{"id":114452,"date":"2024-03-20T12:25:49","date_gmt":"2024-03-20T10:25:49","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/ataka-na-nekotorye-protokoly-na-osnove-udp-privodyashhaya-k-zacziklivaniyu-obmena-paketami"},"modified":"2024-03-20T12:25:49","modified_gmt":"2024-03-20T10:25:49","slug":"ataka-na-nekotorye-protokoly-na-osnove-udp-privodyashhaya-k-zacziklivaniyu-obmena-paketami","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/ataka-na-nekotorye-protokoly-na-osnove-udp-privodyashhaya-k-zacziklivaniyu-obmena-paketami","title":{"rendered":"\u00datok na n\u011bkter\u00e9 protokoly zalo\u017een\u00e9 na UDP, vedouc\u00ed k zacyklen\u00ed v\u00fdm\u011bny paket\u016f.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Koordina\u010dn\u00ed centrum CERT (skupina pro reakci na po\u010d\u00edta\u010dov\u00e9 mimo\u0159\u00e1dn\u00e9 situace) zve\u0159ejnilo varov\u00e1n\u00ed o s\u00e9rii zranitelnost\u00ed v implementac\u00edch r\u016fzn\u00fdch aplika\u010dn\u00edch protokol\u016f, kter\u00e9 vyu\u017e\u00edvaj\u00ed protokol UDP jako p\u0159enosov\u00fd protokol. Zranitelnosti mohou b\u00fdt vyu\u017eity k organizaci \u00fatok\u016f na dostupnost d\u00edky mo\u017enosti cyklick\u00e9 v\u00fdm\u011bny paket\u016f mezi dv\u011bma hostiteli. Nap\u0159\u00edklad \u00fato\u010dn\u00edci mohou dos\u00e1hnout vy\u010derp\u00e1n\u00ed dostupn\u00e9 \u0161\u00ed\u0159ky p\u00e1sma s\u00edt\u011b, zablokov\u00e1n\u00ed funkce s\u00ed\u0165ov\u00fdch slu\u017eeb (nap\u0159\u00edklad prost\u0159ednictv\u00edm vysok\u00e9ho zat\u00ed\u017een\u00ed a p\u0159ekro\u010den\u00ed limitu intenzity po\u017eadavk\u016f) a realizace zesilova\u010d\u016f provozu pro DDoS \u00fatoky. <\/p>\n

Mezi protokoly, jejich\u017e n\u011bkter\u00e9 implementace jsou zraniteln\u00e9, pat\u0159\u00ed DNS, NTP, TFTP, Echo (RFC862), Chargen (RFC864) a QOTD (RFC865). P\u0159\u00edtomnost zranitelnosti (CVE-2024-2169) byla potvrzena v n\u011bkter\u00fdch produktech spole\u010dnost\u00ed Cisco, Microsoft, Broadcom, Brother, Honeywell (CVE-2024-1309) a MikroTik. Jako obran\u00e1 opat\u0159en\u00ed k zablokov\u00e1n\u00ed zranitelnost\u00ed se doporu\u010duje na firewallech povolit blokaci spoofingu (uRPF), omezit p\u0159\u00edstup k nepot\u0159ebn\u00fdm UDP slu\u017eb\u00e1m a nastavit omezen\u00ed intenzity provozu (rate-limit a QoS). <\/p>\n

Zranitelnosti jsou zp\u016fsobeny t\u00edm, \u017ee protokol UDP nen\u00ed chr\u00e1n\u011bn proti spoofingu adres. Pokud na p\u0159echodov\u00fdch sm\u011brova\u010d\u00edch chyb\u00ed ochrana proti spoofingu, \u00fato\u010dn\u00edk m\u016f\u017ee uv\u00e9st IP adresu libovoln\u00e9ho serveru v UDP paketu a poslat tento paket na jin\u00fd server, kter\u00fd vr\u00e1t\u00ed odpov\u011b\u010f na uvedenou fale\u0161nou adresu. Metoda \u00fatoku spo\u010d\u00edv\u00e1 ve vytvo\u0159en\u00ed situace, kdy si servery se zraniteln\u00fdmi implementacemi protokolu vz\u00e1jemn\u011b pos\u00edlaj\u00ed pakety. Nap\u0159\u00edklad v reakci na p\u0159ijat\u00fd paket m\u016f\u017ee c\u00edlov\u00fd server odeslat odpov\u011b\u010f s k\u00f3dem chyby, a server, jeho\u017e adresu \u00fato\u010dn\u00edk podstr\u010dil, vr\u00e1t\u00ed svou odpov\u011b\u010f, co\u017e op\u011bt povede k n\u00e1vratu paketu s k\u00f3dem chyby. Takto servery<\/a> se pakety za\u010dnou nekone\u010dn\u011b hr\u00e1t mezi sebou v \u201eping-pongu.

\"\u00datok<\/center> <\/p>\n

Je pozoruhodn\u00e9, \u017ee podobn\u00e1 metoda \u00fatoku nen\u00ed nov\u00e1 a v serveru<\/a> Synchronizace \u010dasu ntpd byla chr\u00e1n\u011bna p\u0159ed jednou variantou \u00fatoku, kter\u00e1 byla odstran\u011bna u\u017e v roce 2009 (CVE-2009-3563) ve verz\u00edch 4.2.4p8 a 4.2.5. \u00datok spo\u010d\u00edval v posl\u00e1n\u00ed NTP paketu s podvr\u017eenou adresou a nastaven\u00fdm flagem MODE_PRIVATE, p\u0159i\u010dem\u017e c\u00edlov\u00fd server p\u0159i zpracov\u00e1n\u00ed tohoto paketu vracel odpov\u011b\u010f o nemo\u017enosti pou\u017eit\u00ed soukrom\u00e9ho re\u017eimu, p\u0159i\u010dem\u017e flag MODE_PRIVATE z\u016fst\u00e1val ve vyj\u00e1d\u0159en\u00ed. Jin\u00fd server pak tak\u00e9 nemohl tento flag zpracovat a vracel svou odpov\u011b\u010f, co\u017e vedlo k cyklen\u00ed v\u00fdm\u011bny paket\u016f mezi dv\u011bma NTP servery. Co se DNS protokolu t\u00fd\u010de, varov\u00e1n\u00ed o mo\u017enosti proveden\u00ed podobn\u00e9ho \u00fatoku bylo zve\u0159ejn\u011bno u\u017e v roce 1996. <\/p>\n

Glob\u00e1ln\u00ed skenov\u00e1n\u00ed adres v internetu uk\u00e1zalo, \u017ee v sou\u010dasnosti je v s\u00edti p\u0159\u00edtomno minim\u00e1ln\u011b 23 tis\u00edc zraniteln\u00fdch TFTP server\u016f, 63 tis\u00edc DNS server\u016f, 89 tis\u00edc NTP server\u016f, 56 tis\u00edc Echo\/RFC862 slu\u017eeb, 22 tis\u00edc Chargen\/RFC864 slu\u017eeb a 21 tis\u00edc QOTD\/RFC865 slu\u017eeb. P\u0159edpokl\u00e1d\u00e1 se, \u017ee v p\u0159\u00edpad\u011b NTP server\u016f je p\u0159\u00edtomnost neopraven\u00e9 zranitelnosti spojena s pou\u017e\u00edv\u00e1n\u00edm velmi star\u00fdch verz\u00ed ntpd, vydan\u00fdch p\u0159ed rokem 2010. Slu\u017eby Echo, Chargen a QOTD jsou zraniteln\u00e9 ji\u017e od sv\u00e9ho vzniku d\u00edky sv\u00e9 architektu\u0159e. Situace se servery TFTP a DNS vy\u017eaduje jedn\u00e1n\u00ed s jejich administr\u00e1tory. Servery atftpd a tftpd t\u00e9to problematice nejsou vystaveny, proto\u017ee p\u0159i odesl\u00e1n\u00ed odpov\u011bdi pou\u017e\u00edvaj\u00ed n\u00e1hodn\u00e9 \u010d\u00edslo v\u00fdchoz\u00edho s\u00ed\u0165ov\u00e9ho portu. Mezi zraniteln\u00fdmi DNS servery je zm\u00edn\u011bn dproxy-nexgen. V produktech Microsoft probl\u00e9m vystupuje v WDS (Windows Deployment Services), a v produktech Cisco se probl\u00e9m vyskytuje v routerech \u0159ad 2800 a 2970.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u041a\u043e\u043e\u0440\u0434\u0438\u043d\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0439 \u0446\u0435\u043d\u0442\u0440 CERT (\u043a\u043e\u043c\u043f\u044c\u044e\u0442\u0435\u0440\u043d\u0430\u044f \u0433\u0440\u0443\u043f\u043f\u0430 \u0440\u0435\u0430\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043d\u0430 \u0447\u0440\u0435\u0437\u0432\u044b\u0447\u0430\u0439\u043d\u044b\u0435 \u0441\u0438\u0442\u0443\u0430\u0446\u0438\u0438), \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043b \u043f\u0440\u0435\u0434\u0443\u043f\u0440\u0435\u0436\u0434\u0435\u043d\u0438\u0435 \u043e \u0441\u0435\u0440\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 \u0432 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u044f\u0445 \u0440\u0430\u0437\u043b\u0438\u0447\u043d\u044b\u0445 \u043f\u0440\u0438\u043a\u043b\u0430\u0434\u043d\u044b\u0445 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u043e\u0432, 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[…]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":114453,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-114452","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\udd47\u00datok na n\u011bkter\u00e9 UDP protokoly, kter\u00fd vede k cyklen\u00ed v\u00fdm\u011bny paket\u016f | ProHoster","description":"Koordina\u010dn\u00ed centrum CERT (po\u010d\u00edta\u010dov\u00e1 skupina reaguj\u00edc\u00ed na mimo\u0159\u00e1dn\u00e9 ud\u00e1losti) zve\u0159ejnilo varov\u00e1n\u00ed o s\u00e9rii zranitelnost\u00ed v implementac\u00edch r\u016fzn\u00fdch aplika\u010dn\u00edch 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\u0437\u0430\u0446\u0438\u043a\u043b\u0438\u0432\u0430\u043d\u0438\u044e \u043e\u0431\u043c\u0435\u043d\u0430 \u043f\u0430\u043a\u0435\u0442\u0430\u043c\u0438 | ProHoster","og:description":"\u041a\u043e\u043e\u0440\u0434\u0438\u043d\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0439 \u0446\u0435\u043d\u0442\u0440 CERT (\u043a\u043e\u043c\u043f\u044c\u044e\u0442\u0435\u0440\u043d\u0430\u044f \u0433\u0440\u0443\u043f\u043f\u0430 \u0440\u0435\u0430\u0433\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u043d\u0430 \u0447\u0440\u0435\u0437\u0432\u044b\u0447\u0430\u0439\u043d\u044b\u0435 \u0441\u0438\u0442\u0443\u0430\u0446\u0438\u0438), \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043b \u043f\u0440\u0435\u0434\u0443\u043f\u0440\u0435\u0436\u0434\u0435\u043d\u0438\u0435 \u043e \u0441\u0435\u0440\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0435\u0439 \u0432 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u044f\u0445 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