{"id":115101,"date":"2024-04-16T14:30:16","date_gmt":"2024-04-16T12:30:16","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-putty-pozvolyayushhaya-vosstanovit-zakrytyj-klyuch-polzovatelya"},"modified":"2024-04-16T14:30:16","modified_gmt":"2024-04-16T12:30:16","slug":"uyazvimost-v-putty-pozvolyayushhaya-vosstanovit-zakrytyj-klyuch-polzovatelya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-putty-pozvolyayushhaya-vosstanovit-zakrytyj-klyuch-polzovatelya","title":{"rendered":"Zranitelnost v PuTTY umo\u017e\u0148uj\u00edc\u00ed obnoven\u00ed uzav\u0159en\u00e9ho u\u017eivatelsk\u00e9ho kl\u00ed\u010de","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V PuTTY, popul\u00e1rn\u00edm SSH klientu pro platformu Windows, byla odhalena z\u00e1va\u017en\u00e1 zranitelnost (CVE-2024-31497), kter\u00e1 umo\u017e\u0148uje obnovit priv\u00e1tn\u00ed kl\u00ed\u010d u\u017eivatele vygenerovan\u00fd pomoc\u00ed algoritmu ECDSA s eliptickou k\u0159ivkou NIST P-521 (ecdsa-sha2-nistp521). K odhalen\u00ed priv\u00e1tn\u00edho kl\u00ed\u010de sta\u010d\u00ed analyzovat p\u0159ibli\u017en\u011b 60 digit\u00e1ln\u00edch podpis\u016f vytvo\u0159en\u00fdch probl\u00e9mov\u00fdm kl\u00ed\u010dem. <\/p>\n

Zranitelnost se projevuje od verze PuTTY 0.68 a tak\u00e9 postihuje produkty, kter\u00e9 obsahuj\u00ed zraniteln\u00e9 verze PuTTY, jako nap\u0159\u00edklad FileZilla (3.24.1 \u2013 3.66.5), WinSCP (5.9.5 \u2013 6.3.2), TortoiseGit (2.4.0.2 \u2013 2.15.0) a TortoiseSVN (1.10.0 \u2013 1.14.6). Probl\u00e9m byl vy\u0159e\u0161en v aktualizac\u00edch PuTTY 0.81, FileZilla 3.67.0, WinSCP 6.3.3 a TortoiseGit 2.15.0.1. Po instalaci aktualizace se u\u017eivatel\u016fm doporu\u010duje vygenerovat nov\u00e9 kl\u00ed\u010de a odstranit star\u00e9 ve\u0159ejn\u00e9 kl\u00ed\u010de z files authorized_keys. <\/p>\n

Zranitelnost byla zp\u016fsobena nedbalost\u00ed v\u00fdvoj\u00e1\u0159\u016f, kte\u0159\u00ed p\u0159i generov\u00e1n\u00ed 521bitov\u00e9ho kl\u00ed\u010de pou\u017eili inicializa\u010dn\u00ed vektor (nonce) zalo\u017een\u00fd na 512bitov\u00e9 n\u00e1hodn\u00e9 sekvenci, pravd\u011bpodobn\u011b si mysleli, \u017ee 512 bit\u016f entropie je dostate\u010dn\u00e9 a zb\u00fdvaj\u00edc\u00edch 9 bit\u016f nem\u00e1 z\u00e1sadn\u00ed v\u00fdznam. V d\u016fsledku toho u v\u0161ech priv\u00e1tn\u00edch kl\u00ed\u010d\u016f vytv\u00e1\u0159en\u00fdch v PuTTY pomoc\u00ed algoritmu ecdsa-sha2-nistp521 prvn\u00edch 9 bit\u016f inicializa\u010dn\u00edho vektoru v\u017edy m\u011blo hodnotu nula. <\/p>\n

Pro ECDSA a DSA je d\u016fle\u017eit\u00e1 kvalita gener\u00e1toru pseudon\u00e1hodn\u00fdch \u010d\u00edsel a \u00fapln\u00e9 pokryt\u00ed n\u00e1hodn\u00fdmi daty parametru pou\u017e\u00edvan\u00e9ho p\u0159i v\u00fdpo\u010dtu modulu, proto\u017ee ur\u010den\u00ed i n\u011bkolika bit\u016f s informacemi o inicializa\u010dn\u00edm vektoru je dostate\u010dn\u00e9 pro proveden\u00ed \u00fatoku na sekven\u010dn\u00ed obnovu cel\u00e9ho priv\u00e1tn\u00edho kl\u00ed\u010de. Pro \u00fasp\u011b\u0161nou obnovu kl\u00ed\u010de sta\u010d\u00ed m\u00edt ve\u0159ejn\u00fd kl\u00ed\u010d a analyzovat n\u011bkolik des\u00edtek digit\u00e1ln\u00edch podpis\u016f generovan\u00fdch pomoc\u00ed problematick\u00e9ho kl\u00ed\u010de pro zn\u00e1m\u00e9 \u00fato\u010dn\u00edkovi \u00fadaje. \u00datok se redukuje na \u0159e\u0161en\u00ed \u00falohy HNP (Hidden Number Problem). <\/p>\n

Pot\u0159ebn\u00e9 digit\u00e1ln\u00ed podpisy lze z\u00edskat nap\u0159\u00edklad p\u0159ipojen\u00edm u\u017eivatele k \u00fato\u010dn\u00edkov\u011b SSH serveru nebo k Git serveru, kter\u00fd pou\u017e\u00edv\u00e1 SSH jako transport. Pot\u0159ebn\u00e9 podpisy pro \u00fatok lze tak\u00e9 zjistit, pokud byl kl\u00ed\u010d pou\u017eit k podepisov\u00e1n\u00ed libovoln\u00fdch dat, nap\u0159\u00edklad git commit\u016f p\u0159i pou\u017e\u00edv\u00e1n\u00ed SSH agenta Pageant pro p\u0159esm\u011brov\u00e1n\u00ed provozu na v\u00fdvoj\u00e1\u0159sk\u00fd hostitel. Z\u00edsk\u00e1n\u00ed pot\u0159ebn\u00fdch dat pro obnoven\u00ed kl\u00ed\u010de b\u011bhem MITM \u00fatoku je vylou\u010deno, proto\u017ee podpisy v SSH nejsou p\u0159en\u00e1\u0161eny v otev\u0159en\u00e9 podob\u011b. <\/p>\n

Je zaznamen\u00e1no, \u017ee podobn\u00e9 vyu\u017eit\u00ed ne\u00fapln\u00fdch inicia\u010dn\u00edch vektor\u016f bylo pou\u017eito v PuTTY a pro dal\u0161\u00ed druhy eliptick\u00fdch k\u0159ivek, ale pro algoritmy odli\u0161n\u00e9 od ECDSA P-521 nebylo \u00fanik\u016f informac\u00ed dost pro proveden\u00ed funk\u010dn\u00edho \u00fatoku na obnovu kl\u00ed\u010de. Kl\u00ed\u010de ECDSA jin\u00e9 velikosti a kl\u00ed\u010de Ed25519 \u00fatoku nepodl\u00e9haj\u00ed.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 PuTTY, \u043a\u043b\u0438\u0435\u043d\u0442\u0435 \u0434\u043b\u044f \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 SSH, \u043f\u043e\u043b\u044c\u0437\u0443\u044e\u0449\u0435\u0433\u043e\u0441\u044f \u043f\u043e\u043f\u0443\u043b\u044f\u0440\u043d\u043e\u0441\u0442\u044c\u044e \u043d\u0430 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u0435 Windows, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u043e\u043f\u0430\u0441\u043d\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2024-31497), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u043e\u0441\u0441\u043e\u0437\u0434\u0430\u0442\u044c \u0437\u0430\u043a\u0440\u044b\u0442\u044b\u0439 \u043a\u043b\u044e\u0447 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044f, \u0441\u0433\u0435\u043d\u0435\u0440\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0439 \u0441 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435\u043c \u0430\u043b\u0433\u043e\u0440\u0438\u0442\u043c\u0430 ECDSA \u0441 \u044d\u043b\u043b\u0438\u043f\u0442\u0438\u0447\u0435\u0441\u043a\u043e\u0439 \u043a\u0440\u0438\u0432\u043e\u0439 NIST P-521 (ecdsa-sha2-nistp521). \u0414\u043b\u044f \u043f\u043e\u0434\u0431\u043e\u0440\u0430 \u0437\u0430\u043a\u0440\u044b\u0442\u043e\u0433\u043e \u043a\u043b\u044e\u0447\u0430 \u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e \u043f\u0440\u043e\u0430\u043d\u0430\u043b\u0438\u0437\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u043f\u0440\u0438\u043c\u0435\u0440\u043d\u043e 60 \u0446\u0438\u0444\u0440\u043e\u0432\u044b\u0445 \u043f\u043e\u0434\u043f\u0438\u0441\u0435\u0439, \u0441\u0444\u043e\u0440\u043c\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u044b\u0445 \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u043d\u044b\u043c \u043a\u043b\u044e\u0447\u043e\u043c. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u043d\u0430\u0447\u0438\u043d\u0430\u044f \u0441 \u0432\u0435\u0440\u0441\u0438\u0438 PuTTY 0.68 \u0438 \u0442\u0430\u043a\u0436\u0435 \u0437\u0430\u0442\u0440\u043e\u043d\u0443\u043b\u0430 \u043f\u0440\u043e\u0434\u0443\u043a\u0442\u044b, […]<\/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-115101","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 PuTTY, kter\u00e1 umo\u017e\u0148uje obnovit soukrom\u00fd kl\u00ed\u010d u\u017eivatele | ProHoster","description":"V PuTTY, popul\u00e1rn\u00edm SSH klientu na platform\u011b Windows, byla odhalena z\u00e1va\u017en\u00e1 zranitelnost (CVE-2024-31497), kter\u00e1 umo\u017e\u0148uje rekonstrukci u\u017eivatelsk\u00e9ho soukrom\u00e9ho kl\u00ed\u010de generovan\u00e9ho pomoc\u00ed.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/uyazvimost-v-putty-pozvolyayushhaya-vosstanovit-zakrytyj-klyuch-polzovatelya","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\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0432 PuTTY, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u043e\u0441\u0441\u0442\u0430\u043d\u043e\u0432\u0438\u0442\u044c \u0437\u0430\u043a\u0440\u044b\u0442\u044b\u0439 \u043a\u043b\u044e\u0447 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044f | ProHoster","og:description":"\u0412 PuTTY, \u043a\u043b\u0438\u0435\u043d\u0442\u0435 \u0434\u043b\u044f \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 SSH, \u043f\u043e\u043b\u044c\u0437\u0443\u044e\u0449\u0435\u0433\u043e\u0441\u044f \u043f\u043e\u043f\u0443\u043b\u044f\u0440\u043d\u043e\u0441\u0442\u044c\u044e \u043d\u0430 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u0435 Windows, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u043e\u043f\u0430\u0441\u043d\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2024-31497), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u043e\u0441\u0441\u043e\u0437\u0434\u0430\u0442\u044c \u0437\u0430\u043a\u0440\u044b\u0442\u044b\u0439 \u043a\u043b\u044e\u0447 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