{"id":82460,"date":"2020-05-21T19:42:00","date_gmt":"2020-05-21T17:42:00","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/ataka-nxnsattack-zatragivayushhaya-vse-dns-rezolvery"},"modified":"2020-05-21T19:42:00","modified_gmt":"2020-05-21T17:42:00","slug":"ataka-nxnsattack-zatragivayushhaya-vse-dns-rezolvery","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/ataka-nxnsattack-zatragivayushhaya-vse-dns-rezolvery","title":{"rendered":"NXNSAttack t\u00e1mad\u00e1s, amely minden DNS-rezolvert \u00e9rint","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

A Tel-Aviv Egyetem \u00e9s a Herzl\u00edvai Interdiszciplin\u00e1ris K\u00f6zpont kutat\u00f3csoportja (Izrael) kifejlesztette<\/a><\/noindex> az \u00faj t\u00e1mad\u00e1si m\u00f3dszert NXNSAttack<\/a><\/noindex> (PDF<\/a><\/noindex>), amely lehet\u0151v\u00e9 teszi b\u00e1rmilyen DNS-rezolver \u00e1raml\u00e1s\u00e1nak fokoz\u00e1s\u00e1t, ak\u00e1r 1621-szeres fokoz\u00e1ssal a csomagok sz\u00e1m\u00e1ban (minden egyes, a rezolverhez k\u00fcld\u00f6tt k\u00e9r\u00e9s eset\u00e9n 1621 k\u00e9r\u00e9s k\u00fcldhet\u0151 a c\u00e9lkiszolg\u00e1l\u00f3hoz) \u00e9s ak\u00e1r 163-szoros fokoz\u00e1ssal a forgalomban. <\/p>\n

A probl\u00e9ma a protokoll m\u0171k\u00f6d\u00e9s\u00e9nek saj\u00e1toss\u00e1gaival kapcsolatos, \u00e9s minden DNS-szervert \u00e9rint, amely t\u00e1mogatja a rekurz\u00edv k\u00e9r\u00e9sfeldolgoz\u00e1st, bele\u00e9rtve a BIND<\/a><\/noindex> (CVE-2020-8616), Knot<\/a><\/noindex> (CVE-2020-12667), PowerDNS<\/a><\/noindex> (CVE-2020-10995), Windows DNS Szerver<\/a><\/noindex> \u00e9s Unbound<\/a><\/noindex> (CVE-2020-12662), valamint a Google, Cloudflare, Amazon, Quad9, ICANN \u00e9s m\u00e1s c\u00e9gek nyilv\u00e1nos DNS-szolg\u00e1ltat\u00e1sait. A probl\u00e9ma megold\u00e1s\u00e1t a DNS-szerverek fejleszt\u0151ivel koordin\u00e1lt\u00e1k, akik egyszerre adt\u00e1k ki az \u00e9rz\u00e9kenys\u00e9g kik\u00fcsz\u00f6b\u00f6l\u00e9s\u00e9vel kapcsolatos friss\u00edt\u00e9seket term\u00e9keikben. A t\u00e1mad\u00e1s ellen v\u00e9delmet ny\u00fajtanak a kiad\u00e1sok:
\nUnbound 1.10.1<\/a><\/noindex>, Knot Resolver 5.1.1<\/a><\/noindex>, PowerDNS Recursor 4.3.1, 4.2.2, 4.1.16<\/a><\/noindex>, BIND 9.11.19, 9.14.12, 9.16.3<\/a><\/noindex>.<\/p>\n

A t\u00e1mad\u00e1s alapja, hogy a t\u00e1mad\u00f3 olyan lek\u00e9rdez\u00e9seket haszn\u00e1l, amelyek nagy sz\u00e1m\u00fa kor\u00e1bban nem l\u00e1tott fikt\u00edv NS-rekordra hivatkoznak, amelyeknek deleg\u00e1lt n\u00e9vmeghat\u00e1roz\u00e1sukat kell v\u00e9gezni\u00fck, de a v\u00e1laszban nem szerepelnek a NS-szerverek IP-c\u00edm\u00e9r\u0151l sz\u00f3l\u00f3 glue-rekordok. P\u00e9ld\u00e1ul a t\u00e1mad\u00f3 k\u00e9rd\u00e9st k\u00fcld a sd1.attacker.com n\u00e9v meghat\u00e1roz\u00e1s\u00e1ra, mik\u00f6zben az attacker.com domain\u00e9rt felel\u0151s DNS-szervert ir\u00e1ny\u00edtja. Amikor a rezolver a t\u00e1mad\u00f3 DNS-szerverhez fordul, egy olyan v\u00e1laszt kap, amely deleg\u00e1lja a sd1.attacker.com n\u00e9v c\u00edm\u00e9nek meghat\u00e1roz\u00e1s\u00e1t a c\u00e9ljogosultat tartalmaz\u00f3 NS-rekordok megad\u00e1s\u00e1val, a NS-szerverek IP-r\u00e9szletez\u00e9se n\u00e9lk\u00fcl. Mivel a eml\u00edtett NS-szerver kor\u00e1bban nem tal\u00e1lkozott, \u00e9s IP-c\u00edme nem szerepel, a rezolver megpr\u00f3b\u00e1lja meghat\u00e1rozni a NS-szerver IP-c\u00edm\u00e9t, k\u00e9rd\u00e9st k\u00fcldve a c\u00e9ljogosult domain (victim.com) DNS-szerver\u00e9hez.<\/p>\n

\"NXNSAttack<\/a><\/noindex><\/center><\/p>\n

A probl\u00e9ma az, hogy a t\u00e1mad\u00f3 hatalmas list\u00e1t adhat vissza l\u00e9tez\u0151 NS-szerverekr\u0151l, amelyek nem l\u00e9tez\u0151 \u00e1lv\u00e9gz\u0151d\u00e9sekkel hirdetik a s\u00e9rtett aldomainjeit (fake-1.victim.com, fake-2.victim.com,... fake-1000.victim.com). A felold\u00f3 megpr\u00f3b\u00e1lja elk\u00fcldeni a DNS-k\u00e9rd\u00e9st a s\u00e9rtett DNS-szervernek, de v\u00e1laszt kap, hogy a domain nem tal\u00e1lhat\u00f3, majd megpr\u00f3b\u00e1lja meghat\u00e1rozni a k\u00f6vetkez\u0151 NS-szervert a list\u00e1n, \u00e9s \u00edgy folytatja, am\u00edg v\u00e9gig nem j\u00e1rja az \u00f6sszes megadott NS-bejegyz\u00e9st a t\u00e1mad\u00f3 \u00e1ltal. Ennek megfelel\u0151en egyetlen t\u00e1mad\u00f3i k\u00e9rd\u00e9sre a felold\u00f3 rengeteg k\u00e9rd\u00e9st k\u00fcld az NS-gazd\u00e1k meghat\u00e1roz\u00e1s\u00e1ra. Mivel az NS-szerver nevek v\u00e9letlenszer\u0171en keletkeznek \u00e9s nem l\u00e9tez\u0151 aldomainjeikre mutatnak, nem ker\u00fclnek a gyors\u00edt\u00f3t\u00e1rba, \u00e9s minden t\u00e1mad\u00f3i k\u00e9rd\u00e9s \u00f6z\u00f6nk\u00e9rd\u00e9seket eredm\u00e9nyez a s\u00e9rtett domaint kiszolg\u00e1l\u00f3 DNS-szerver fel\u00e9.<\/p>\n

\"NXNSAttack<\/a><\/noindex><\/center><\/p>\n

A kutat\u00f3k megvizsg\u00e1lt\u00e1k a nyilv\u00e1nos DNS-felold\u00f3k v\u00e9dtelens\u00e9g\u00e9nek m\u00e9rt\u00e9k\u00e9t, \u00e9s meg\u00e1llap\u00edtott\u00e1k, hogy a CloudFlare (1.1.1.1) felold\u00f3ra k\u00fcld\u00f6tt k\u00e9r\u00e9sekkel 48-szoros csomagn\u00f6vel\u00e9s (PAF, Packet Amplification Factor) \u00e9rhet\u0151 el, a Google (8.8.8.8) eset\u00e9ben 30-szor, a FreeDNS (37.235.1.174) pedig 50-szer, az OpenDNS (208.67.222.222) pedig 32-szer. Tov\u00e1bbi figyelemre m\u00e9lt\u00f3 mutat\u00f3k a
\nLevel3 (209.244.0.3) - 273-szor, Quad9 (9.9.9.9) - 415-sz\u00f6r
\nSafeDNS (195.46.39.39) - 274-szer, Verisign (64.6.64.6) - 202-szer,
\nUltra (156.154.71.1) - 405-sz\u00f6r, Comodo Secure (8.26.56.26) - 435-sz\u00f6r, DNS.Watch (84.200.69.80) - 486-szor, \u00e9s a Norton ConnectSafe (199.85.126.10) - 569-szer. A BIND 9.12.3 alap\u00fa szerverekn\u00e9l a k\u00e9r\u00e9sek p\u00e1rhuzamos\u00edt\u00e1sa r\u00e9v\u00e9n az er\u0151s\u00edt\u00e9s szintje el\u00e9rheti az 1000-et. A Knot Resolver 5.1.0 er\u0151s\u00edt\u00e9si szintje k\u00f6r\u00fclbel\u00fcl n\u00e9h\u00e1ny tucat (24-48) mivel az NS-nevek meghat\u00e1roz\u00e1sa sorozatosan t\u00f6rt\u00e9nik, \u00e9s egy lek\u00e9rdez\u00e9shez enged\u00e9lyezett l\u00e9p\u00e9sek maxim\u00e1lis sz\u00e1m\u00e1nak bels\u0151 korl\u00e1tj\u00e1ba \u00fctk\u00f6zik.<\/p>\n

K\u00e9t f\u0151 v\u00e9delmi strat\u00e9gi\u00e1t emelnek ki. A DNSSEC rendszerhez aj\u00e1nlott<\/a><\/noindex> haszn\u00e1lni RFC-8198<\/a><\/noindex> a DNS-cache megker\u00fcl\u00e9s\u00e9nek megakad\u00e1lyoz\u00e1s\u00e1ra, mivel az lek\u00e9rdez\u00e9sek v\u00e9letlenszer\u0171 nevekkel t\u00f6rt\u00e9nnek. A m\u00f3dszer l\u00e9nyege, hogy negat\u00edv v\u00e1laszokat gener\u00e1lunk an\u00e9lk\u00fcl, hogy hiteles DNS-szerverekhez forduln\u00e1nk, a DNSSEC seg\u00edts\u00e9g\u00e9vel t\u00f6rt\u00e9n\u0151 tartom\u00e1ny-ellen\u0151rz\u00e9ssel. Egy egyszer\u0171bb m\u00f3dszer a neveket korl\u00e1tozni az egy deleg\u00e1lt lek\u00e9rdez\u00e9s feldolgoz\u00e1sa sor\u00e1n, de ez a m\u00f3dszer probl\u00e9m\u00e1kat okozhat egyes megl\u00e9v\u0151 konfigur\u00e1ci\u00f3kkal, mivel a hat\u00e1rok nincsenek meghat\u00e1rozva a protokollban.<\/p>\n

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

Forr\u00e1s: 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 \u0422\u0435\u043b\u044c-\u0410\u0432\u0438\u0432\u0441\u043a\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0438 \u041c\u0435\u0436\u0434\u0438\u0441\u0446\u0438\u043f\u043b\u0438\u043d\u0430\u0440\u043d\u043e\u0433\u043e \u0446\u0435\u043d\u0442\u0440\u0430 \u0432 \u0413\u0435\u0440\u0446\u043b\u0438\u0438 (\u0418\u0437\u0440\u0430\u0438\u043b\u044c) \u0440\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0430\u043b\u0430 \u043d\u043e\u0432\u044b\u0439 \u043c\u0435\u0442\u043e\u0434 \u0430\u0442\u0430\u043a\u0438 NXNSAttack (PDF), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0439 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c \u043b\u044e\u0431\u044b\u0435 DNS-\u0440\u0435\u0437\u043e\u043b\u0432\u0435\u0440\u044b \u0432 \u043a\u0430\u0447\u0435\u0441\u0442\u0432\u0435 \u0443\u0441\u0438\u043b\u0438\u0442\u0435\u043b\u0435\u0439 \u0442\u0440\u0430\u0444\u0438\u043a\u0430, \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0438\u0432\u0430\u044e\u0449\u0438\u0445 \u0441\u0442\u0435\u043f\u0435\u043d\u044c \u0443\u0441\u0438\u043b\u0435\u043d\u0438\u044f \u0434\u043e 1621 \u0440\u0430\u0437 \u043f\u043e \u0447\u0438\u0441\u043b\u0443 \u043f\u0430\u043a\u0435\u0442\u043e\u0432 (\u043d\u0430 \u043a\u0430\u0436\u0434\u044b\u0439 \u043e\u0442\u043f\u0440\u0430\u0432\u043b\u0435\u043d\u043d\u044b\u0439 \u043a \u0440\u0435\u0437\u043e\u043b\u0432\u0435\u0440\u0443 \u0437\u0430\u043f\u0440\u043e\u0441, \u043c\u043e\u0436\u043d\u043e \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0438 \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440 \u0436\u0435\u0440\u0442\u0432\u044b 1621 \u0437\u0430\u043f\u0440\u043e\u0441) \u0438 \u0434\u043e 163 \u0440\u0430\u0437 \u043f\u043e \u0442\u0440\u0430\u0444\u0438\u043a\u0443. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":82461,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-82460","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\udd47NXNSAttack-t\u00e1mad\u00e1s, amely minden DNS-reszolvert \u00e9rint | ProHoster","description":"A Tel-Aviv Egyetem \u00e9s a Herzl\u00edvai Interdiszciplin\u00e1ris K\u00f6zpont kutat\u00f3csoportja (Izrael)","canonical_url":"https:\/\/prohoster.info\/hu\/blog\/news\/ataka-nxnsattack-zatragivayushhaya-vse-dns-rezolvery","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"hu_HU","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\u0410\u0442\u0430\u043a\u0430 NXNSAttack, \u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u044e\u0449\u0430\u044f \u0432\u0441\u0435 DNS-\u0440\u0435\u0437\u043e\u043b\u0432\u0435\u0440\u044b | 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 \u0422\u0435\u043b\u044c-\u0410\u0432\u0438\u0432\u0441\u043a\u043e\u0433\u043e \u0443\u043d\u0438\u0432\u0435\u0440\u0441\u0438\u0442\u0435\u0442\u0430 \u0438 \u041c\u0435\u0436\u0434\u0438\u0441\u0446\u0438\u043f\u043b\u0438\u043d\u0430\u0440\u043d\u043e\u0433\u043e \u0446\u0435\u043d\u0442\u0440\u0430 \u0432 \u0413\u0435\u0440\u0446\u043b\u0438\u0438 (\u0418\u0437\u0440\u0430\u0438\u043b\u044c)","og:url":"https:\/\/prohoster.info\/hu\/blog\/news\/ataka-nxnsattack-zatragivayushhaya-vse-dns-rezolvery","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":"2020-05-21T17:42:00+00:00","article:modified_time":"2020-05-21T17:42:00+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"82460","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":null,"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":null,"breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2021-02-28 15:37:29","updated":"2022-09-29 14:28:05","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/posts\/82460","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/comments?post=82460"}],"version-history":[{"count":0,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/posts\/82460\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/media\/82461"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/media?parent=82460"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/categories?post=82460"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/hu\/wp-json\/wp\/v2\/tags?post=82460"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}