{"id":35693,"date":"2019-10-31T22:05:48","date_gmt":"2019-10-31T19:05:48","guid":{"rendered":"https:\/\/prohoster.info\/blog\/uyazvimost-v-amd-sev-pozvolyayushhaya-opredelit-klyuchi-shifrovaniya\/"},"modified":"2019-10-31T22:05:48","modified_gmt":"2019-10-31T19:05:48","slug":"uyazvimost-v-amd-sev-pozvolyayushhaya-opredelit-klyuchi-shifrovaniya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-amd-sev-pozvolyayushhaya-opredelit-klyuchi-shifrovaniya","title":{"rendered":"Zranitelnost v AMD SEV, kter\u00e1 umo\u017e\u0148uje odhalit \u0161ifrovac\u00ed kl\u00ed\u010de","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V\u00fdvoj\u00e1\u0159i z t\u00fdmu Google Cloud odhalili<\/a><\/noindex> zranitelnost (CVE-2019-9836) v implementaci technologie AMD SEV (Secure Encrypted Virtualization), kter\u00e1 umo\u017e\u0148uje kompromitaci dat chr\u00e1n\u011bn\u00fdch touto technologi\u00ed. AMD SEV na hardwarov\u00e9 \u00farovni zaji\u0161\u0165uje transparentn\u00ed \u0161ifrov\u00e1n\u00ed pam\u011bti virtu\u00e1ln\u00edch stroj\u016f, kdy p\u0159\u00edstup k de\u0161ifrovan\u00fdm dat\u016fm m\u00e1 pouze aktu\u00e1ln\u00ed hostitelsk\u00fd syst\u00e9m, zat\u00edmco ostatn\u00ed virtu\u00e1ln\u00ed stroje a hypervisor p\u0159i pokusu o p\u0159\u00edstup k t\u00e9to pam\u011bti dostanou za\u0161ifrovanou sadu dat.<\/p>\n

Identifikovan\u00fd probl\u00e9m umo\u017e\u0148uje pln\u00e9 obnoven\u00ed obsahu uzav\u0159en\u00e9ho PDH-kl\u00ed\u010de, kter\u00fd je zpracov\u00e1v\u00e1n na \u00farovni jednotliv\u00e9ho chr\u00e1n\u011bn\u00e9ho procesoru PSP (AMD Security Processor), nedostupn\u00e9ho pro hlavn\u00ed opera\u010dn\u00ed syst\u00e9m.
\nS PDH-kl\u00ed\u010dem \u00fato\u010dn\u00edk pak m\u016f\u017ee obnovit session key a tajnou sekvenci stanovenou p\u0159i vytvo\u0159en\u00ed virtu\u00e1ln\u00edho stroje a z\u00edskat p\u0159\u00edstup k za\u0161ifrovan\u00fdm dat\u016fm. <\/p>\n

Zranitelnost je zp\u016fsobena nedostatky v implementaci eliptick\u00fdch k\u0159ivek (ECC), kter\u00e9 se pou\u017e\u00edvaj\u00ed pro \u0161ifrov\u00e1n\u00ed a umo\u017e\u0148uj\u00ed prov\u00e9st \u00fatok<\/a><\/noindex> na obnovu parametr\u016f k\u0159ivky. B\u011bhem prov\u00e1d\u011bn\u00ed p\u0159\u00edkazu pro spu\u0161t\u011bn\u00ed chr\u00e1n\u011bn\u00e9ho virtu\u00e1ln\u00edho stroje m\u016f\u017ee \u00fato\u010dn\u00edk poslat parametry k\u0159ivky, kter\u00e9 neodpov\u00eddaj\u00ed parametr\u016fm doporu\u010den\u00fdm NIST, co\u017e povede k pou\u017eit\u00ed hodnot bodu mal\u00e9ho \u0159\u00e1du v operac\u00edch n\u00e1soben\u00ed s daty uzav\u0159en\u00e9ho kl\u00ed\u010de. <\/p>\n

Bezpe\u010dnost protokolu ECDH p\u0159\u00edmo z\u00e1vis\u00ed<\/a><\/noindex> od na \u0159\u00e1du<\/a><\/noindex> generovan\u00e9 v\u00fdchoz\u00edho bodu k\u0159ivky, jeho\u017e diskr\u00e9tn\u00ed logaritmus je velmi obt\u00ed\u017en\u00fd \u00fakol. V jednom z krok\u016f inicializace prost\u0159ed\u00ed AMD SEV se ve v\u00fdpo\u010dtech s uzav\u0159en\u00fdm kl\u00ed\u010dem pou\u017e\u00edvaj\u00ed parametry z\u00edskan\u00e9 od u\u017eivatele. V podstat\u011b se prov\u00e1d\u00ed operace n\u00e1soben\u00ed dvou bod\u016f, p\u0159i\u010dem\u017e jeden z nich odpov\u00edd\u00e1 uzav\u0159en\u00e9mu kl\u00ed\u010di. Pokud je druh\u00fd bod zjednodu\u0161en\u00fd s n\u00edzk\u00fdm \u0159\u00e1dem, m\u016f\u017ee \u00fato\u010dn\u00edk ur\u010dit parametry prvn\u00edho bodu (bity modulu pou\u017e\u00edvan\u00e9ho v operaci mocn\u011bn\u00ed po modulu) pomoc\u00ed proch\u00e1zen\u00ed v\u0161ech mo\u017en\u00fdch hodnot. Aby byl uzav\u0159en\u00fd kl\u00ed\u010d ur\u010den, mohou b\u00fdt vybran\u00e9 fragmenty zjednodu\u0161en\u00fdch \u010d\u00edsel pot\u00e9 spojeny pomoc\u00ed \u010c\u00ednsk\u00e9 v\u011bty o zbytc\u00edch<\/a><\/noindex>.<\/p>\n

Probl\u00e9m se t\u00fdk\u00e1 serverov\u00fdch platforem AMD EPYC, kter\u00e9 pou\u017e\u00edvaj\u00ed firmware SEV a\u017e do verze 0.17 build 11. Spole\u010dnost AMD ji\u017e publikovala<\/noindex> aktualizace firmwaru, kter\u00e1 p\u0159id\u00e1v\u00e1 blokaci pou\u017eit\u00ed bod\u016f, kter\u00e9 neodpov\u00eddaj\u00ed k\u0159ivce NIST. P\u0159itom d\u0159\u00edve generovan\u00e9 certifik\u00e1ty pro kl\u00ed\u010de PDH z\u016fst\u00e1vaj\u00ed platn\u00e9, co\u017e umo\u017e\u0148uje \u00fato\u010dn\u00edkovi prov\u00e9st \u00fatok migrace virtu\u00e1ln\u00edch stroj\u016f z prost\u0159ed\u00ed chr\u00e1n\u011bn\u00fdch proti zranitelnosti do prost\u0159ed\u00ed vystaven\u00fdch probl\u00e9mu. Tak\u00e9 se zmi\u0148uje mo\u017enost proveden\u00ed \u00fatoku prost\u0159ednictv\u00edm rollbacku firmwaru na starou zranitelnou verzi, ale tato mo\u017enost zat\u00edm nebyla potvrzena.<\/p>\n

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

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

\u0420\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a\u0438 \u0438\u0437 \u043a\u043e\u043c\u0430\u043d\u0434\u044b Google Cloud \u0432\u044b\u044f\u0432\u0438\u043b\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2019-9836) \u0432 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0438 AMD SEV (Secure Encrypted Virtualization), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0443\u044e \u0441\u043a\u043e\u043c\u043f\u0440\u043e\u043c\u0435\u0442\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0437\u0430\u0449\u0438\u0449\u0451\u043d\u043d\u044b\u0435 \u043f\u0440\u0438 \u043f\u043e\u043c\u043e\u0449\u0438 \u0434\u0430\u043d\u043d\u043e\u0439 \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0438 \u0434\u0430\u043d\u043d\u044b\u0435. 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\u0432\u0438\u0440\u0442\u0443\u0430\u043b\u044c\u043d\u044b\u0435 \u043c\u0430\u0448\u0438\u043d\u044b \u0438 \u0433\u0438\u043f\u0435\u0440\u0432\u0438\u0437\u043e\u0440 \u043f\u0440\u0438 \u043f\u043e\u043f\u044b\u0442\u043a\u0435 \u043e\u0431\u0440\u0430\u0449\u0435\u043d\u0438\u044f […]<\/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-35693","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\udd47Zranitelnost v AMD SEV, kter\u00e1 umo\u017e\u0148uje ur\u010dit kl\u00ed\u010de \u0161ifrov\u00e1n\u00ed | 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