/software/ssh/

This example will show how to convert the OpenSSH key format to ssh.com (Tectia enterprise products) key format. It will also show you how to import the converted keys into ssh.com's Secure File Transfer Client.

1. Copy your private OpenSSH key from your unix system to your local windows machine. The private key is in your home dir ~/.ssh/. Usually it's called id_(something) like id_dsa. I'm going to call mine id_dsa for this example. Make sure your copy the file by transferring it over the network with scp/sftp, shared mount point you have to your your windows machine, or usb key. DO NOT cat the file in a terminal and then copy and paste it into a text editor on the windows machine. This will not work because of the differences in file formats of unix and windows.

2. Go and download Putty. Get the zip version from the website and unzip it. Find the program puttygen.exe in the unzipped files and execute it.

3. Click the "load" button. Select "files of all type" drop down. Then select all files. Point puttygen to your OpenSSH key that you copied over in step 1. Then click "open". Enter your keys pass phrase (If you have one. You should be using pass phrases on your keys.).

4. Click conversions->export->ssh.com key. Then save your converted private key with the name "id_dsa_sshcom". This is your converted private key. Names are important to the ssh.com program when importing keys. The key pair has to have matching names to be imported. You can call it anything you want but it has to take the format: key_name and key_name.pub.

5. Now click file->save public key. Save the public key with the name id_dsa_sshcom.pub in the same area (folder) you saved your private key in step 4. This is your public key that goes with your private key. Make sure the first part of the names match.

6. Open the ssh.com Secure File Transfer Client. Click edit->settings. Then go to user authentication->keys (in the left pane). Click the import button. Select "files of all type" drop down. Then select all files. Click the "Look in" drop down and point it to the folder where your "id_dsa_sshcom.pub" and "id_dsa_sshcom" files are. Select your public key id_dsa_sshcom.pub and click ok. Then ok out of the settings area. FYI: The ssh.com client will ask for the public key and then when it is selected is will match the private key that goes with it by the same name. Just without the .pub at the end.

7. Now you should be able to connect to any host that you have put your public keys on with ssh.com's Secure File Transfer Client.

8. After you have tested your connection make sure you delete your private key you copied over from your system when we started.

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This is an install of OpenSSH from source on CentOS 4.5. It is not so much of an upgrade as it is a seperate install. SSH is your gateway into your machine. It is the access point for your machine over the network. Therefore it needs one of the most secure parts of your system. When a vulnerability comes out for it you have to update it ASAP. Problem is most distros don't make haste in getting packages out that update it. So your stuck with updating it yourself. So that rpm or deb package you installed is useless now that is vulnerable.

So what we are going to do is compile and install our own OpenSSH in the /opt tree (or wherever you want). Then whenever OpenSSL, OpenSSH, or Zlib have a security problem we can just quickly patch, recompile, and install a new version of any of them. No dependence on the distro's packages and their slower response times. The install below is what versions of the packages where avaliable at the time so change those accordingly.

First we download and install zlib. It does not seem to change version much so you might not need to do this each time.

cd /tmp
mkdir -p /opt/zlib
mkdir zlib1.23
cd zlib1.23/
wget http://www.zlib.net/zlib123.zip
unzip zlib123.zip
make
make install prefix=/opt/zlib/

Next we download and install OpenSSL.

cd /tmp
mkdir -p /opt/openssl
wget http://www.openssl.org/source/openssl-0.9.8e.tar.gz
tar xvzf openssl-0.9.8e.tar.gz
cd openssl-0.9.8e
./config --prefix=/opt/openssl --openssldir=/opt/openssl
make
make test
make install

Now we download and install OpenSSH. This version is for linux so it will come from the portable code base. In the configure section we are pointing to the OpenSSL and zlib installs we did above. You also want to check to see where your xauth file is and put that path in accordingly. I just did the command "which xauth" and got the path but you might need to do a "find / -name xauth" to find it.

cd /tmp
mkdir -p /opt/openssh
wget ftp://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-4.7p1.tar.gz
tar xvzf openssh-4.7p1.tar.gz
cd openssh-4.7p1
./configure --prefix=/opt/openssh --with-ssl-dir=/opt/openssl --with-xauth=/usr/X11R6/bin/xauth --with-zlib=/opt/zlib
make
make install

We are going to use the SSHD init.d script to start and stop our version of SSH. This script comes with CentOS 4.5. To use it we need to change some paths. Check /etc/init.d/sshd make sure these point to /opt/openssh.

# Some functions to make the below more readable
KEYGEN=/opt/openssh/bin/ssh-keygen
SSHD=/opt/openssh/sbin/sshd
RSA1_KEY=/opt/openssh/etc/ssh_host_key
RSA_KEY=/opt/openssh/etc/ssh_host_rsa_key
DSA_KEY=/opt/openssh/etc/ssh_host_dsa_key

Then restart SSH.

/etc/init.d/sshd restart

Check with telnet that your SSH is giving out the right version number of the one you just installed. You can do this by telnetting to your OpenSSH server.

telnet localhost 22

We should get a response with "OpenSSH_4.7" in the title. The same version that was just installed.

Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
SSH-2.0-OpenSSH_4.7

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