{"id":107877,"date":"2023-04-16T12:48:13","date_gmt":"2023-04-16T10:48:13","guid":{"rendered":"https:\/\/prohoster.info\/?p=107877"},"modified":"2023-04-17T17:50:38","modified_gmt":"2023-04-17T15:50:38","slug":"uyazvimost-v-yadre-linux-6-2-pozvolyayushhaya-obojti-zashhitu-ot-atak-spectre-v2","status":"publish","type":"post","link":"https:\/\/prohoster.info\/da\/blog\/news\/uyazvimost-v-yadre-linux-6-2-pozvolyayushhaya-obojti-zashhitu-ot-atak-spectre-v2","title":{"rendered":"S\u00e5rbarhed i Linux-kernen 6.2, der muligg\u00f8r omg\u00e5else af beskyttelse mod Spectre v2-angreb","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Der er opdaget en s\u00e5rbarhed i Linux-kernen 6.2 (CVE-2023-1998), der f\u00f8rer til deaktivering af beskyttelsen mod Spectre v2-angreb, hvilket g\u00f8r det muligt at f\u00e5 adgang til hukommelsen fra andre processer, der k\u00f8rer p\u00e5 forskellige SMT-tr\u00e5de eller Hyper-Threading, men p\u00e5 en enkelt fysisk processorkerne. S\u00e5rbarheden kan blandt andet udnyttes til at organisere datal\u00e6kager mellem virtuelle maskiner i cloud-systemer. Problemet vedr\u00f8rer udelukkende Linux-kernen 6.2 og er for\u00e5rsaget af en ukorrekt implementering af optimeringer, der skulle reducere de betydelige omkostninger ved at anvende beskyttelse mod Spectre v2. S\u00e5rbarheden er blevet rettet i den eksperimentelle version af Linux-kernen 6.3. <\/p>\n

I brugerrummet kan processer for at beskytte mod Spectre-angreb selektivt deaktivere spekulativ udf\u00f8relse af instruktioner ved hj\u00e6lp af prctl PR_SET_SPECULATION_CTRL eller anvende filtrering af systemopkald baseret p\u00e5 seccomp-mekanismen. If\u00f8lge forskere, der har identificeret problemet, har den ukorrekte optimering i kernen 6.2 efterladt systemet uden tilstr\u00e6kkelig beskyttelse. virtuelle maskiner<\/a> hos mindst \u00e9n stor cloud-udbyder, p\u00e5 trods af at mode til blokering af spectre-BTI-angreb er aktiveret via prctl. S\u00e5rbarheden ses ogs\u00e5 p\u00e5 almindelige servere<\/a> med en kerne p\u00e5 6.2, hvor indl\u00e6sningen bruger indstillingen «spectre_v2=ibrs. <\/p>\n

Essensen af s\u00e5rbarheden er den, at ved valg af beskyttelsesmetoderne IBRS eller eIBRS de indf\u00f8rte optimeringer deaktiverede brugen af STIBP (Single Thread Indirect Branch Predictors) mekanismen, som er n\u00f8dvendig for at blokere l\u00e6kager, n\u00e5r der anvendes simultan multithreading (SMT eller Hyper-Threading). Beskyttelse mod l\u00e6kager mellem tr\u00e5de leveres dog kun af eIBRS-tilstanden, ikke IBRS-tilstanden, fordi i denne tilstand nulstilles IBRS-biten, der sikrer beskyttelse mod l\u00e6kager mellem logiske kerner, af hensyn til ydeevnen, n\u00e5r kontrollen tilf\u00f8rer brugerrummet, hvilket g\u00f8r tr\u00e5dene i brugerrummet ubeskyttede mod Spectre v2-angreb.
\n
Kilde: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u044f\u0434\u0440\u0435 Linux 6.2 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-1998), \u043f\u0440\u0438\u0432\u043e\u0434\u044f\u0449\u0430\u044f \u043a \u043e\u0442\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044e \u0437\u0430\u0449\u0438\u0442\u044b \u043e\u0442 \u0430\u0442\u0430\u043a \u043a\u043b\u0430\u0441\u0441\u0430 Spectre v2, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0445 \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u0434\u043e\u0441\u0442\u0443\u043f \u043a \u043f\u0430\u043c\u044f\u0442\u0438 \u0434\u0440\u0443\u0433\u0438\u0445 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0432, \u0432\u044b\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u044b\u0445 \u0432 \u0440\u0430\u0437\u043d\u044b\u0445 \u043f\u043e\u0442\u043e\u043a\u0430\u0445 SMT \u0438\u043b\u0438 Hyper Threading, \u043d\u043e \u043d\u0430 \u043e\u0434\u043d\u043e\u043c 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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-107877","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 Linux-kernen 6.2, der muligg\u00f8r omg\u00e5else af beskyttelse mod Spectre v2-angreb | ProHoster","description":"Der er opdaget en s\u00e5rbarhed i Linux-kernen 6.2 (CVE-2023-1998), der f\u00f8rer til deaktivering af beskyttelsen mod Spectre v2-angreb, hvilket g\u00f8r det muligt at f\u00e5 adgang til hukommelsen fra andre processer, der k\u00f8rer p\u00e5 forskellige SMT-tr\u00e5de eller 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\u044f\u0434\u0440\u0435 Linux 6.2 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2023-1998), \u043f\u0440\u0438\u0432\u043e\u0434\u044f\u0449\u0430\u044f \u043a \u043e\u0442\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044e \u0437\u0430\u0449\u0438\u0442\u044b \u043e\u0442 \u0430\u0442\u0430\u043a \u043a\u043b\u0430\u0441\u0441\u0430 Spectre v2, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0445 \u043f\u043e\u043b\u0443\u0447\u0438\u0442\u044c \u0434\u043e\u0441\u0442\u0443\u043f \u043a \u043f\u0430\u043c\u044f\u0442\u0438 \u0434\u0440\u0443\u0433\u0438\u0445 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0432, \u0432\u044b\u043f\u043e\u043b\u043d\u044f\u0435\u043c\u044b\u0445 \u0432 \u0440\u0430\u0437\u043d\u044b\u0445 \u043f\u043e\u0442\u043e\u043a\u0430\u0445 SMT \u0438\u043b\u0438 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