Der er offentliggjort oplysninger om 21 s\u00e5rbarheder i GRUB2 bootloaderen, hvoraf de fleste f\u00f8rer til bufferoverl\u00f8b og kan bruges til at omg\u00e5 UEFI Secure Boot's verificeringsmekanisme. Problemerne er indtil videre kun blevet l\u00f8st i form af en patch. Status for s\u00e5rbarhedsl\u00f8sninger i distributionerne kan vurderes p\u00e5 f\u00f8lgende sider: Debian, Ubuntu, SUSE, RHEL, Fedora. For at l\u00f8se problemerne i GRUB2 er det ikke nok blot at opdatere pakken, det er ogs\u00e5 n\u00f8dvendigt at danne nye interne digitale signaturer samt opdatere installat\u00f8rer, bootloadere, kernepakker, fwupd-firmware og shim-laget. <\/p>\n
Identificerede s\u00e5rbarheder: <\/p>\n
I de fleste Linux-distributioner bruges et lille lag shim, som er digitalt signeret af Microsoft, til verifikation af opstart i UEFI Secure Boot-tilstand. Dette lag verificerer GRUB2 med sin egen certifikat, hvilket giver distribut\u00f8rerne mulighed for ikke at skulle godkende hver opdatering af kerne og GRUB hos Microsoft. S\u00e5rbarheder i GRUB2 g\u00f8r det muligt at udf\u00f8re sin egen kode efter en vellykket verifikation af shim, men f\u00f8r operativsystemet er indl\u00e6st, ved at tr\u00e6nge ind i tillidsk\u00e6den under aktiv Secure Boot-tilstand og f\u00e5 fuld kontrol over den videre opstartsproces, for eksempel til at indl\u00e6se et andet OS, modificere komponenter i operativsystemet og omg\u00e5 Lockdown-beskyttelsen. <\/p>\n
For at blokere s\u00e5rbarheden uden at tilbagekalde den digitale signatur kan distributionerne anvende mekanismen SBAT (UEFI Secure Boot Advanced Targeting), som underst\u00f8ttes af GRUB2, shim og fwupd i de fleste popul\u00e6re Linux-distributioner. SBAT er udviklet i samarbejde med Microsoft og indeb\u00e6rer tilf\u00f8jelse af metadata til UEFI-komponenternes eksekverbare filer, som inkluderer oplysninger om producent, produkt, komponent og version. De n\u00e6vnte metadata signeres digitalt og kan separat inkluderes i lister over tilladte eller forbudte komponenter til UEFI Secure Boot. <\/p>\n
SBAT g\u00f8r det muligt at blokere brugen af den digitale signatur for specifikke versionsnumre af komponenter uden at skulle tilbagekalde n\u00f8glerne til Secure Boot. Blokering af s\u00e5rbarheder gennem SBAT kr\u00e6ver ikke brugen af en liste over tilbagekaldte UEFI-certifikater (dbx), men udf\u00f8res p\u00e5 niveauet for udskiftning af den interne n\u00f8gle til dannelse af signaturer og opdatering af GRUB2, shim og andre boot-artifakter, der leveres af distributionerne. Inden SBAT blev indf\u00f8rt, var opdatering af listen over tilbagekaldte certifikater (dbx, UEFI Revocation List) en obligatorisk betingelse for fuld blokering af s\u00e5rbarheden, da en angriber, uanset hvilken operativsystem der blev brugt, kunne bruge en bootbare enhed med en gammel, s\u00e5rbar version af GRUB2, signeret med et digitalt certifikat, til at kompromittere UEFI Secure Boot. \u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e 21 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u0431\u043e\u043b\u044c\u0448\u0438\u043d\u0441\u0442\u0432\u043e \u0438\u0437 \u043a\u043e\u0442\u043e\u0440\u044b\u0445 \u043f\u0440\u0438\u0432\u043e\u0434\u044f\u0442 \u043a \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u0431\u0443\u0444\u0435\u0440\u0430 \u0438 \u043c\u043e\u0433\u0443\u0442 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c\u0441\u044f \u0434\u043b\u044f \u043e\u0431\u0445\u043e\u0434\u0430 \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u0430 \u0432\u0435\u0440\u0438\u0444\u0438\u0446\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u0439 \u0437\u0430\u0433\u0440\u0443\u0437\u043a\u0438 UEFI Secure Boot. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u044b \u043f\u043e\u043a\u0430 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u044b \u0442\u043e\u043b\u044c\u043a\u043e \u0432 \u0432\u0438\u0434\u0435 \u043f\u0430\u0442\u0447\u0430. \u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 \u0432 \u0434\u0438\u0441\u0442\u0440\u0438\u0431\u0443\u0442\u0438\u0432\u0430\u0445 \u043c\u043e\u0436\u043d\u043e \u043e\u0446\u0435\u043d\u0438\u0442\u044c \u043d\u0430 \u0434\u0430\u043d\u043d\u044b\u0445 \u0441\u0442\u0440\u0430\u043d\u0438\u0446\u0430\u0445: Debian, Ubuntu, SUSE, RHEL, Fedora. \u0414\u043b\u044f \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f \u043f\u0440\u043e\u0431\u043b\u0435\u043c \u0432 GRUB2 \u043d\u0435\u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e \u043f\u0440\u043e\u0441\u0442\u043e […]<\/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-122049","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\udd47 21 s\u00e5rbarheder opdaget i GRUB2-bootloaderen | ProHoster","description":"Oplysninger om 21 s\u00e5rbarheder i GRUB2-bootloaderen er offentliggjort, hvoraf de fleste f\u00f8rer til buffer overflow og kan bruges til at omg\u00e5 UEFI Secure Boot verificeringsmekanismen.","canonical_url":"https:\/\/prohoster.info\/da\/blog\/news\/v-zagruzchike-grub2-vyyavlena-21-uyazvimost","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"da_DK","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\u0412 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 21 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c | ProHoster","og:description":"\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e 21 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u0431\u043e\u043b\u044c\u0448\u0438\u043d\u0441\u0442\u0432\u043e \u0438\u0437 \u043a\u043e\u0442\u043e\u0440\u044b\u0445 \u043f\u0440\u0438\u0432\u043e\u0434\u044f\u0442 \u043a \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u0431\u0443\u0444\u0435\u0440\u0430 \u0438 \u043c\u043e\u0433\u0443\u0442 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c\u0441\u044f \u0434\u043b\u044f \u043e\u0431\u0445\u043e\u0434\u0430 \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u0430 \u0432\u0435\u0440\u0438\u0444\u0438\u0446\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u043e\u0439 \u0437\u0430\u0433\u0440\u0443\u0437\u043a\u0438 UEFI Secure Boot.","og:url":"https:\/\/prohoster.info\/da\/blog\/news\/v-zagruzchike-grub2-vyyavlena-21-uyazvimost","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":"2025-02-22T00:22:05+00:00","article:modified_time":"2025-02-22T00:22:05+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"122049","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":"2026-01-23 10:50:19","breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2026-01-23 10:50:19","updated":"2026-01-23 10:50:19","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/posts\/122049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/comments?post=122049"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/posts\/122049\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/media?parent=122049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/categories?post=122049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/da\/wp-json\/wp\/v2\/tags?post=122049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
Kilde: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"