{"id":73151,"date":"2020-03-07T14:42:03","date_gmt":"2020-03-07T11:42:03","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-pppd-i-lwip-pozvolyayushhaya-udalyonno-vypolnit-kod-s-pravami-root"},"modified":"2020-03-07T14:42:03","modified_gmt":"2020-03-07T11:42:03","slug":"uyazvimost-v-pppd-i-lwip-pozvolyayushhaya-udalyonno-vypolnit-kod-s-pravami-root","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/uyazvimost-v-pppd-i-lwip-pozvolyayushhaya-udalyonno-vypolnit-kod-s-pravami-root","title":{"rendered":"Zranite\u013enos\u0165 v pppd a lwIP, ktor\u00e1 umo\u017e\u0148uje vzdialen\u00e9 vykonanie k\u00f3du s pr\u00e1vami root","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

V bal\u00edku pppd bola zisten\u00e1<\/a><\/noindex> zranite\u013enos\u0165<\/a><\/noindex> (CVE-2020-8597<\/a><\/noindex>), ktor\u00e1 umo\u017e\u0148uje vykona\u0165 svoj k\u00f3d prostredn\u00edctvom odoslania \u0161peci\u00e1lne upraven\u00fdch po\u017eiadaviek na autentifik\u00e1ciu k syst\u00e9mom pou\u017e\u00edvaj\u00facim protokol PPP (Point-to-Point Protocol) alebo PPPoE (PPP cez Ethernet). Tieto protokoly sa zvy\u010dajne pou\u017e\u00edvaj\u00fa poskytovate\u013emi na organiz\u00e1ciu pripojenia cez Ethernet alebo DSL a taktie\u017e sa vyu\u017e\u00edvaj\u00fa v niektor\u00fdch VPN (napr\u00edklad pptpd a openfortivpn<\/a><\/noindex>). Na overenie zranite\u013enosti svojich syst\u00e9mov bol pripraven\u00fd<\/a><\/noindex> prototyp exploit.<\/p>\n

Zranite\u013enos\u0165 je sp\u00f4soben\u00e1 prete\u010den\u00edm vyrovn\u00e1vacej pam\u00e4te v implement\u00e1cii autentifika\u010dn\u00e9ho protokolu EAP (Extensible Authentication Protocol). \u00datok m\u00f4\u017ee by\u0165 vykonan\u00fd v \u0161t\u00e1diu pred autentifik\u00e1ciou prostredn\u00edctvom odoslania bal\u00edka s typom EAPT_MD5CHAP, ktor\u00fd obsahuje ve\u013emi dlh\u00e9 meno hostite\u013ea, nedokonal\u00e9 v pridelenom vyrovn\u00e1vacej pam\u00e4ti. V d\u00f4sledku chyby v k\u00f3de kontroly ve\u013ekosti po\u013ea rhostname m\u00f4\u017ee \u00fato\u010dn\u00edk prep\u00edsa\u0165 \u00fadaje mimo vyrovn\u00e1vacej pam\u00e4te na z\u00e1sobn\u00edku a dosiahnu\u0165 vzdialen\u00e9 vykonanie svojho k\u00f3du s pr\u00e1vami root. Zranite\u013enos\u0165 sa prejavuje na strane servera aj klienta, teda m\u00f4\u017ee by\u0165 napadnut\u00fd nielen server, ale aj klient, sna\u017eiaci sa pripoji\u0165 k serveru ovl\u00e1dan\u00e9mu \u00fato\u010dn\u00edkom (napr\u00edklad \u00fato\u010dn\u00edk m\u00f4\u017ee najprv hackn\u00fa\u0165 server cez zranite\u013enos\u0165 a potom za\u010da\u0165 nap\u00e1da\u0165 pripojen\u00fdch klientov).<\/p>\n

Probl\u00e9m sa t\u00fdka verzi\u00ed pppd<\/a><\/noindex> od 2.4.2 do 2.4.8 vr\u00e1tane a bol odstr\u00e1nen\u00fd vo forme patchu<\/a><\/noindex>. Zranite\u013enos\u0165 taktie\u017e t\u00fdka<\/a><\/noindex> z\u00e1sobn\u00edka lwIP<\/a><\/noindex>, ale v predvolenej konfigur\u00e1cii v lwIP podpora EAP nie je zapnut\u00e1.<\/p>\n

Stav odstr\u00e1nenia probl\u00e9mu v distrib\u00faci\u00e1ch si m\u00f4\u017eete pozrie\u0165 na t\u00fdchto str\u00e1nkach: Debian<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, RHEL<\/a><\/noindex>, Fedora<\/a><\/noindex>, SUSE<\/a><\/noindex>, OpenWRT<\/a><\/noindex>, Arch<\/a><\/noindex>, NetBSD<\/a><\/noindex>. V RHEL, OpenWRT a SUSE je bal\u00edk pppd zostaven\u00fd s aktivovanou ochranou \u00abStack Smashing Protection\u00bb (re\u017eim \u00ab-fstack-protector\u00bb v gcc), \u010do obmedzuje mo\u017enos\u0165 zneu\u017eitia p\u00e1du. Okrem distrib\u00faci\u00ed bola zranite\u013enos\u0165 potvrden\u00e1 aj v niektor\u00fdch produktoch. Cisco<\/a><\/noindex> (CallManager), TP-LINK<\/a><\/noindex> a Synology (DiskStation Manager, VisualStation VS960HD a Router Manager), ktor\u00e9 pou\u017e\u00edvaj\u00fa k\u00f3d pppd alebo lwIP.<\/p>\n

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

Zdroj: opennet.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u043f\u0430\u043a\u0435\u0442\u0435 pppd \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2020-8597), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0438\u0442\u044c \u0441\u0432\u043e\u0439 \u043a\u043e\u0434 \u0447\u0435\u0440\u0435\u0437 \u043e\u0442\u043f\u0440\u0430\u0432\u043a\u0443 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u044b\u0445 \u0437\u0430\u043f\u0440\u043e\u0441\u043e\u0432 \u043d\u0430 \u0430\u0443\u0442\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0446\u0438\u044e \u043a \u0441\u0438\u0441\u0442\u0435\u043c\u0430\u043c, \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044e\u0449\u0438\u043c \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b PPP (Point-to-Point Protocol) \u0438\u043b\u0438 PPPoE (PPP over Ethernet). \u0414\u0430\u043d\u043d\u044b\u0435 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u044b \u043e\u0431\u044b\u0447\u043d\u043e \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u044e\u0442\u0441\u044f \u043f\u0440\u043e\u0432\u0430\u0439\u0434\u0435\u0440\u0430\u043c\u0438 \u0434\u043b\u044f \u043e\u0440\u0433\u0430\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u043e\u0434\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u0447\u0435\u0440\u0435\u0437 Ethernet \u0438\u043b\u0438 DSL, \u0430 \u0442\u0430\u043a\u0436\u0435 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u044e\u0442\u0441\u044f \u0432 \u043d\u0435\u043a\u043e\u0442\u043e\u0440\u044b\u0445 VPN (\u043d\u0430\u043f\u0440\u0438\u043c\u0435\u0440, pptpd \u0438 openfortivpn). \u0414\u043b\u044f \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0438 \u043f\u043e\u0434\u0432\u0435\u0440\u0436\u0435\u043d\u043d\u043e\u0441\u0442\u0438 \u0441\u0432\u043e\u0438\u0445 […]<\/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-73151","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\udd47Zranite\u013enos\u0165 v pppd a lwIP, ktor\u00e1 umo\u017e\u0148uje vzdialen\u00e9 vykonanie k\u00f3du s pr\u00e1vami root | ProHoster","description":"V bal\u00edku pppd bola zisten\u00e1 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