V Toxcore, referen\u010dn\u00ed implementaci P2P protokolu pro v\u00fdm\u011bnu zpr\u00e1v Tox, byla zji\u0161t\u011bna zranitelnost (CVE-2021-44847), kter\u00e1 potenci\u00e1ln\u011b umo\u017e\u0148uje spustit k\u00f3d p\u0159i zpracov\u00e1n\u00ed speci\u00e1ln\u011b vytvo\u0159en\u00e9ho UDP paketu. Zranitelnosti jsou vystaveny v\u0161ichni u\u017eivatel\u00e9 aplikac\u00ed zalo\u017een\u00fdch na Toxcore, kter\u00e9 nemaj\u00ed vypnut\u00fd transport UDP. K \u00fatoku sta\u010d\u00ed poslat UDP paket, zn\u00e1t IP adresu, s\u00ed\u0165ov\u00fd port a otev\u0159en\u00fd DHT kl\u00ed\u010d ob\u011bti (tyto informace jsou ve\u0159ejn\u011b dostupn\u00e9 v DHT, tj. \u00fatok mohl b\u00fdt proveden na jak\u00e9hokoli u\u017eivatele nebo uzel DHT). <\/p>\n
Probl\u00e9m se projevoval ve verz\u00edch toxcore od 0.1.9 do 0.2.12 a byl odstran\u011bn ve verzi 0.2.13. Z klientsk\u00fdch aplikac\u00ed zat\u00edm vydal aktualizaci s odstran\u011bn\u00edm zranitelnosti pouze projekt qTox. Jako do\u010dasn\u00e9 opat\u0159en\u00ed ochrany lze vypnout pou\u017eit\u00ed UDP a ponechat podporu TCP. <\/p>\n
Zranitelnost je zp\u016fsobena p\u0159ete\u010den\u00edm z\u00e1sobn\u00edku ve funkci handle_request(), kter\u00e9 vznik\u00e1 v d\u016fsledku nespr\u00e1vn\u00e9ho v\u00fdpo\u010dtu velikosti dat v s\u00ed\u0165ov\u00e9m paketu. Zvl\u00e1\u0161\u0165 d\u00e9lka za\u0161ifrovan\u00fdch dat byla ur\u010dena v makru CRYPTO_SIZE, definovan\u00e9m jako \u201e1 + CRYPTO_PUBLIC_KEY_SIZE * 2 + CRYPTO_NONCE_SIZE\u201c, kter\u00e9 bylo n\u00e1sledn\u011b pou\u017eito p\u0159i operaci ode\u010d\u00edt\u00e1n\u00ed \u201elength - CRYPTO_SIZE\u201c. V d\u016fsledku absence z\u00e1vorek v makru do\u0161lo k ode\u010dten\u00ed hodnoty 1 a k se\u010dten\u00ed ostatn\u00edch \u010d\u00e1st\u00ed m\u00edsto ode\u010dten\u00ed sou\u010dtu v\u0161ech hodnot. Nap\u0159\u00edklad m\u00edsto \u201elength - (1 + 32 * 2 + 24)\u201c byla velikost z\u00e1sobn\u00edku vypo\u010d\u00edt\u00e1na jako \u201elength - 1 + 32 * 2 + 24\u201c, co\u017e vedlo k p\u0159eps\u00e1n\u00ed dat na z\u00e1sobn\u00edku, kter\u00e1 se nach\u00e1zela mimo r\u00e1mec z\u00e1sobn\u00edku. \u0412 Toxcore, \u044d\u0442\u0430\u043b\u043e\u043d\u043d\u043e\u0439 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 P2P-\u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 \u043e\u0431\u043c\u0435\u043d\u0430 \u0441\u043e\u043e\u0431\u0449\u0435\u043d\u0438\u044f\u043c\u0438 Tox, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-44847), \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043f\u043e\u0442\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u0438\u043d\u0438\u0446\u0438\u0438\u0440\u043e\u0432\u0430\u0442\u044c \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435 \u043a\u043e\u0434\u0430 \u043f\u0440\u0438 \u043e\u0431\u0440\u0430\u0431\u043e\u0442\u043a\u0435 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u043e\u0433\u043e UDP-\u043f\u0430\u043a\u0435\u0442\u0430. \u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043f\u043e\u0434\u0432\u0435\u0440\u0436\u0435\u043d\u044b \u0432\u0441\u0435 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u0438 \u043f\u0440\u0438\u043b\u043e\u0436\u0435\u043d\u0438\u0439 \u043d\u0430 \u0431\u0430\u0437\u0435 Toxcore, \u0432 \u043a\u043e\u0442\u043e\u0440\u044b\u0445 \u043d\u0435 \u043e\u0442\u043a\u043b\u044e\u0447\u0451\u043d \u0442\u0440\u0430\u043d\u0441\u043f\u043e\u0440\u0442 UDP. \u0414\u043b\u044f \u0430\u0442\u0430\u043a\u0438 \u0434\u043e\u0441\u0442\u0430\u0442\u043e\u0447\u043d\u043e \u043e\u0442\u043f\u0440\u0430\u0432\u0438\u0442\u044c UDP-\u043f\u0430\u043a\u0435\u0442, \u0437\u043d\u0430\u044f IP-\u0430\u0434\u0440\u0435\u0441, \u0441\u0435\u0442\u0435\u0432\u043e\u0439 \u043f\u043e\u0440\u0442 \u0438 \u043e\u0442\u043a\u0440\u044b\u0442\u044b\u0439 DHT-\u043a\u043b\u044e\u0447 \u0436\u0435\u0440\u0442\u0432\u044b (\u0434\u0430\u043d\u043d\u044b\u0435 \u0441\u0432\u0435\u0434\u0435\u043d\u0438\u044f \u0434\u043e\u0441\u0442\u0443\u043f\u043d\u044b \u043f\u0443\u0431\u043b\u0438\u0447\u043d\u043e \u0432 DHT, […]<\/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-102629","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\udd47P\u0159ete\u010den\u00ed bufferu v Toxcore, zneu\u017e\u00edvan\u00e9 prost\u0159ednictv\u00edm odesl\u00e1n\u00ed UDP paketu | ProHoster","description":"V Toxcore, referen\u010dn\u00ed implementaci P2P protokolu pro v\u00fdm\u011bnu zpr\u00e1v Tox, byla zji\u0161t\u011bna zranitelnost (CVE-2021-44847), kter\u00e1 potenci\u00e1ln\u011b umo\u017e\u0148uje spustit k\u00f3d p\u0159i zpracov\u00e1n\u00ed speci\u00e1ln\u011b 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\u043e\u0444\u043e\u0440\u043c\u043b\u0435\u043d\u043d\u043e\u0433\u043e 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Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"