The release of OpenSSH 8.8 has been published, the open implementation of the client and server for working with SSH 2.0 and SFTP protocols. This release is notable for disabling by default the use of digital signatures based on RSA keys with SHA-1 hash («ssh-rsa»). <\/p>\n
The discontinuation of support for «ssh-rsa» is due to the increased effectiveness of collision attacks with a predefined prefix (the cost of finding a collision is estimated at around $50,000). To check for the use of ssh-rsa in your systems, you can try connecting via ssh with the option «-oHostKeyAlgorithms=-ssh-rsa». Support for RSA signatures with SHA-256 and SHA-512 hashes (rsa-sha2-256\/512), which have been supported since OpenSSH 7.2, remains unchanged. <\/p>\n
In most cases, the discontinuation of support for «ssh-rsa» will not require manual actions from users, as in OpenSSH the UpdateHostKeys setting was previously enabled by default, automatically transitioning clients to more secure algorithms. Migration uses the «hostkeys@openssh.com» protocol extension, allowing server<\/a> after authentication to inform the client about all available host keys. In the case of connecting to hosts with very old versions of OpenSSH on the client side, it is possible to selectively restore the ability to use «ssh-rsa» signatures by adding to ~\/.ssh\/config: Host old_host_name HostkeyAlgorithms +ssh-rsa \tPubkeyAcceptedAlgorithms +ssh-rsa <\/p>\n The new version also addresses a security issue caused by incorrect initialization of the user group in sshd when executing commands specified in the AuthorizedKeysCommand and AuthorizedPrincipalsCommand directives, starting from the release of OpenSSH 6.2. These directives are intended to execute commands under a different user, but in practice, they inherited the group list used when launching sshd. Potentially, this behavior, given certain system settings, allowed the launched handler to gain additional privileges in the system. <\/p>\n The note accompanying the new release also includes a warning about the intention to default the scp utility to use SFTP instead of the outdated SCP\/RCP protocol. SFTP employs more predictable methods for handling names and does not use shell glob pattern processing in file names on the other host, which creates security issues. In particular, with SCP and RCP server<\/a> decides which files and directories to send to the client, while the client only verifies the correctness of the returned object names, which, in the absence of proper checks on the client side, allows the server to pass other names of files different from those requested. The SFTP protocol is free from these issues but does not support revealing special paths such as «~». To address this difference, the previous release of OpenSSH proposed a new SFTP protocol extension for revealing paths ~ and ~user. \u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d \u0440\u0435\u043b\u0438\u0437 OpenSSH 8.8, \u043e\u0442\u043a\u0440\u044b\u0442\u043e\u0439 \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043a\u043b\u0438\u0435\u043d\u0442\u0430 \u0438 \u0441\u0435\u0440\u0432\u0435\u0440\u0430 \u0434\u043b\u044f \u0440\u0430\u0431\u043e\u0442\u044b \u043f\u043e \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430\u043c SSH 2.0 \u0438 SFTP. \u0412\u044b\u043f\u0443\u0441\u043a \u043f\u0440\u0438\u043c\u0435\u0447\u0430\u0442\u0435\u043b\u0435\u043d \u043e\u0442\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u0435\u043c \u043f\u043e \u0443\u043c\u043e\u043b\u0447\u0430\u043d\u0438\u044e \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u044f \u0446\u0438\u0444\u0440\u043e\u0432\u044b\u0445 \u043f\u043e\u0434\u043f\u0438\u0441\u0435\u0439 \u043d\u0430 \u0431\u0430\u0437\u0435 RSA-\u043a\u043b\u044e\u0447\u0435\u0439 \u0441 \u0445\u044d\u0448\u0435\u043c SHA-1 («ssh-rsa»). \u041f\u0440\u0435\u043a\u0440\u0430\u0449\u0435\u043d\u0438\u0435 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 \u043f\u043e\u0434\u043f\u0438\u0441\u0435\u0439 «ssh-rsa» \u043e\u0431\u0443\u0441\u043b\u043e\u0432\u043b\u0435\u043d\u043e \u043f\u043e\u0432\u044b\u0448\u0435\u043d\u0438\u0435\u043c \u044d\u0444\u0444\u0435\u043a\u0442\u0438\u0432\u043d\u043e\u0441\u0442\u0438 \u043a\u043e\u043b\u043b\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0445 \u0430\u0442\u0430\u043a \u0441 \u0437\u0430\u0434\u0430\u043d\u043d\u044b\u043c \u043f\u0440\u0435\u0444\u0438\u043a\u0441\u043e\u043c (\u0441\u0442\u043e\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u0434\u0431\u043e\u0440\u0430 \u043a\u043e\u043b\u043b\u0438\u0437\u0438\u0438 \u043e\u0446\u0435\u043d\u0438\u0432\u0430\u0435\u0442\u0441\u044f \u043f\u0440\u0438\u043c\u0435\u0440\u043d\u043e \u0432 50 \u0442\u044b\u0441\u044f\u0447 \u0434\u043e\u043b\u043b\u0430\u0440\u043e\u0432). \u0414\u043b\u044f […]<\/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-101430","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\udd47The OpenSSH 8.8 release with the deactivation of support for digital signatures rsa-sha | ProHoster","description":"The release of OpenSSH 8.8 has been published, the open implementation of the client 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Source: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"