{"id":101115,"date":"2021-08-28T10:22:53","date_gmt":"2021-08-28T08:22:53","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-libssh-privodyashhaya-k-perepolneniyu-bufera"},"modified":"2021-08-28T10:22:53","modified_gmt":"2021-08-28T08:22:53","slug":"uyazvimost-v-libssh-privodyashhaya-k-perepolneniyu-bufera","status":"publish","type":"post","link":"https:\/\/prohoster.info\/it\/blog\/news\/uyazvimost-v-libssh-privodyashhaya-k-perepolneniyu-bufera","title":{"rendered":"Vulnerabilit\u00e0 in libssh che porta a un buffer overflow","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Nella libreria libssh (da non confondere con libssh2), progettata per aggiungere supporto client e server per il protocollo SSHv2 nei programmi in linguaggio C, \u00e8 stata identificata una vulnerabilit\u00e0 (CVE-2021-3634) che porta a un overflow del buffer durante l'inizializzazione del processo di cambio chiave (rekey) utilizzando un meccanismo di scambio chiave che applica un differente algoritmo di hashing. Il problema \u00e8 stato risolto nella versione 0.9.6. <\/p>\n

Il nocciolo della questione \u00e8 che l'operazione di cambio chiave consente l'uso di hash crittografici con dimensioni diverse da quelle dell'algoritmo utilizzato inizialmente. In questo contesto, la memoria per l'hash in libssh veniva allocata in base alla dimensione dell'hash originale e l'uso di un hash di dimensioni maggiori porta alla sovrascrittura dei dati al di fuori del buffer allocato. Come metodo di protezione alternativo, si pu\u00f2 limitare l'elenco dei metodi di scambio chiave a soli algoritmi con dimensioni di hash identiche. Ad esempio, per vincolarsi a SHA256, nel codice si pu\u00f2 aggiungere: rc = ssh_options_set(s->ssh.session, SSH_OPTIONS_KEY_EXCHANGE, 'diffie-hellman-group14-sha256,curve25519-sha256,ecdh-sha2-nistp256');
\n
Fonte: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u0435 libssh (\u043d\u0435 \u043f\u0443\u0442\u0430\u0442\u044c \u0441 libssh2), \u043f\u0440\u0435\u0434\u043d\u0430\u0437\u043d\u0430\u0447\u0435\u043d\u043d\u043e\u0439 \u0434\u043b\u044f \u0434\u043e\u0431\u0430\u0432\u043b\u0435\u043d\u0438\u044f \u043a\u043b\u0438\u0435\u043d\u0442\u0441\u043a\u043e\u0439 \u0438 \u0441\u0435\u0440\u0432\u0435\u0440\u043d\u043e\u0439 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 SSHv2 \u0432 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u044b \u043d\u0430 \u044f\u0437\u044b\u043a\u0435 \u0421\u0438, \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2021-3634), \u043f\u0440\u0438\u0432\u043e\u0434\u044f\u0449\u0430\u044f \u043a \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044e \u0431\u0443\u0444\u0435\u0440\u0430 \u043f\u0440\u0438 \u0438\u043d\u0438\u0446\u0438\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0438 \u043f\u0440\u043e\u0446\u0435\u0441\u0441\u0430 \u0441\u043c\u0435\u043d\u044b \u043a\u043b\u044e\u0447\u0430 (rekey) \u0441 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435\u043c \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c\u0430 \u043e\u0431\u043c\u0435\u043d\u0430 \u043a\u043b\u044e\u0447\u0430\u043c\u0438, \u043f\u0440\u0438\u043c\u0435\u043d\u044f\u044e\u0449\u0435\u0433\u043e \u0434\u0440\u0443\u0433\u043e\u0439 \u0430\u043b\u0433\u043e\u0440\u0438\u0442\u043c \u0445\u044d\u0448\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430 \u0432 \u0432\u044b\u043f\u0443\u0441\u043a\u0435 0.9.6. \u0421\u0443\u0442\u044c \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u044b \u0432 \u0442\u043e\u043c, \u0447\u0442\u043e \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u044f \u0441\u043c\u0435\u043d\u044b […]<\/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-101115","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\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\udd47Vulnerabilit\u00e0 in libssh che porta a un overflow del buffer | ProHoster","description":"Nella libreria libssh (da non confondere con libssh2), destinata ad aggiungere supporto client e server per il protocollo SSHv2 nei programmi in linguaggio C, \u00e8 stata individuata una vulnerabilit\u00e0 (CVE-2021-3634) che porta a un 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