{"id":93183,"date":"2020-09-04T07:42:02","date_gmt":"2020-09-04T05:42:02","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux"},"modified":"2020-09-04T07:42:02","modified_gmt":"2020-09-04T05:42:02","slug":"uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","status":"publish","type":"post","link":"https:\/\/prohoster.info\/da\/blog\/news\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","title":{"rendered":"S\u00e5rbarhed i implementeringen af AF_PACKET-sockets i Linux-kernen","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Tre \u00e5r efter b\u00f8lgen af s\u00e5rbarheder (1<\/a><\/noindex>, 2<\/a><\/noindex>, 3<\/a><\/noindex>, 4<\/a><\/noindex>, 5<\/a><\/noindex>) i AF_PACKET subsystemet i Linux-kernen opdaget<\/a><\/noindex> er der endnu et problem (CVE-2020-14386<\/a><\/noindex>), der giver en lokal, ikke-privilegeret bruger mulighed for at udf\u00f8re kode med root-rettigheder eller slippe ud af isolerede containere, hvis de har root-adgang.<\/p>\n

For at oprette en AF_PACKET socket og udnytte s\u00e5rbarheden kr\u00e6ves der CAP_NET_RAW bef\u00f8jelser. Denne bef\u00f8jelse kan dog f\u00e5s af ikke-privilegerede brugere i containere, der er oprettet i systemer med aktiveret bruger-namespaces. For eksempel er bruger-namespaces som standard aktiveret i Ubuntu og Fedora, men ikke i Debian og RHEL. I Android har processen mediaserver ret til at oprette AF_PACKET sockets, hvilket g\u00f8r det muligt at udnytte s\u00e5rbarheden.<\/p>\n

S\u00e5rbarheden findes i funktionen tpacket_rcv og skyldes en beregningsfejl af variablen netoff. En angreb kan skabe betingelser, hvor v\u00e6rdien i netoff bliver mindre end v\u00e6rdien i maclen, hvilket vil f\u00f8re til et overflow ved beregningen \"macoff = netoff - maclen\" og forkert efterf\u00f8lgende indstilling af en pointer til bufferen for de indkommende data. Som f\u00f8lge heraf kan en angriber initierer en skrivning fra 1 til 10 byte uden for det tildelte bufferomr\u00e5de. Det bem\u00e6rkes, at der er et exploit under udvikling, som muligg\u00f8r at opn\u00e5 root-adgang p\u00e5 systemet. <\/p>\n

Problemet har v\u00e6ret til stede i kernen siden juli 2008, dvs. det manifesterer sig i alle aktuelle kerner. En rettelse er indtil videre tilg\u00e6ngelig i form af et patch<\/a><\/noindex>. Opdateringer af pakker i distributionerne kan overv\u00e5ges p\u00e5 f\u00f8lgende sider: Ubuntu<\/a><\/noindex>, Fedora<\/a><\/noindex>, SUSE<\/a><\/noindex>, Debian<\/a><\/noindex>, RHEL<\/a><\/noindex>, Arch<\/a><\/noindex>.<\/p>\n

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

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

\u0421\u043f\u0443\u0441\u0442\u044f \u0442\u0440\u0438 \u0433\u043e\u0434\u0430 \u0441 \u043c\u043e\u043c\u0435\u043d\u0442\u0430 \u0432\u043e\u043b\u043d\u044b \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 (1, 2, 3, 4, 5) \u0432 \u043f\u043e\u0434\u0441\u0438\u0441\u0442\u0435\u043c\u0435 AF_PACKET \u044f\u0434\u0440\u0430 Linux \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0435\u0449\u0451 \u043e\u0434\u043d\u0430 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 (CVE-2020-14386), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043d\u0435\u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u043a\u043e\u0434 \u0441 \u043f\u0440\u0430\u0432\u0430\u043c\u0438 root \u0438\u043b\u0438 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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-93183","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\udd47S\u00e5rbarhed i implementeringen af AF_PACKET sockets i Linux-kernen | ProHoster","description":"Tre \u00e5r efter b\u00f8lgen af s\u00e5rbarheder (1,","canonical_url":"https:\/\/prohoster.info\/da\/blog\/news\/uyazvimost-v-realizaczii-soketov-af_packet-yadra-linux","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"da_DK","og:site_name":"ProHoster | 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