Configuring SFTP server with chroot on CentOS 5.5 | Thanixrajan's Blog. How to Configure SFTP with Chroot-Jail on CentOS — BIN63. How to Set Up a Secure Chrooted Jail with RSSH | AC Hawkins. In this guide I will show you how to install and configure Restricted SSH (rssh) using the default port 22, create a chrooted jail for your users and how to properly secure it all afterwards. This method is tried and tested as I originally wrote this for my own benefit when building servers at work. There are 5 steps: Installing rsshConfiguring rsshBuilding the chrooted jailLocking it all downAdding users with rssh over SCP and/or SFTP access to the jail. Confirmed compatable with default installations of CentOS 5.2 and Redhat 5.2 During this guide the CentOS/Redhat default webroot of /var/www/html will be used. Let’s get started! In a terminal type:cd /tmp wget rpm -ivh rssh-2.3.2-1.2.el5.rf.i386.rpm Type (with root privilages):gedit /etc/rssh.conf Change the umask from 022 to 002.
Umask = 002 Uncomment chrootpath and change to to /var/www allowsftp #allowcvs #allowrdist mkdir -p /var/www/usr/bin mkdir -p /var/www/libexec/openssh. Bind 9 in a Chroot Jail (CentOS) How to Build a Chroot Environment in CentOS. The purpose of a chroot jail is to allow you to run a virtual file system within a larger one. You can use it for any number of reasons, including virtual shared hosting accounts. The user whose login account is associated with a chroot jail can use an entire virtual Linux distribution within the jail, but that user cannot navigate beyond the jail into the larger system. Using YUM, the Red Hat and CentOS package manager, it is relatively easy to create a chroot jail. Just follow these steps. 1. ShareThis Related Posts. Easy Centos SFTP Chroot User Jail | Dastrup Tech Logs. June 14, 2010 I had to set up a SFTP site for a customer which required a true chroot user jail - each user would go directly to their own home directory.
Other requirements included: Users could not see other users folders, Authentication via Active Directory, and no SSH or other access. After much research and trial-and-error, I figured out that OpenSSH simply would not work. The reason is OpenSSH, while it offers a ChrootDirectory option, has a very annoying limitation. From the man pages: “This path, and all its components, must be root-owned directories that are not writable by any other user or group.” So tell me, how do you chroot a user to their home directory if their home directory must be owned by root and not writable to the users? You can’t. Template homedir = /home/%U/%U which would create a home directory like this: /home/joeblow/joeblow and in /etc/ssh/sshd_config set this: ChrootDirectory /home/%u Change the OpenSSH port: ProFTPD 1.3.3rc4 build configuration options: .
SFTP Only Chroot Jail (OpenSSH v5) - Adam's World. Intro This tutorial is a follow-up to the version 6 update of OpenSSH. Since version 5, jailing has been natively supported. NOTE: This tutorial is for attempting to jail users to their home directory and allowing them ONLY sftp access. NOTE: This works and has been tested on centos 6.3 What it does This will majorly increase security for a multi-user server. The main things it does are: Lock users to their home directory --This blocks their eyes from the rest of your system and from files like: system binaries, other users' files, backups, configuration files Disable regular ssh access --Many users just having a web site won't need an actual command interface.
FTP already does this!!! Package names updated as of 12/16/2012 (December 16) The Tutorial This tutorial uses the /opt directory to install the necessary dependences. NOTE: The jailing setup for OpenSSH ver6 is much cleaner and uses less hacks then version 4. Another NOTE: This setup is meant for installing on a fresh server. . Congrats! How to: Configure User Account to Use a Restricted Shell ( rssh ) Now rssh is installed. Next logical step is configure user to use rssh. All you have to do is set a user account shell to /usr/bin/rssh. The following examples adds user didi to system with /usr/bin/rssh. Create a new user with /usr/bin/rssh Login as the root user Type the following command to create a new user called didi: # useradd -m -d /home/didi -s /usr/bin/rssh didi # passwd didi Change existing user shell to /usr/bin/rssh Use chsh command or usermod command to change user login shell: # usermod -s /usr/bin/rssh old-user-name # usermod -s /usr/bin/rssh vivek # chsh -s /usr/bin/rssh vivek Try login via ssh or sftp Now try login via ssh or sftp using username didi: $ sftp didi@my.backup.server.com OR $ ssh didi@my.backup.server.com Output: didi@my.backup.server.com's password: TYPE-THE-PASSWORD Linux my.backup.server.com 2.6.22-14-generic #1 SMP Tue Dec 18 08:02:57 UTC 2007 i686 Last login: Thu Dec 27 16:35:04 2007 from localhost This account is restricted by rssh.
Linux Configure rssh Chroot Jail To Lock Users To Their Home Directories Only. Rssh support chrooting option. If you want to chroot users, use chrootpath option. It is used to set the directory where the root of the chroot jail will be located. This is a security feature. A chroot on Linux or Unix OS is an operation that changes the root directory. It affects only the current process and its children. If your default home directory is /home/vivek normal user can access files in /etc, /sbin or /bin directory. This allows an attacker to install programs / backdoor via your web server in /tmp. chroot allows to restrict file system access and locks down user to their own directory. Configuring rssh chroot => Chroot directory: /users. => Required directories in jail: /users/dev - Device file/users/etc - Configuration file such as passwd/users/lib - Shared libs/users/usr - rssh and other binaries/users/bin - Copy default shell such as /bin/csh or /bin/bash => Required files in jail at /users directory (default for RHEL / CentOS / Debian Linux): A note about jail file system.
Centos 5 « DotNux – Unix/Linux Technical Mini Howto. Install OpenSSH 5.2 on CentOS 5 « DotNux – Unix/Linux Technical Mini Howto. Chrooted SFTP with OpenSSH 5 | robbyt.com. Building a Secure User Environment with SSH ChRoot. Building a Secure User Environment with SSH ChRootGroups What It Is Chroot, as you may know, alters the effective root directory of a user or process to one specified by the root user. Any resources outside of the chrooted environment ("jail" or "cage") would be inaccessible to that user. Obviously, chroot can be broken if the user gains root access, so this is not entirely fool-proof. However, chroot can make things very difficult for an attacker; and that's what we like. Some popular uses for chroot involve setting daemons to run inside a chrooted cage. With SSH version 2.1.0, SSH Communications Security introduced the ChRootGroups feature; which provides a quick and easy way for administrators to lock users inside a chrooted cage.
Thus far, chroot has not been widely used for creating secure user environments; the difficulties involved with creating a functional cage are an obstacle that still needs to be overcome. Of course, there are limitations to ChRootGroups. Making It Work #! Breaking out of a chroot() padded cell. This page details how the chroot() system call can be used to provide an additional layer of security when running untrusted programs. It also details how this additional layer of security can be circumvented. chroot() is a Unix system call that is often used to provide an additional layer of security when untrusted programs are run. The kernel on Unix varients which support chroot() maintain a note of the root directory each process on the system has. Generally this is "/", but the chroot() system call can change this.
When chroot() is successfully called, the calling process has its idea of the root directory changed to the directory given as the argument to chroot(). For example after the following line of code, the process would see the directory "/foo/bar" as its root directory. chdir("/foo/bar"); chroot("/foo/bar"); Note the use of the chdir() call before the chroot() call. It should be noted that the more complex and larger a program gets, the more support files it will use.
» SFTP with chroot jail on CentOS. Secure FTP uses openssh and was engineered by the IETF between 2001 and 2007. It has the potential to replace the insecure and older File Transfer Protocol (FTP). Another alternative to FTP and SFTP is WebDAV, which uses HTTP/TCP pipelining technology and hence does considerably speed up file transfers. However if you wanted WebDAV to be secure you would have to go through the hassles of creating a working SSL connection. This article will focus on implementing a SFTP Chroot Jail for SFTP usage.
It has been last updated in October 2013 to incorporate some of the suggestions by the readers in the comments. SFTP should work out of the box if SSH is already running on your server. Just connect from your client machine with sftp user@hostname.tld The SFTP connection itself is getting tunneled over SSH. To achieve a simple chroot jail, software-wise you need openSSH 5 or greater. At the time of this blog post (Nov 2010), CentOS 5.5 still shipped with the one-year old openSSH 4.6. How to build a chroot jail environment for CentOS :: Things n' Stuff. A chroot environment is simply a directory – inside which you can find a file system hierarchy exactly like your original operating system. You can then use the UNIX chroot command to open a shell in that directory so that command running under that shell see only the chroot environment and can’t mess up your system.
This is very useful for many different reasons – for example if you want to build some software packages and you don’t want their build dependencies to pollute your real system. Building a chroot environment is not difficult at all using the right tools, and YUM – the CentOS installation tool – has what you need. To start, log into your CentOS system and create yourself a directory where you want to build your chroot jail. I usually choose something like /var/tmp/chroot, so I would run mkdir -p /var/tmp/chroot Finally we can call on YUM to install the rest of our system: yum --installroot=/var/tmp/chroot install -y rpm-build yum Optional The special file systems Network.