{"id":111506,"date":"2023-11-14T21:10:14","date_gmt":"2023-11-14T19:10:14","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/vossozdanie-rsa-klyuchej-cherez-analiz-ssh-soedinenij-k-sbojnym-serveram"},"modified":"2023-11-14T21:10:14","modified_gmt":"2023-11-14T19:10:14","slug":"vossozdanie-rsa-klyuchej-cherez-analiz-ssh-soedinenij-k-sbojnym-serveram","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/vossozdanie-rsa-klyuchej-cherez-analiz-ssh-soedinenij-k-sbojnym-serveram","title":{"rendered":"Obnoven\u00ed RSA kl\u00ed\u010d\u016f anal\u00fdzou SSH spojen\u00ed k selh\u00e1vaj\u00edc\u00edm server\u016fm","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Skupina v\u00fdzkumn\u00edk\u016f z Kalifornsk\u00e9 univerzity v San Diegu demonstrovala mo\u017enost obnoven\u00ed soukrom\u00fdch hostitelsk\u00fdch RSA kl\u00ed\u010d\u016f SSH serveru pomoc\u00ed pasivn\u00ed anal\u00fdzy SSH provozu. \u00datok m\u016f\u017ee b\u00fdt proveden na serverech, kde v d\u016fsledku n\u00e1hodn\u00fdch okolnost\u00ed nebo akc\u00ed \u00fato\u010dn\u00edka doch\u00e1z\u00ed k selh\u00e1n\u00ed b\u011bhem v\u00fdpo\u010dtu digit\u00e1ln\u00edho podpisu p\u0159i ustanoven\u00ed SSH spojen\u00ed. Selh\u00e1n\u00ed mohou b\u00fdt jak softwarov\u00e1 (nespr\u00e1vn\u00e9 prov\u00e1d\u011bn\u00ed matematick\u00fdch operac\u00ed, porucha pam\u011bti), tak hardwarov\u00e1 (chyby p\u0159i pr\u00e1ci NVRAM a DRAM nebo selh\u00e1n\u00ed p\u0159i v\u00fdpadc\u00edch nap\u00e1jen\u00ed). <\/p>\n

Jedn\u00edm z mo\u017enost\u00ed vyvol\u00e1n\u00ed selh\u00e1n\u00ed mohou b\u00fdt \u00fatoky t\u0159\u00eddy RowHammer, kter\u00e9 mimo jin\u00e9 umo\u017e\u0148uj\u00ed na d\u00e1lku nebo p\u0159i zpracov\u00e1n\u00ed JavaScriptov\u00e9ho k\u00f3du v prohl\u00ed\u017ee\u010di dos\u00e1hnout zkreslen\u00ed obsahu jednotliv\u00fdch bit\u016f pam\u011bti p\u0159i intenzivn\u00edm cyklick\u00e9m \u010dten\u00ed dat z sousedn\u00edch pam\u011b\u0165ov\u00fdch bun\u011bk. Dal\u0161\u00ed variantou vyvol\u00e1n\u00ed selh\u00e1n\u00ed m\u016f\u017ee b\u00fdt zneu\u017eit\u00ed zranitelnost\u00ed vedouc\u00edch k p\u0159ete\u010den\u00ed vyrovn\u00e1vac\u00ed pam\u011bti a po\u0161kozen\u00ed dat s kl\u00ed\u010di v pam\u011bti. <\/p>\n

Ve zve\u0159ejn\u011bn\u00e9m v\u00fdzkumu bylo prok\u00e1z\u00e1no, \u017ee p\u0159i pou\u017eit\u00ed digit\u00e1ln\u00edch podpis\u016f v SSH na b\u00e1zi algoritmu RSA jsou parametry digit\u00e1ln\u00edho podpisu n\u00e1chyln\u00e9 k \u00fatok\u016fm na obnovu soukrom\u00fdch RSA kl\u00ed\u010d\u016f metodou Lattice (Fault Attack) v p\u0159\u00edpad\u011b, \u017ee dojde k softwarov\u00fdm nebo hardwarov\u00fdm selh\u00e1n\u00edm b\u011bhem procesu v\u00fdpo\u010dtu podpisu. Podstatou t\u00e9to metody je porovnat spr\u00e1vn\u00e9 a selhan\u00e9 digit\u00e1ln\u00ed podpisy RSA, co\u017e umo\u017e\u0148uje ur\u010dit nejv\u011bt\u0161\u00ed spole\u010dn\u00fd d\u011blitel pro z\u00edsk\u00e1n\u00ed jednoho z prvo\u010d\u00edsel pou\u017eit\u00fdch p\u0159i formov\u00e1n\u00ed kl\u00ed\u010de. <\/p>\n

Z\u00e1kladem \u0161ifrov\u00e1n\u00ed RSA je operace umocn\u011bn\u00ed modulo velk\u00e9ho \u010d\u00edsla. V ve\u0159ejn\u00e9m kl\u00ed\u010di se nach\u00e1z\u00ed modul a exponent. Modul se tvo\u0159\u00ed na z\u00e1klad\u011b dvou n\u00e1hodn\u00fdch prvo\u010d\u00edsel, kter\u00e1 jsou zn\u00e1ma pouze majiteli soukrom\u00e9ho kl\u00ed\u010de. \u00datok m\u016f\u017ee b\u00fdt aplikov\u00e1n na implementace RSA, kter\u00e9 pou\u017e\u00edvaj\u00ed \u010c\u00ednskou teorii zbytk\u016f a deterministick\u00e9 sch\u00e9ma dopl\u0148kov\u00e9ho v\u00fdpln\u011b, jako je PKCS#1 v1.5. <\/p>\n

K proveden\u00ed \u00fatoku sta\u010d\u00ed pasivn\u00ed sledov\u00e1n\u00ed legitimn\u00edch p\u0159ipojen\u00ed k SSH serveru, dokud se neobjev\u00ed v provozu z\u00e1vadn\u00fd digit\u00e1ln\u00ed podpis, kter\u00fd lze pou\u017e\u00edt jako zdroj informac\u00ed pro rekonstrukci soukrom\u00e9ho RSA kl\u00ed\u010de. Po rekonstrukci hostitelsk\u00e9ho RSA kl\u00ed\u010de m\u016f\u017ee \u00fato\u010dn\u00edk b\u011bhem MITM \u00fatoku nen\u00e1padn\u011b p\u0159esm\u011brovat po\u017eadavky na fale\u0161n\u00fd host, kter\u00fd se vyd\u00e1v\u00e1 za kompromitovan\u00fd SSH server, a zorganizovat odposlech p\u0159ed\u00e1van\u00fdch dat. server<\/a> dat. <\/p>\n

Studium sb\u00edrky odposlechnut\u00fdch s\u00ed\u0165ov\u00fdch dat, zahrnuj\u00edc\u00ed p\u0159ibli\u017en\u011b 5,2 miliardy z\u00e1znam\u016f spojen\u00fdch s pou\u017e\u00edv\u00e1n\u00edm protokolu SSH, odhalilo p\u0159ibli\u017en\u011b 3,2 miliardy otev\u0159en\u00fdch hostitelsk\u00fdch kl\u00ed\u010d\u016f a digit\u00e1ln\u00edch podpis\u016f pou\u017e\u00edvan\u00fdch b\u011bhem vyjedn\u00e1v\u00e1n\u00ed SSH relac\u00ed. Z nich bylo 1,2 miliardy (39,1 %) vytvo\u0159eno pomoc\u00ed algoritmu RSA. V 593671 p\u0159\u00edpadech (0,048 %) byla RSA podpis po\u0161kozen a nepro\u0161el kontrolou. U 4962 vadn\u00fdch podpis\u016f se poda\u0159ilo aplikovat metodu faktorizace m\u0159\u00ed\u017eky k ur\u010den\u00ed soukrom\u00e9ho kl\u00ed\u010de na z\u00e1klad\u011b zn\u00e1m\u00e9ho ve\u0159ejn\u00e9ho kl\u00ed\u010de, co\u017e nakonec umo\u017enilo zrekonstruovat 189 unik\u00e1tn\u00edch p\u00e1r\u016f RSA kl\u00ed\u010d\u016f (v mnoha p\u0159\u00edpadech byly pro generov\u00e1n\u00ed r\u016fzn\u00fdch po\u0161kozen\u00fdch podpis\u016f pou\u017eity stejn\u00e9 kl\u00ed\u010de a vadn\u00e1 za\u0159\u00edzen\u00ed). Rekonstrukce kl\u00ed\u010d\u016f trvala p\u0159ibli\u017en\u011b 26 hodin procesorov\u00e9ho \u010dasu.

\"Obnoven\u00ed<\/center> <\/p>\n

Probl\u00e9m se t\u00fdk\u00e1 pouze specifick\u00fdch implementac\u00ed protokolu SSH, kter\u00e9 se p\u0159ev\u00e1\u017en\u011b pou\u017e\u00edvaj\u00ed na vestav\u011bn\u00fdch za\u0159\u00edzen\u00edch. Jako p\u0159\u00edklady za\u0159\u00edzen\u00ed s problematick\u00fdmi implementacemi SSH byly zm\u00edn\u011bny produkty Zyxel, Cisco, Mocana a Hillstone Networks. OpenSSH nen\u00ed na tuto problematiku n\u00e1chyln\u00fd, proto\u017ee p\u0159i generov\u00e1n\u00ed kl\u00ed\u010d\u016f pou\u017e\u00edv\u00e1 knihovnu OpenSSL (nebo LibreSSL), kter\u00e1 obsahuje ochranu proti \u00fatok\u016fm zalo\u017een\u00fdm na anal\u00fdze z\u00e1vad (Fault Attack) od roku 2001. Krom\u011b toho byla v OpenSSH sch\u00e9ma digit\u00e1ln\u00edch podpis\u016f ssh-rsa (na b\u00e1zi sha1) od roku 2020 prohl\u00e1\u0161ena za zastaralou a byla vypnuta ve verzi 8.8 (podpora sch\u00e9mat rsa-sha2-256 a rsa-sha2-512 z\u016fst\u00e1v\u00e1). Potenci\u00e1ln\u011b by \u00fatok mohl b\u00fdt aplikovateln\u00fd i na protokol IPsec, ale v\u00fdzkumn\u00edci nem\u011bli dostate\u010dn\u00e1 experiment\u00e1ln\u00ed data pro potvrzen\u00ed takov\u00e9ho \u00fatoku v praxi.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0413\u0440\u0443\u043f\u043f\u0430 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439 \u0438\u0437 \u041a\u0430\u043b\u0438\u0444\u043e\u0440\u043d\u0438\u0439\u0441\u043a\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0432 \u0421\u0430\u043d-\u0414\u0438\u0435\u0433\u043e \u043f\u0440\u043e\u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043b\u0430 \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c \u0432\u043e\u0441\u0441\u043e\u0437\u0434\u0430\u043d\u0438\u044f \u0437\u0430\u043a\u0440\u044b\u0442\u044b\u0445 \u0445\u043e\u0441\u0442\u043e\u0432\u044b\u0445 RSA-\u043a\u043b\u044e\u0447\u0435\u0439 SSH-\u0441\u0435\u0440\u0432\u0435\u0440\u0430, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044f \u043f\u0430\u0441\u0441\u0438\u0432\u043d\u044b\u0439 \u0430\u043d\u0430\u043b\u0438\u0437 \u0442\u0440\u0430\u0444\u0438\u043a\u0430 SSH. \u0410\u0442\u0430\u043a\u0430 \u043c\u043e\u0436\u0435\u0442 \u0431\u044b\u0442\u044c \u0441\u043e\u0432\u0435\u0440\u0448\u0435\u043d\u0430 \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440\u044b, \u043d\u0430 \u043a\u043e\u0442\u043e\u0440\u044b\u0445 \u0432 \u0441\u0438\u043b\u0443 \u0441\u0442\u0435\u0447\u0435\u043d\u0438\u044f \u043e\u0431\u0441\u0442\u043e\u044f\u0442\u0435\u043b\u044c\u0441\u0442\u0432 \u0438\u043b\u0438 \u0434\u0435\u0439\u0441\u0442\u0432\u0438\u0439 \u0430\u0442\u0430\u043a\u0443\u044e\u0449\u0435\u0433\u043e \u0432\u043e\u0437\u043d\u0438\u043a\u0430\u044e\u0442 \u0441\u0431\u043e\u0438 \u0432\u043e \u0432\u0440\u0435\u043c\u044f \u0432\u044b\u0447\u0438\u0441\u043b\u0435\u043d\u0438\u044f \u0446\u0438\u0444\u0440\u043e\u0432\u043e\u0439 \u043f\u043e\u0434\u043f\u0438\u0441\u0438 \u043f\u0440\u0438 \u0443\u0441\u0442\u0430\u043d\u043e\u0432\u043a\u0435 SSH-\u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u044f. \u0421\u0431\u043e\u0438 \u043c\u043e\u0433\u0443\u0442 \u0431\u044b\u0442\u044c \u043a\u0430\u043a \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u044b\u043c\u0438 (\u043d\u0435\u043a\u043e\u0440\u0440\u0435\u043a\u0442\u043d\u043e\u0435 \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435 \u043c\u0430\u0442\u0435\u043c\u0430\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0445 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u0439, \u043f\u043e\u0432\u0440\u0435\u0436\u0434\u0435\u043d\u0438\u0435 \u043f\u0430\u043c\u044f\u0442\u0438), […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":111507,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-111506","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\udd47Rekonstrukce RSA kl\u00ed\u010d\u016f anal\u00fdzou SSH spojen\u00ed k nefunk\u010dn\u00edm server\u016fm | ProHoster","description":"Skupina v\u00fdzkumn\u00edk\u016f z Kalifornsk\u00e9 univerzity v San Diegu demonstrovala mo\u017enost rekonstrukce uzav\u0159en\u00fdch hostitelsk\u00fdch RSA kl\u00ed\u010d\u016f SSH serveru pomoc\u00ed pasivn\u00ed anal\u00fdzy SSH provozu.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/vossozdanie-rsa-klyuchej-cherez-analiz-ssh-soedinenij-k-sbojnym-serveram","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","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\u043e\u0441\u0441\u043e\u0437\u0434\u0430\u043d\u0438\u0435 RSA-\u043a\u043b\u044e\u0447\u0435\u0439 \u0447\u0435\u0440\u0435\u0437 \u0430\u043d\u0430\u043b\u0438\u0437 SSH-\u0441\u043e\u0435\u0434\u0438\u043d\u0435\u043d\u0438\u0439 \u043a \u0441\u0431\u043e\u0439\u043d\u044b\u043c \u0441\u0435\u0440\u0432\u0435\u0440\u0430\u043c | ProHoster","og:description":"\u0413\u0440\u0443\u043f\u043f\u0430 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u0435\u0439 \u0438\u0437 \u041a\u0430\u043b\u0438\u0444\u043e\u0440\u043d\u0438\u0439\u0441\u043a\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0432 \u0421\u0430\u043d-\u0414\u0438\u0435\u0433\u043e \u043f\u0440\u043e\u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043b\u0430 \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044c \u0432\u043e\u0441\u0441\u043e\u0437\u0434\u0430\u043d\u0438\u044f \u0437\u0430\u043a\u0440\u044b\u0442\u044b\u0445 \u0445\u043e\u0441\u0442\u043e\u0432\u044b\u0445 RSA-\u043a\u043b\u044e\u0447\u0435\u0439 SSH-\u0441\u0435\u0440\u0432\u0435\u0440\u0430, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044f \u043f\u0430\u0441\u0441\u0438\u0432\u043d\u044b\u0439 \u0430\u043d\u0430\u043b\u0438\u0437 \u0442\u0440\u0430\u0444\u0438\u043a\u0430 SSH.","og:url":"https:\/\/prohoster.info\/cs\/blog\/news\/vossozdanie-rsa-klyuchej-cherez-analiz-ssh-soedinenij-k-sbojnym-serveram","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":"2023-11-14T19:10:14+00:00","article:modified_time":"2023-11-14T19:10:14+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\/cs\/wp-json\/wp\/v2\/posts\/111506","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/comments?post=111506"}],"version-history":[{"count":1,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/111506\/revisions"}],"predecessor-version":[{"id":173001,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/posts\/111506\/revisions\/173001"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media\/111507"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/media?parent=111506"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/categories?post=111506"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/cs\/wp-json\/wp\/v2\/tags?post=111506"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}