K dispoz\u00edcii je opravn\u00fd bal\u00edk OpenSSH 9.9p2, v ktorom boli odstr\u00e1nen\u00e9 dve zranite\u013enosti zisten\u00e9 spolo\u010dnos\u0165ou Qualys. Bol demon\u0161trovan\u00fd pr\u00edklad vyu\u017eitia t\u00fdchto zranite\u013enost\u00ed na uskuto\u010dnenie \u00fatoku MITM, ktor\u00fd umo\u017e\u0148uje pri pokuse klienta o pripojenie k SSH serveru presmerova\u0165 prev\u00e1dzku na svoj falo\u0161n\u00fd server, ob\u00eds\u0165 overenie hostite\u013esk\u00fdch k\u013e\u00fa\u010dov a vytvori\u0165 u klienta dojem, \u017ee sa pripojuje k \u017eiadan\u00e9mu serveru (ssh klient prijme hostite\u013esk\u00fd k\u013e\u00fa\u010d falo\u0161n\u00e9ho servera namiesto k\u013e\u00fa\u010da legit\u00edmneho servera). <\/p>\n
Prv\u00e1 zranite\u013enos\u0165 (CVE-2025-26465) je sp\u00f4soben\u00e1 logickou chybou v utilite ssh, ktor\u00e1 umo\u017e\u0148uje ob\u00eds\u0165 overenie identity servera a vykona\u0165 \u00fatok MITM. Probl\u00e9m sa prejavuje od vydania OpenSSH 6.8p1 (december 2014) v konfigur\u00e1ci\u00e1ch s aktivovanou nastaven\u00edm VerifyHostKeyDNS. V z\u00e1kladnej dod\u00e1vke OpenSSH je t\u00e1to mo\u017enos\u0165 predvolene vypnut\u00e1, ale do marca 2023 bola zapnut\u00e1 v nastaveniach ssh vo FreeBSD. <\/p>\n
Podstata probl\u00e9mu spo\u010d\u00edva v tom, \u017ee v k\u00f3de funkcie verify_host_key_callback() sa pri volan\u00ed funkcie verify_host_key() kontroluje iba k\u00f3d chyby «-1», zatia\u013e \u010do in\u00e9 k\u00f3dy, ako napr\u00edklad «-2», s\u00fa ignorovan\u00e9. V d\u00f4sledku toho m\u00f4\u017ee funkcia verify_host_key_callback() vr\u00e1ti\u0165 \u00faspe\u0161n\u00fd k\u00f3d «0», napriek tomu, \u017ee funkcia verify_host_key() vr\u00e1tila chybu «-2». K\u00f3d chyby «-2» sa vracia funkciou verify_host_key() pri nedostatku pam\u00e4te. Ak sa vytvoria podmienky, ktor\u00e9 zabr\u00e1nia prideleniu pam\u00e4te vo funkcii verify_host_key(), SSH predpoklad\u00e1, \u017ee hostite\u013esk\u00fd k\u013e\u00fa\u010d bol \u00faspe\u0161ne overen\u00fd. Na vytvorenie tak\u00fdchto podmienok falo\u0161n\u00fd SSH server \u00fato\u010dn\u00edka, na ktor\u00fd je z\u00e1kazn\u00edk presmerovan\u00fd, vracia hostite\u013esk\u00fd k\u013e\u00fa\u010d maxim\u00e1lnej mo\u017enej ve\u013ekosti (256KB) a z\u00e1rove\u0148 sa zneu\u017e\u00edva \u00fanik pam\u00e4te na strane ssh klienta. <\/p>\n
Podmienky na vytvorenie \u00faniku pam\u00e4te sa dosahuj\u00fa druhou zranite\u013enos\u0165ou (CVE-2025-26466), ktor\u00e1 sa t\u00fdka ako klienta ssh, tak aj server<\/a> sshd, a je zneu\u017e\u00edvan\u00fd bez autentifik\u00e1cie. Zranite\u013enos\u0165 umo\u017e\u0148uje vy\u010derpanie dostupnej pam\u00e4te procesu a vytvorenie vysokej z\u00e1\u0165a\u017ee na CPU prostredn\u00edctvom odosielania ve\u013ek\u00e9ho po\u010dtu paketov SSH2_MSG_PING. V spracovate\u013eovi paketov SSH2_MSG_PING existuje \u00fanik pam\u00e4te, ktor\u00fd sa prejavuje od vydania OpenSSH 9.5p1 (august 2023). \u00danik sa vyskytuje, preto\u017ee na ka\u017ed\u00fd prich\u00e1dzaj\u00faci 16-bajtov\u00fd PING paket sa prideli 256-bajtov\u00fd buffer na vytvorenie odpovede, ale tento buffer sa uvo\u013e\u0148uje a\u017e po ukon\u010den\u00ed dohodovania k\u013e\u00fa\u010dov. Ako obch\u00e1dzaj\u00face opatrenie na ochranu sa navrhuje nastavi\u0165 obmedzenia pomocou direkt\u00edv LoginGraceTime, MaxStartups a PerSourcePenalties. \u0414\u043e\u0441\u0442\u0443\u043f\u0435\u043d \u043a\u043e\u0440\u0440\u0435\u043a\u0442\u0438\u0440\u0443\u044e\u0449\u0438\u0439 \u0432\u044b\u043f\u0443\u0441\u043a OpenSSH 9.9p2, \u0432 \u043a\u043e\u0442\u043e\u0440\u043e\u043c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u044b \u0434\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u043d\u044b\u0435 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0435\u0439 Qualys. \u041f\u0440\u043e\u0434\u0435\u043c\u043e\u043d\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043d \u043f\u0440\u0438\u043c\u0435\u0440 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u0434\u0430\u043d\u043d\u044b\u0445 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 \u0434\u043b\u044f \u0441\u043e\u0432\u0435\u0440\u0448\u0435\u043d\u0438\u044f MITM-\u0430\u0442\u0430\u043a\u0438, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u043f\u0440\u0438 \u043f\u043e\u043f\u044b\u0442\u043a\u0435 \u043f\u043e\u0434\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u043a\u043b\u0438\u0435\u043d\u0442\u0430 \u043a SSH-\u0441\u0435\u0440\u0432\u0435\u0440\u0443, \u043f\u0435\u0440\u0435\u043d\u0430\u043f\u0440\u0430\u0432\u0438\u0442\u044c \u0442\u0440\u0430\u0444\u0438\u043a \u043d\u0430 \u0441\u043e\u0431\u0441\u0442\u0432\u0435\u043d\u043d\u044b\u0439 \u0444\u0438\u043a\u0442\u0438\u0432\u043d\u044b\u0439 \u0441\u0435\u0440\u0432\u0435\u0440, \u043e\u0431\u043e\u0439\u0442\u0438 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0443 \u0445\u043e\u0441\u0442\u043e\u0432\u044b\u0445 \u043a\u043b\u044e\u0447\u0435\u0439 \u0438 \u0441\u043e\u0437\u0434\u0430\u0442\u044c \u0443 \u043a\u043b\u0438\u0435\u043d\u0442\u0430 \u0432\u0438\u0434\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u0434\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u043a \u0436\u0435\u043b\u0430\u0435\u043c\u043e\u043c\u0443 \u0441\u0435\u0440\u0432\u0435\u0440\u0443 (ssh-\u043a\u043b\u0438\u0435\u043d\u0442 \u043f\u0440\u0438\u043c\u0435\u0442 \u0445\u043e\u0441\u0442\u043e\u0432\u044b\u0439 \u043a\u043b\u044e\u0447 \u0444\u0438\u043a\u0442\u0438\u0432\u043d\u043e\u0433\u043e \u0441\u0435\u0440\u0432\u0435\u0440\u0430 \u0432\u043c\u0435\u0441\u0442\u043e \u043a\u043b\u044e\u0447\u0430 […]<\/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-121998","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\udd47Aktualiz\u00e1cia OpenSSH 9.9p2 s odstr\u00e1nen\u00edm mo\u017enosti vykonania MITM \u00fatoku | ProHoster","description":"Dostupn\u00e1 je opravn\u00e1 verzia OpenSSH 9.9p2, v ktorej boli odstr\u00e1nen\u00e9 dve zranite\u013enosti zisten\u00e9 spolo\u010dnos\u0165ou Qualys.","canonical_url":"https:\/\/prohoster.info\/sk\/blog\/news\/obnovlenie-openssh-9-9p2-s-ustraneniem-vozmozhnosti-soversheniya-mitm-ataki","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"sk_SK","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\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 OpenSSH 9.9p2 \u0441 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0435\u043c \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u0438 \u0441\u043e\u0432\u0435\u0440\u0448\u0435\u043d\u0438\u044f MITM-\u0430\u0442\u0430\u043a\u0438 | ProHoster","og:description":"\u0414\u043e\u0441\u0442\u0443\u043f\u0435\u043d \u043a\u043e\u0440\u0440\u0435\u043a\u0442\u0438\u0440\u0443\u044e\u0449\u0438\u0439 \u0432\u044b\u043f\u0443\u0441\u043a OpenSSH 9.9p2, \u0432 \u043a\u043e\u0442\u043e\u0440\u043e\u043c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u044b \u0434\u0432\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u043d\u044b\u0435 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0435\u0439 Qualys.","og:url":"https:\/\/prohoster.info\/sk\/blog\/news\/obnovlenie-openssh-9-9p2-s-ustraneniem-vozmozhnosti-soversheniya-mitm-ataki","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":"2025-02-18T18:22:04+00:00","article:modified_time":"2025-02-18T18:22:04+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"121998","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":"2026-01-23 10:42:19","breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2026-01-23 10:42:19","updated":"2026-01-23 10:42:19","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/posts\/121998","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/comments?post=121998"}],"version-history":[{"count":1,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/posts\/121998\/revisions"}],"predecessor-version":[{"id":173038,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/posts\/121998\/revisions\/173038"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/media?parent=121998"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/categories?post=121998"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/sk\/wp-json\/wp\/v2\/tags?post=121998"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"