{"id":105601,"date":"2022-11-16T21:37:02","date_gmt":"2022-11-16T19:37:02","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot"},"modified":"2022-11-16T21:37:02","modified_gmt":"2022-11-16T19:37:02","slug":"dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sv\/blog\/news\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot","title":{"rendered":"Tv\u00e5 s\u00e5rbarheter i GRUB2 som g\u00f6r det m\u00f6jligt att kringg\u00e5 UEFI Secure Boot","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p>Information has been revealed about two vulnerabilities in the GRUB2 bootloader that could lead to code execution when using specially crafted fonts and processing certain Unicode sequences. These vulnerabilities can be exploited to bypass the UEFI Secure Boot verification mechanism.        <\/p>\n<p>Uppt\u00e4ckta s\u00e5rbarheter:  <\/p>\n<ul>\n<li class=\"l\"> CVE-2022-2601 \u2014 buffert overflow i funktionen grub_font_construct_glyph() vid bearbetning av s\u00e4rskilt formaterade typsnitt i pf2-format, som uppst\u00e5r p\u00e5 grund av felaktig ber\u00e4kning av parametern max_glyph_size och minnesallokering som medvetet \u00e4r mindre \u00e4n vad som beh\u00f6vs f\u00f6r att rymma glyphs.\n<li class=\"l\"> CVE-2022-3775 \u2014 skrivning utanf\u00f6r den allokerade minnesregionen vid rendering av vissa Unicode-sekvenser med ett s\u00e4rskilt formaterat typsnitt. Problemet finns i koden f\u00f6r typsnittshantering och orsakas av avsaknaden av tillr\u00e4ckliga kontroller f\u00f6r att f\u00f6rs\u00e4kra att glyphens bredd och h\u00f6jd matchar den tillg\u00e4ngliga bitmapens storlek. En angripare kan utforma sin inmatning p\u00e5 ett s\u00e4tt som orsakar skrivning av datakopplingen utanf\u00f6r den allokerade bufferten. Det noteras att trots sv\u00e5righeterna med att utnyttja s\u00e5rbarheten kan kodexekvering inte uteslutas.                <\/ul>\n<p> A fix has been released in the form of a patch. The status of vulnerability fixing in distributions can be assessed on the following pages: Ubuntu, SUSE, RHEL, Fedora, Debian. Simply updating the GRUB2 package is not enough to fix the issues; it is also necessary to create new internal digital signatures and update installers, bootloaders, kernel packages, fwupd firmware, and the shim layer.       <\/p>\n<p>I de flesta Linux-distributioner anv\u00e4nds ett litet shim-lager, signerat av Microsoft, f\u00f6r verifierad boot i UEFI Secure Boot-l\u00e4get. Detta lager verifierar GRUB2 med sin egen certifikat, vilket g\u00f6r att distributionsutvecklare inte beh\u00f6ver signera varje k\u00e4rn- och GRUB-uppdatering i Microsoft. S\u00e5rbarheter i GRUB2 g\u00f6r det m\u00f6jligt att k\u00f6ra egen kod efter att shim har verifierats framg\u00e5ngsrikt, men f\u00f6re operativsystemets laddning, vilket inneb\u00e4r att man kan tr\u00e4nga in i f\u00f6rtroendekedjan i aktivt l\u00e4ge Secure Boot och f\u00e5 full kontroll \u00f6ver den fortsatta bootprocessen, inklusive laddning av ett annat OS, modifiering av operativsystemets komponenter och kringg\u00e5 skyddet Lockdown.     <\/p>\n<p>F\u00f6r att blockera s\u00e5rbarheten utan att \u00e5terkalla den digitala signaturen kan distributioner anv\u00e4nda mekanismen SBAT (UEFI Secure Boot Advanced Targeting), vars st\u00f6d har implementerats f\u00f6r GRUB2, shim och fwupd i de flesta popul\u00e4ra Linux-distributioner. SBAT har utvecklats i samarbete med Microsoft och inneb\u00e4r att ytterligare metadata som inkluderar information om tillverkare, produkt, komponent och version l\u00e4ggs till i exekverbara filer f\u00f6r UEFI. Dessa metadata signeras digitalt och kan separat ing\u00e5 i listor \u00f6ver till\u00e5tna eller f\u00f6rbjudna komponenter f\u00f6r UEFI Secure Boot.      <\/p>\n<p>SBAT g\u00f6r det m\u00f6jligt att blockera anv\u00e4ndningen av digitala signaturer f\u00f6r specifika versionsnummer av komponenter utan att beh\u00f6va \u00e5terkalla nycklar f\u00f6r Secure Boot. Blockering av s\u00e5rbarheter via SBAT kr\u00e4ver inte anv\u00e4ndning av en lista \u00f6ver \u00e5terkallade UEFI-certifikat (dbx), utan sker p\u00e5 niv\u00e5 av att ers\u00e4tta den interna nyckeln f\u00f6r att skapa signaturer och uppdatera GRUB2, shim och andra bootartefakter som levereras med distributioner. Innan SBAT inf\u00f6rdes var det obligatoriskt att uppdatera listan \u00f6ver \u00e5terkallade certifikat (dbx, UEFI Revocation List) f\u00f6r att helt blockera s\u00e5rbarheten, eftersom angriparen, oavsett vilken operativsystem som anv\u00e4nds, kunde utnyttja en startbar enhet med en gammal s\u00e5rbar version av GRUB2 som var certifierad med en digital signatur.<br \/>\n<br \/>K\u00e4lla: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/www.opennet.ru\/opennews\/art.shtml?num=58130\">opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e \u0434\u0432\u0443\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044f\u0445 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0433\u0443\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u043a\u043e\u0434\u0430 \u043f\u0440\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0438 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0448\u0440\u0438\u0444\u0442\u043e\u0432 \u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0451\u043d\u043d\u044b\u0445 Unicode-\u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u0435\u0439. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\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. \u0412\u044b\u044f\u0432\u043b\u0435\u043d\u043d\u044b\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438: CVE-2022-2601 &#8212; \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435 \u0431\u0443\u0444\u0435\u0440\u0430 \u0432 \u0444\u0443\u043d\u043a\u0446\u0438\u0438 grub_font_construct_glyph() \u043f\u0440\u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0448\u0440\u0438\u0444\u0442\u043e\u0432 \u0432 \u0444\u043e\u0440\u043c\u0430\u0442\u0435 pf2, \u0432\u043e\u0437\u043d\u0438\u043a\u0430\u044e\u0449\u0435\u0435 \u0438\u0437-\u0437\u0430 \u043d\u0435\u0432\u0435\u0440\u043d\u043e\u0433\u043e \u0440\u0430\u0441\u0447\u0451\u0442\u0430 [&hellip;]<\/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-105601","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.4 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e \u0434\u0432\u0443\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044f\u0445 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0433\u0443\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u043a\u043e\u0434\u0430 \u043f\u0440\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0438 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0448\u0440\u0438\u0444\u0442\u043e\u0432 \u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0451\u043d\u043d\u044b\u0445 Unicode-\u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u0435\u0439.\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<meta name=\"author\" content=\"Yuri Gagarin\"\/>\n\t<link rel=\"canonical\" href=\"https:\/\/prohoster.info\/sv\/blog\/news\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot\" \/>\n\t\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 5.0.4\" \/>\n\t\t<meta property=\"og:locale\" content=\"sv_SE\" \/>\n\t\t<meta property=\"og:site_name\" content=\"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\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"\ud83e\udd47\u0414\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 GRUB2, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0435 \u043e\u0431\u043e\u0439\u0442\u0438 \u0437\u0430\u0449\u0438\u0442\u0443 UEFI Secure Boot | ProHoster\" \/>\n\t\t<meta property=\"og:description\" content=\"\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e \u0434\u0432\u0443\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044f\u0445 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0433\u0443\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u043a\u043e\u0434\u0430 \u043f\u0440\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0438 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0448\u0440\u0438\u0444\u0442\u043e\u0432 \u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0451\u043d\u043d\u044b\u0445 Unicode-\u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u0435\u0439.\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/prohoster.info\/sv\/blog\/news\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot\" \/>\n\t\t<meta property=\"og:image\" content=\"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg\" \/>\n\t\t<meta property=\"og:image:secure_url\" content=\"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg\" \/>\n\t\t<meta property=\"og:image:width\" content=\"350\" \/>\n\t\t<meta property=\"og:image:height\" content=\"350\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2022-11-16T19:37:02+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2022-11-16T19:37:02+00:00\" \/>\n\t\t<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/prohoster\" \/>\n\t\t<meta property=\"article:author\" content=\"https:\/\/www.facebook.com\/prohoster\" \/>\n\t\t<!-- All in One SEO -->\n\n","aioseo_head_json":{"title":"\ud83e\udd47Two vulnerabilities in GRUB2 allowing bypass of UEFI Secure Boot protection | ProHoster","description":"Information has been revealed about two vulnerabilities in the GRUB2 bootloader that could lead to code execution when using specially crafted fonts and processing certain Unicode sequences.","canonical_url":"https:\/\/prohoster.info\/sv\/blog\/news\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sv_SE","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\u0414\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u0432 GRUB2, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0435 \u043e\u0431\u043e\u0439\u0442\u0438 \u0437\u0430\u0449\u0438\u0442\u0443 UEFI Secure Boot | ProHoster","og:description":"\u0420\u0430\u0441\u043a\u0440\u044b\u0442\u044b \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u043e \u0434\u0432\u0443\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044f\u0445 \u0432 \u0437\u0430\u0433\u0440\u0443\u0437\u0447\u0438\u043a\u0435 GRUB2, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u043c\u043e\u0433\u0443\u0442 \u043f\u0440\u0438\u0432\u0435\u0441\u0442\u0438 \u043a \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u043a\u043e\u0434\u0430 \u043f\u0440\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0438 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0448\u0440\u0438\u0444\u0442\u043e\u0432 \u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u043e\u043f\u0440\u0435\u0434\u0435\u043b\u0451\u043d\u043d\u044b\u0445 Unicode-\u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u0435\u0439.","og:url":"https:\/\/prohoster.info\/sv\/blog\/news\/dve-uyazvimosti-v-grub2-pozvolyayushhie-obojti-zashhitu-uefi-secure-boot","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":"2022-11-16T19:37:02+00:00","article:modified_time":"2022-11-16T19:37:02+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":[],"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts\/105601","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/comments?post=105601"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/posts\/105601\/revisions"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/media?parent=105601"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/categories?post=105601"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/sv\/wp-json\/wp\/v2\/tags?post=105601"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}