{"id":76196,"date":"2020-03-31T19:42:05","date_gmt":"2020-03-31T17:42:05","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf"},"modified":"2020-03-31T19:42:05","modified_gmt":"2020-03-31T17:42:05","slug":"uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","status":"publish","type":"post","link":"https:\/\/prohoster.info\/es\/blog\/news\/uyazvimost-v-yadre-linux-pozvolyayushhaya-povysit-svoi-privilegii-cherez-bpf","title":{"rendered":"Vulnerabilidad en el n\u00facleo de Linux que permite aumentar los privilegios a trav\u00e9s de BPF","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Publicado<\/a><\/noindex> informaci\u00f3n sobre la vulnerabilidad (CVE-2020-8835<\/a><\/noindex>) en el n\u00facleo de Linux, que fue utilizada en una competici\u00f3n Pwn2Own 2020<\/a><\/noindex> durante la demostraci\u00f3n de la explotaci\u00f3n de Ubuntu. La vulnerabilidad permiti\u00f3 a un usuario no privilegiado obtener derechos de root. Existe un exploit funcional, pero a\u00fan no ha sido publicado. La vulnerabilidad est\u00e1 presente en la subsistema eBPF, que permite ejecutar controladores para el rastreo, an\u00e1lisis del funcionamiento de los subsistemas y gesti\u00f3n del tr\u00e1fico, que se ejecutan dentro del n\u00facleo en una m\u00e1quina virtual especial con JIT.<\/p>\n

El problema es causado por un error en la funci\u00f3n __reg_bound_offset32(), utilizada para verificar las operaciones de 32 bits en el bytecode BPF. Debido a un c\u00e1lculo incorrecto de los l\u00edmites del registro, al procesar aplicaciones BPF especialmente dise\u00f1adas, surgieron condiciones para la escritura y lectura de datos fuera del buffer asignado en la memoria del n\u00facleo. El problema apareci\u00f3 en el n\u00facleo 5.5 y m\u00e1s tarde, al portar las correcciones, se traslad\u00f3 al n\u00facleo 5.4, as\u00ed como a el paquete con n\u00facleo 5.3<\/a><\/noindex>, que se ofrece en Ubuntu Linux.<\/p>\n

Para bloquear la vulnerabilidad se recomienda retroceder<\/a><\/noindex> el parche problem\u00e1tico o prohibir la ejecuci\u00f3n de aplicaciones BPF por usuarios no privilegiados estableciendo sysctl kernel.unprivileged_bpf_disabled en valor 1. Estado de la correcci\u00f3n en las distribuciones: Ubuntu<\/a><\/noindex>, Debian<\/a><\/noindex>, Arch<\/a><\/noindex>, Fedora<\/a><\/noindex> y SUSE<\/a><\/noindex> (en los n\u00facleos RHEL<\/a><\/noindex> la modificaci\u00f3n problem\u00e1tica no fue transferida).<\/p>\n

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

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

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