{"id":38635,"date":"2019-10-31T22:24:58","date_gmt":"2019-10-31T19:24:58","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novaya-tehnika-ataki-po-storonnim-kanalam-pozvolyayushhaya-vosstanovit-klyuchi-ecdsa\/"},"modified":"2019-10-31T22:24:58","modified_gmt":"2019-10-31T19:24:58","slug":"novaya-tehnika-ataki-po-storonnim-kanalam-pozvolyayushhaya-vosstanovit-klyuchi-ecdsa","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pt\/blog\/news\/novaya-tehnika-ataki-po-storonnim-kanalam-pozvolyayushhaya-vosstanovit-klyuchi-ecdsa","title":{"rendered":"Uma nova t\u00e9cnica de ataque por canais laterais que permite a recupera\u00e7\u00e3o de chaves ECDSA.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Pesquisadores da Universidade Masaryk revelaram<\/a><\/noindex> informa\u00e7\u00f5es sobre vulnerabilidades<\/a><\/noindex> em v\u00e1rias implementa\u00e7\u00f5es do algoritmo de assinatura digital ECDSA\/EdDSA, que permitem recuperar o valor da chave privada com base na an\u00e1lise de vazamentos de informa\u00e7\u00f5es sobre bits individuais que surgem ao aplicar m\u00e9todos de an\u00e1lise por canais laterais. As vulnerabilidades receberam o nome de Minerva. <\/p>\n

Os projetos mais conhecidos afetados pelo m\u00e9todo de ataque proposto s\u00e3o OpenJDK\/OracleJDK (CVE-2019-2894) e a biblioteca Libgcrypt<\/a><\/noindex> (CVE-2019-13627), utilizada no GnuPG. O problema tamb\u00e9m afeta MatrixSSL<\/a><\/noindex>, Crypto++<\/a><\/noindex>, wolfCrypt<\/a><\/noindex>, elliptic<\/a><\/noindex>, jsrsasign<\/a><\/noindex>, python-ecdsa<\/a><\/noindex>, ruby_ecdsa<\/a><\/noindex>, fastecdsa<\/a><\/noindex>, easy-ecc<\/a><\/noindex> e os cart\u00f5es inteligentes Athena IDProtect. N\u00e3o testados, mas potencialmente vulner\u00e1veis tamb\u00e9m s\u00e3o os cart\u00f5es Valid S\/A IDflex V, SafeNet eToken 4300 e TecSec Armored Card, que utilizam m\u00f3dulos padr\u00e3o de ECDSA. <\/p>\n

O problema j\u00e1 foi resolvido nas vers\u00f5es libgcrypt 1.8.5 e wolfCrypt 4.1.0, enquanto os outros projetos ainda n\u00e3o lan\u00e7aram atualiza\u00e7\u00f5es. \u00c9 poss\u00edvel acompanhar a corre\u00e7\u00e3o da vulnerabilidade no pacote libgcrypt em distribui\u00e7\u00f5es nas seguintes p\u00e1ginas: Debian<\/a><\/noindex>, Ubuntu<\/a><\/noindex>, RHEL<\/a><\/noindex>, Fedora<\/a><\/noindex>, openSUSE\/SUSE<\/a><\/noindex>, FreeBSD<\/a><\/noindex>, Arch<\/a><\/noindex>.<\/p>\n

Vulnerabilidades n\u00e3o est\u00e3o afetados<\/a><\/noindex> OpenSSL, Botan, mbedTLS e BoringSSL. N\u00e3o foram testados ainda Mozilla NSS, LibreSSL, Nettle, BearSSL, cryptlib, OpenSSL em modo FIPS, Microsoft .NET crypto,
\nlibkcapi do n\u00facleo Linux, Sodium e GnuTLS.<\/p>\n

O problema \u00e9 causado pela possibilidade de determinar os valores de bits individuais durante a multiplica\u00e7\u00e3o escalar em opera\u00e7\u00f5es com curvas el\u00edpticas. Para extrair informa\u00e7\u00f5es sobre os bits, m\u00e9todos indiretos s\u00e3o utilizados, como a avalia\u00e7\u00e3o da lat\u00eancia durante os c\u00e1lculos. Para a ataque, \u00e9 necess\u00e1rio ter acesso n\u00e3o privilegiado ao host onde a gera\u00e7\u00e3o da assinatura digital \u00e9 feita (n\u00e3o exclui<\/a><\/noindex> um ataque remoto, mas isso \u00e9 significativamente mais complicado e requer um grande volume de dados para an\u00e1lise, portanto pode ser considerado improv\u00e1vel). Para carregar dispon\u00edvel<\/a><\/noindex> o kit de ferramentas utilizado para o ataque.<\/p>\n

Apesar do pequeno tamanho da vazamento, para a ECDSA, definir at\u00e9 mesmo alguns bits de informa\u00e7\u00e3o sobre o vetor de inicializa\u00e7\u00e3o (nonce) \u00e9 suficiente para realizar um ataque de recupera\u00e7\u00e3o sequencial de toda a chave privada. Segundo os autores do m\u00e9todo, a an\u00e1lise de algumas centenas a milhares de assinaturas digitais geradas para mensagens conhecidas pelo atacante \u00e9 suficiente para a recupera\u00e7\u00e3o bem-sucedida da chave. Por exemplo, para determinar a chave privada usada no cart\u00e3o inteligente Athena IDProtect baseado no chip Inside Secure AT90SC, analisaram-se 11 mil assinaturas digitais ao usar a curva el\u00edptica secp256r1. O tempo total do ataque foi de 30 minutos.<\/p>\n

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

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

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\u043f\u0440\u043e\u0435\u043a\u0442\u0430\u043c\u0438, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0435\u043d\u043d\u044b\u0439 \u043c\u0435\u0442\u043e\u0434 \u0430\u0442\u0430\u043a\u0438, \u044f\u0432\u043b\u044f\u044e\u0442\u0441\u044f OpenJDK\/OracleJDK (CVE-2019-2894) \u0438 […]<\/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-38635","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\udd47Nova t\u00e9cnica de ataque por 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