00e9m altera a linha de comando do processo de inicializa\u00e7\u00e3o de « \/init » para « LD_PRELOAD=\/opt\/injector.so \/init) ». <\/p>\n

A biblioteca injector.so intercepta algumas opera\u00e7\u00f5es do SELinux e a fun\u00e7\u00e3o init_module, que \u00e9 ent\u00e3o usada para carregar o m\u00f3dulo do n\u00facleo \/opt\/dropper.ko. O m\u00f3dulo do n\u00facleo dropper.ko cria e executa o arquivo execut\u00e1vel \/opt\/observer, depois se oculta na lista de m\u00f3dulos do n\u00facleo e instala manipuladores de chamadas de sistema, como getdents e tcp4_seq_show, para ocultar o arquivo \/opt\/observer e determinado tr\u00e1fego de rede. O arquivo execut\u00e1vel \/opt\/observer carrega o m\u00f3dulo do n\u00facleo \/opt\/rootkit_loader.ko, que \u00e9 o carregador do rootkit \/opt\/rootkit.

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

Para instalar o bootkit, \u00e9 necess\u00e1rio acesso privilegiado ao sistema, e esse tipo de malware costuma ser utilizado por invasores ap\u00f3s uma invas\u00e3o ou comprometimento bem-sucedido do sistema para fixar sua presen\u00e7a futura e ocultar atividades maliciosas. A biblioteca injector.so e os m\u00f3dulos maliciosos do n\u00facleo s\u00e3o colocados na imagem do disco RAM inicial ou no sistema de arquivos pelo invasor. O carregador grubx64.efi \u00e9 colocado na parti\u00e7\u00e3o de arquivos para UEFI. <\/p>\n

Na variante Bootkitty, que caiu nas m\u00e3os de pesquisadores, a modifica\u00e7\u00e3o das fun\u00e7\u00f5es na mem\u00f3ria do n\u00facleo foi realizada com base em deslocamentos predefinidos, sem verificar a corre\u00e7\u00e3o desses deslocamentos para a vers\u00e3o do n\u00facleo carregada. Os deslocamentos utilizados no Bootkitty eram aplic\u00e1veis apenas a vers\u00f5es do n\u00facleo e do GRUB fornecidas em certas vers\u00f5es do Ubuntu, enquanto em outros sistemas levavam a falhas na inicializa\u00e7\u00e3o. Para verificar o carregador Bootkitty (grubx64.efi), foi utilizado um certificado autoassinado, o que impedia a aplica\u00e7\u00e3o do bootkit em sistemas com o modo UEFI Secure Boot ativado, a menos que o certificado do atacante fosse adicionado \u00e0 lista de certificados confi\u00e1veis no UEFI. Essas caracter\u00edsticas levaram os pesquisadores a concluir que o Bootkitty \u00e9 apenas um prot\u00f3tipo de bootkit, ainda n\u00e3o utilizado para ataques reais. <\/p>\n

Ap\u00f3s examinar as informa\u00e7\u00f5es publicadas pela ESET, os pesquisadores da Binarly Research notaram entre os artefatos relacionados ao Bootkitty imagens BMP utilizadas para explorar a vulnerabilidade LogoFAIL, que permite a execu\u00e7\u00e3o de c\u00f3digo no n\u00edvel do firmware UEFI, contornando o mecanismo UEFI Secure Boot. No contexto do Bootkitty, a explora\u00e7\u00e3o da vulnerabilidade LogoFAIL foi empregada para adicionar o certificado autoassinado do atacante, que valida o carregador do bootkit grubx64.efi, \u00e0 lista de certificados aprovados do UEFI, permitindo que o bootkit fosse executado em sistemas com UEFI Secure Boot ativo, sem necessidade de adicionar o certificado manualmente. <\/p>\n

O ataque \u00e9 realizado atrav\u00e9s da coloca\u00e7\u00e3o de uma imagem devidamente formatada em BMP na parti\u00e7\u00e3o ESP (EFI System Partition), para ser exibida pelo firmware UEFI como o logotipo do fabricante. Devido ao uso de bibliotecas vulner\u00e1veis em firmwares UEFI para manipula\u00e7\u00e3o de imagens, o processamento da imagem especialmente formatada pode resultar em um estouro de buffer e execu\u00e7\u00e3o de c\u00f3digo com privil\u00e9gios do firmware UEFI. A vulnerabilidade LogoFAIL foi descoberta h\u00e1 um ano e afeta firmwares UEFI, entre outros, utilizados em laptops da Acer, HP, Fujitsu e Lenovo. Em novas vers\u00f5es de firmwares UEFI, a quest\u00e3o foi corrigida, mas muitos dispositivos ainda em uso operam com vers\u00f5es vulner\u00e1veis dos firmwares.

\"Foi<\/center>
\n
Fonte: opennet.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\u0438 \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 ESET \u0432\u044b\u044f\u0432\u0438\u043b\u0438 \u043d\u043e\u0432\u044b\u0439 \u0431\u0443\u0442\u043a\u0438\u0442 «Bootkitty», \u0443\u0441\u0442\u0430\u043d\u0430\u0432\u043b\u0438\u0432\u0430\u0435\u043c\u044b\u0439 \u043f\u043e\u0441\u043b\u0435 \u0432\u0437\u043b\u043e\u043c\u0430 \u0441\u0438\u0441\u0442\u0435\u043c\u044b \u0432\u043c\u0435\u0441\u0442\u043e \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0430 GRUB \u0438 \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u0435\u043c\u044b\u0439 \u0434\u043b\u044f \u043f\u043e\u0434\u0441\u0442\u0430\u043d\u043e\u0432\u043a\u0438 \u0432 \u044f\u0434\u0440\u043e Linux \u0432\u0440\u0435\u0434\u043e\u043d\u043e\u0441\u043d\u044b\u0445 \u043a\u043e\u043c\u043f\u043e\u043d\u0435\u043d\u0442\u043e\u0432, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0437\u0430\u0442\u0435\u043c \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0442 \u0430\u0442\u0430\u043a\u0443\u044e\u0449\u0435\u043c\u0443 \u0441\u043a\u0440\u044b\u0442\u043e \u043a\u043e\u043d\u0442\u0440\u043e\u043b\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0441\u0438\u0441\u0442\u0435\u043c\u0443 \u0438 \u0432\u044b\u043f\u043e\u043b\u043d\u044f\u0442\u044c \u0432 \u043d\u0435\u0439 \u0441\u0432\u043e\u0438 \u0434\u0435\u0439\u0441\u0442\u0432\u0438\u044f. \u0423\u0442\u0432\u0435\u0440\u0436\u0434\u0430\u0435\u0442\u0441\u044f, \u0447\u0442\u043e \u044d\u0442\u043e \u043f\u0435\u0440\u0432\u044b\u0439 UEFI-\u0431\u0443\u0442\u043a\u0438\u0442, \u043d\u0430\u0446\u0435\u043b\u0435\u043d\u043d\u044b\u0439 \u043d\u0430 \u043f\u043e\u0440\u0430\u0436\u0435\u043d\u0438\u0435 \u0441\u0438\u0441\u0442\u0435\u043c Linux. Bootkitty \u0440\u0430\u0437\u043c\u0435\u0449\u0430\u0435\u0442\u0441\u044f \u0432 \u0444\u0430\u0439\u043b\u0435 grubx64.efi \u0432 \u0441\u0438\u0441\u0442\u0435\u043c\u043d\u043e\u043c \u0440\u0430\u0437\u0434\u0435\u043b\u0435 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":120802,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-120801","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\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\udd47Detectado o UEFI bootkit Bootkitty, que injeta c\u00f3digo malicioso no kernel Linux durante a inicializa\u00e7\u00e3o | ProHoster","description":"Pesquisadores da ESET 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