{"id":114581,"date":"2024-03-26T12:25:42","date_gmt":"2024-03-26T10:25:43","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/zenhammer-metod-ataki-dlya-iskazheniya-soderzhimogo-pamyati-na-platformah-amd-zen"},"modified":"2024-03-26T12:25:42","modified_gmt":"2024-03-26T10:25:43","slug":"zenhammer-metod-ataki-dlya-iskazheniya-soderzhimogo-pamyati-na-platformah-amd-zen","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/zenhammer-metod-ataki-dlya-iskazheniya-soderzhimogo-pamyati-na-platformah-amd-zen","title":{"rendered":"ZenHammer \u2014 metoda \u00fatoku pro po\u0161kozen\u00ed obsahu pam\u011bti na platform\u00e1ch AMD Zen","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V\u00fdzkumn\u00edci z Cury\u0161sk\u00e9 technick\u00e9 vysok\u00e9 \u0161koly vyvinuli metodu \u00fatoku ZenHammer, co\u017e je varianta \u00fatok\u016f t\u0159\u00eddy RowHammer, zam\u011b\u0159en\u00e1 na zm\u011bnu obsahu jednotliv\u00fdch bit\u016f dynamick\u00e9 opera\u010dn\u00ed pam\u011bti (DRAM), p\u0159izp\u016fsoben\u00e1 pro pou\u017eit\u00ed na platform\u00e1ch s procesory AMD. P\u0159edchoz\u00ed metody \u00fatok\u016f t\u0159\u00eddy RowHammer byly omezeny na syst\u00e9my zalo\u017een\u00e9 na procesorech Intel, ale uskute\u010dn\u011bn\u00fd v\u00fdzkum uk\u00e1zal, \u017ee i deformace pam\u011b\u0165ov\u00fdch bun\u011bk lze dos\u00e1hnout na platform\u00e1ch s pam\u011b\u0165ov\u00fdmi \u0159adi\u010di od spole\u010dnosti AMD. <\/p>\n

Funk\u010dnost metody byla demonstrov\u00e1na na syst\u00e9mech AMD Zen 2 a Zen 3 s pam\u011bt\u00ed DDR4 od t\u0159\u00ed p\u0159edn\u00edch v\u00fdrobc\u016f (Samsung, Micron a SK Hynix). \u00datok \u00fasp\u011b\u0161n\u011b obch\u00e1z\u00ed mechanismus TRR (Target Row Refresh) implementovan\u00fd v pam\u011b\u0165ov\u00fdch \u010dipech, kter\u00fd je zam\u011b\u0159en na ochranu p\u0159ed deformac\u00ed pam\u011b\u0165ov\u00fdch bun\u011bk v sousedn\u00edch \u0159ad\u00e1ch. Podle hodnocen\u00ed v\u00fdzkumn\u00edk\u016f jsou syst\u00e9my zalo\u017een\u00e9 na procesorech AMD Zen 3 v\u00edce zraniteln\u00e9 ne\u017e syst\u00e9my s procesory Intel Coffee Lake, tak\u017ee je snaz\u0161\u00ed a efektivn\u011bji je napadnout. Na syst\u00e9mech AMD Zen 2 byla deformace bun\u011bk dosa\u017eena u 7 z 10 testovan\u00fdch \u010dip\u016f DDR4, zat\u00edmco na syst\u00e9mech Zen 3 u 6 z 10. V\u00fdzkumn\u00edci tak\u00e9 analyzovali mo\u017enost \u00fatoku na syst\u00e9my AMD Zen 4 s pam\u011bt\u00ed DDR5, ale metodu \u00fatoku vyvinutou pro DDR4 se poda\u0159ilo \u00fasp\u011b\u0161n\u011b reprodukovat pouze u 1 z 10 testovan\u00fdch pam\u011b\u0165ov\u00fdch \u010dip\u016f DDR5, p\u0159i\u010dem\u017e mo\u017enost \u00fatoku nen\u00ed vylou\u010dena, ale vy\u017eaduje v\u00fdvoj efektivn\u011bj\u0161\u00edch vzor\u016f \u010dten\u00ed vhodn\u00fdch pro za\u0159\u00edzen\u00ed DDR5. <\/p>\n

Pro pr\u00e1ci s \u010dipy AMD se poda\u0159ilo p\u0159izp\u016fsobit d\u0159\u00edve vyvinut\u00e9 exploits, kter\u00e9 m\u011bn\u00ed obsah z\u00e1znam\u016f v tabulk\u00e1ch str\u00e1nek pam\u011bti (PTE, page table entry), aby z\u00edskaly privilegium j\u00e1dra, obch\u00e1zej\u00edc\u00ed ov\u011b\u0159ov\u00e1n\u00ed hesla\/povolen\u00ed prost\u0159ednictv\u00edm modifikace pam\u011bti procesu sudo a po\u0161kozuj\u00edc\u00ed ulo\u017een\u00fd v pam\u011bti ve\u0159ejn\u00fd kl\u00ed\u010d RSA-2048 v OpenSSH k reprodukci soukrom\u00e9ho kl\u00ed\u010de. \u00datok na str\u00e1nky pam\u011bti se poda\u0159ilo reprodukovat na 7 z 10 testovan\u00fdch \u010dip\u016f DDR4, \u00fatok na kl\u00ed\u010d RSA \u2014 na 6 \u010dipech, a \u00fatok na sudo \u2014 na 4 \u010dipech, p\u0159i\u010dem\u017e doba \u00fatoku \u010dinila 164, 267 a 209 sekund, v tomto po\u0159ad\u00ed.

\"ZenHammer<\/center> <\/p>\n

Metoda m\u016f\u017ee b\u00fdt tak\u00e9 aplikov\u00e1na pro \u00fatok na syst\u00e9m prost\u0159ednictv\u00edm prohl\u00ed\u017ee\u010d\u016f, aby do\u0161lo k prov\u00e1d\u011bn\u00ed zm\u011bn z virtu\u00e1ln\u00edch stroj\u016f<\/a> nebo pro organizaci \u00fatoku p\u0159es s\u00ed\u0165. Na GitHubu je pod licenc\u00ed MIT zve\u0159ejn\u011bn zdrojov\u00fd k\u00f3d n\u00e1stroje DARE pro reverzn\u00ed in\u017een\u00fdrstv\u00ed rozlo\u017een\u00ed adres v pam\u011bti DRAM, a tak\u00e9 dv\u011b sady utilit pro fuzzing-testov\u00e1n\u00ed zkreslen\u00ed bit\u016f v pam\u011bti \u2014 ddr4_zen2_zen3_pub pro \u010dipy DDR4 (Zen 2 a Zen 3) a ddr5_zen4_pub pro \u010dipy DDR5 (Zen 4), kter\u00e9 lze pou\u017e\u00edt k testov\u00e1n\u00ed sv\u00fdch syst\u00e9m\u016f na zranitelnost v\u016f\u010di \u00fatoku.

\"ZenHammer<\/center> <\/p>\n

Pro zkreslen\u00ed bit\u016f se pou\u017e\u00edv\u00e1 metoda RowHammer, kter\u00e1 se zakl\u00e1d\u00e1 na tom, \u017ee v pam\u011bti DRAM, kter\u00e1 p\u0159edstavuje dvourozm\u011brnou matici bun\u011bk slo\u017een\u00fdch z kondenz\u00e1toru a tranzistoru, kontinu\u00e1ln\u00ed \u010dten\u00ed stejn\u00e9 oblasti pam\u011bti vede k v\u00fdkyv\u016fm nap\u011bt\u00ed a anom\u00e1li\u00edm zp\u016fsobuj\u00edc\u00edm mal\u00e9 ztr\u00e1ty n\u00e1boje sousedn\u00edch bun\u011bk. Pokud je intenzita \u010dten\u00ed vysok\u00e1, sousedn\u00ed bu\u0148ka m\u016f\u017ee ztratit dostate\u010dn\u011b velk\u00e9 mno\u017estv\u00ed n\u00e1boje a dal\u0161\u00ed regenera\u010dn\u00ed cyklus nemus\u00ed stihnout obnovit jej\u00ed p\u016fvodn\u00ed stav, co\u017e povede ke zm\u011bn\u011b hodnoty ulo\u017een\u00fdch dat v bu\u0148ce. V r\u00e1mci v\u00fdzkumu byly identifikov\u00e1ny rysy mechanism\u016f mapov\u00e1n\u00ed fyzick\u00e9 pam\u011bti a synchronizace s aktualizac\u00ed pam\u011bti v procesorech AMD, kter\u00e9 umo\u017enily rekonstrukci n\u00edzko\u00farov\u0148ov\u00e9 adresace DRAM, ur\u010den\u00ed adres sousedn\u00edch bun\u011bk, v\u00fdvoj metod obch\u00e1zen\u00ed cachov\u00e1n\u00ed, v\u00fdpo\u010det vzorc\u016f a frekvence operac\u00ed vedouc\u00edch ke ztr\u00e1t\u011b n\u00e1boje. <\/p>\n

Pro ochranu proti RowHammer v\u00fdrobci \u010dip\u016f pou\u017e\u00edvaj\u00ed mechanismus TRR (Target Row Refresh), kter\u00fd blokuje zkreslen\u00ed bun\u011bk v ur\u010dit\u00fdch p\u0159\u00edpadech, ale nechr\u00e1n\u00ed p\u0159ed v\u0161emi mo\u017en\u00fdmi varianty \u00fatoku. Nej\u00fa\u010dinn\u011bj\u0161\u00edm metodou ochrany z\u016fst\u00e1v\u00e1 pou\u017eit\u00ed pam\u011bti s k\u00f3dy pro opravu chyb (ECC), kter\u00e9 zna\u010dn\u011b zt\u011b\u017euj\u00ed, ale zcela nevylu\u010duj\u00ed prov\u00e1d\u011bn\u00ed \u00fatok\u016f t\u0159\u00eddy RowHammer. Sn\u00ed\u017een\u00ed pravd\u011bpodobnosti \u00fasp\u011b\u0161n\u00e9ho \u00fatoku tak\u00e9 umo\u017e\u0148uje zv\u00fd\u0161en\u00ed frekvence regenerace pam\u011bti. <\/p>\n

Spole\u010dnost AMD zve\u0159ejnila zpr\u00e1vu o probl\u00e9mu, ve kter\u00e9 uv\u00e1d\u00ed, \u017ee v procesorech AMD jsou pou\u017eity pam\u011b\u0165ov\u00e9 kontrol\u00e9ry vyhovuj\u00edc\u00ed specifikac\u00edm DDR, a proto\u017ee \u00fasp\u011b\u0161nost \u00fatoku z\u00e1vis\u00ed p\u0159edev\u0161\u00edm na nastaven\u00ed syst\u00e9mu a pam\u011bti DRAM, je nutn\u00e9 se na v\u00fdrobce pam\u011bti a syst\u00e9m\u016f obr\u00e1tit s dotazy t\u00fdkaj\u00edc\u00edmi se odstran\u011bn\u00ed probl\u00e9mu. Mezi st\u00e1vaj\u00edc\u00edmi zp\u016fsoby, jak zt\u00ed\u017eit proveden\u00ed \u00fatok\u016f t\u0159\u00eddy Rowhammer, se zmi\u0148uje pou\u017eit\u00ed ECC-pam\u011bti, zv\u00fd\u0161en\u00ed frekvence regenerace pam\u011bti, vypnut\u00ed re\u017eimu odlo\u017een\u00e9 regenerace a pou\u017eit\u00ed procesor\u016f s kontrol\u00e9ry podporuj\u00edc\u00edmi re\u017eim MAC (Maximum Activate Count) pro DDR4 (1., 2. a 3. generace AMD EPYC \u201eNaple\u201c, \u201eRome\u201c a \u201eMilan\u201c) a RFM (Refresh Management) pro DDR5 (4. generace AMD EPYC).
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0418\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0438 \u0438\u0437 \u0428\u0432\u0435\u0439\u0446\u0430\u0440\u0441\u043a\u043e\u0439 \u0432\u044b\u0441\u0448\u0435\u0439 \u0442\u0435\u0445\u043d\u0438\u0447\u0435\u0441\u043a\u043e\u0439 \u0448\u043a\u043e\u043b\u044b \u0426\u044e\u0440\u0438\u0445\u0430 \u0440\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0430\u043b\u0438 \u043c\u0435\u0442\u043e\u0434 \u0430\u0442\u0430\u043a\u0438 ZenHammer, \u043f\u0440\u0435\u0434\u0441\u0442\u0430\u0432\u043b\u044f\u044e\u0449\u0438\u0439 \u0441\u043e\u0431\u043e\u0439 \u0432\u0430\u0440\u0438\u0430\u043d\u0442 \u0430\u0442\u0430\u043a \u043a\u043b\u0430\u0441\u0441\u0430 RowHammer \u0434\u043b\u044f \u0438\u0437\u043c\u0435\u043d\u0435\u043d\u0438\u044f \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u043c\u043e\u0433\u043e \u043e\u0442\u0434\u0435\u043b\u044c\u043d\u044b\u0445 \u0431\u0438\u0442\u043e\u0432 \u0434\u0438\u043d\u0430\u043c\u0438\u0447\u0435\u0441\u043a\u043e\u0439 \u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u043e\u0439 \u043f\u0430\u043c\u044f\u0442\u0438 (DRAM), \u0430\u0434\u0430\u043f\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0439 \u0434\u043b\u044f \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u043d\u0430 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u0430\u0445 \u0441 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u0430\u043c\u0438 AMD. \u041f\u0440\u043e\u0448\u043b\u044b\u0435 \u043c\u0435\u0442\u043e\u0434\u044b \u0430\u0442\u0430\u043a \u043a\u043b\u0430\u0441\u0441\u0430 RowHammer \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0438\u0432\u0430\u043b\u0438\u0441\u044c \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u043c\u0438 \u043d\u0430 \u0431\u0430\u0437\u0435 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u043e\u0440\u043e\u0432 Intel, \u043d\u043e \u043f\u0440\u043e\u0432\u0435\u0434\u0451\u043d\u043d\u043e\u0435 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u043d\u0438\u0435 \u043f\u043e\u043a\u0430\u0437\u0430\u043b\u043e, \u0447\u0442\u043e \u0438\u0441\u043a\u0430\u0436\u0435\u043d\u0438\u044f \u044f\u0447\u0435\u0435\u043a \u043f\u0430\u043c\u044f\u0442\u0438 \u0442\u0430\u043a\u0436\u0435 \u043c\u043e\u0436\u043d\u043e […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":114582,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-114581","post","type-post","status-publish","format-standard","has-post-thumbnail","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\udd47ZenHammer \u2014 metoda \u00fatoku pro po\u0161kozen\u00ed obsahu pam\u011bti na platform\u00e1ch AMD Zen | ProHoster","description":"V\u00fdzkumn\u00edci z ETH Z\u00fcrich vyvinuli metodu \u00fatoku ZenHammer, kter\u00e1 p\u0159edstavuje variantu \u00fatok\u016f typu RowHammer pro zm\u011bnu obsahu jednotliv\u00fdch bit\u016f dynamick\u00e9 opera\u010dn\u00ed 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