{"id":112924,"date":"2024-01-15T17:28:03","date_gmt":"2024-01-15T15:28:03","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-patchah-red-hat-k-zagruzchiku-grub2-pozvolyayushhaya-obojti-proverku-parolya"},"modified":"2024-01-15T17:28:03","modified_gmt":"2024-01-15T15:28:03","slug":"uyazvimost-v-patchah-red-hat-k-zagruzchiku-grub2-pozvolyayushhaya-obojti-proverku-parolya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pt\/blog\/news\/uyazvimost-v-patchah-red-hat-k-zagruzchiku-grub2-pozvolyayushhaya-obojti-proverku-parolya","title":{"rendered":"Vulnerabilidade nos patches da Red Hat para o bootloader GRUB2, permitindo contornar a verifica\u00e7\u00e3o de senha","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Informa\u00e7\u00f5es sobre a vulnerabilidade (CVE-2023-4001) nos patches do carregador GRUB2, preparados pela Red Hat, foram reveladas. Essa vulnerabilidade permite que, em muitos sistemas com UEFI, se contorne a verifica\u00e7\u00e3o da senha definida no GRUB2 para restringir o acesso ao menu de inicializa\u00e7\u00e3o ou ao prompt de comando do carregador. A vulnerabilidade foi causada por uma altera\u00e7\u00e3o adicionada pela Red Hat ao pacote GRUB2 fornecido no RHEL e no Fedora Linux. O problema n\u00e3o ocorre no projeto principal do GRUB2 e afeta apenas as distribui\u00e7\u00f5es que aplicaram patches adicionais da Red Hat. <\/p>\n

O problema \u00e9 causado por um erro na l\u00f3gica de uso do UUID para a busca do carregador de dispositivo com o arquivo de configura\u00e7\u00e3o (por exemplo, \"\/boot\/efi\/EFI\/fedora\/grub.cfg\"), que cont\u00e9m o hash da senha. Para contornar a autentica\u00e7\u00e3o, um usu\u00e1rio com acesso f\u00edsico ao computador pode conectar um dispositivo externo, como um USB Flash, atribuindo a ele um UUID que repete o identificador da parti\u00e7\u00e3o de inicializa\u00e7\u00e3o \/boot do sistema atacado. <\/p>\n

Muitos sistemas UEFI processam primeiramente dispositivos externos e os colocam na lista de dispositivos detectados antes dos dispositivos fixos. Portanto, a parti\u00e7\u00e3o \/boot preparada pelo atacante ter\u00e1 prioridade no processamento, e assim o GRUB2 tentar\u00e1 carregar o arquivo de configura\u00e7\u00e3o dessa parti\u00e7\u00e3o. Durante a busca da parti\u00e7\u00e3o usando o comando \"search\" no GRUB2, \u00e9 feita a determina\u00e7\u00e3o apenas da primeira correspond\u00eancia UUID, ap\u00f3s a qual a busca \u00e9 encerrada. Se o arquivo de configura\u00e7\u00e3o principal n\u00e3o for encontrado em uma determinada parti\u00e7\u00e3o, o GRUB2 apresentar\u00e1 um prompt de comando, permitindo controle total sobre o processo de inicializa\u00e7\u00e3o subsequente. <\/p>\n

Para determinar o UUID da parti\u00e7\u00e3o, um usu\u00e1rio local n\u00e3o privilegiado pode usar a ferramenta \"lsblk\", mas um usu\u00e1rio n\u00e3o autorizado, sem acesso ao sistema, mas capaz de observar o processo de inicializa\u00e7\u00e3o, pode em algumas distribui\u00e7\u00f5es determinar o UUID a partir das mensagens de diagn\u00f3stico exibidas durante a inicializa\u00e7\u00e3o. A vulnerabilidade foi corrigida pela Red Hat atrav\u00e9s da adi\u00e7\u00e3o de um novo argumento ao comando \"search\", permitindo restringir a opera\u00e7\u00e3o de busca do UUID apenas aos dispositivos de bloco usados para iniciar o gerenciador de inicializa\u00e7\u00e3o (ou seja, a parti\u00e7\u00e3o \/boot deve estar no mesmo disco que a parti\u00e7\u00e3o do sistema EFI).
\n
Fonte: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u0430 \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 (CVE-2023-4001) \u0432 \u043f\u0430\u0442\u0447\u0430\u0445 \u043a \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0443 GRUB2, \u043f\u043e\u0434\u0433\u043e\u0442\u043e\u0432\u043b\u0435\u043d\u043d\u044b\u0445 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0435\u0439 Red Hat. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u043d\u0430 \u043c\u043d\u043e\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u0445 \u0441 UEFI \u043e\u0431\u043e\u0439\u0442\u0438 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0443 \u043f\u0430\u0440\u043e\u043b\u044f, \u0432\u044b\u0441\u0442\u0430\u0432\u043b\u0435\u043d\u043d\u043e\u0433\u043e \u0432 GRUB2 \u0434\u043b\u044f \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u0438\u044f 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[…]<\/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-112924","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 nos patches da Red Hat para o carregador GRUB2, permitindo contornar a verifica\u00e7\u00e3o de senha | ProHoster","description":"Informa\u00e7\u00e3o sobre a vulnerabilidade (CVE-2023-4001) nos patches do carregador GRUB2, preparados pela Red 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