Top 20 OpenSSH Server Best Security Practices

Posted on in Categories CentOS, Debian Linux, fedora linux, FreeBSD, Gentoo Linux, Howto, Linux, Networking, package management, RedHat/Fedora Linux, Security, Suse Linux, Sys admin, Tips, Ubuntu Linux, UNIX last updated January 31, 2016
Don't tell anyone that I'm free

OpenSSH is the implementation of the SSH protocol. OpenSSH is recommended for remote login, making backups, remote file transfer via scp or sftp, and much more. SSH is perfect to keep confidentiality and integrity for data exchanged between two networks and systems. However, the main advantage is server authentication, through the use of public key cryptography. From time to time there are rumors about OpenSSH zero day exploit. Here are a few things you need to tweak in order to improve OpenSSH server security.

Chroot in OpenSSH / SFTP Feature Added To OpenSSH

Posted on in Categories Howto, Linux, Networking, OpenBSD, Security last updated February 20, 2008

For regular user accounts, a properly configured chroot jail is a rock solid security system. I’ve already written about chrooting sftp session using rssh. According to OpenBSD journal OpenSSH devs Damien Miller and Markus Friedl have recently added a chroot security feature to openssh itself:

Unfortunately, setting up a chroot(2) environment is complicated, fragile and annoying to maintain. The most frequent reason our users have given when asking for chroot support in sshd is so they can set up file servers that limit semi-trusted users to be able to access certain files only. Because of this, we have made this particular case very easy to configure.

This commit adds a chroot(2) facility to sshd, controlled by a new sshd_config(5) option “ChrootDirectory”. This can be used to “jail” users into a limited view of the filesystem, such as their home directory, rather than letting them see the full filesystem.