Secure-FTP-Backup

Create secure high encrypted FTP backups. This script creates backups which are encrypted with GnuPG and are then sent to a FTP server. It should be used if you place your backups on an unsecure FTP server. As the backups are already encrypted on the server, you don't need to worry if the backups are unsecurely transfered (FTP instead FTPS). It checks too if there is still enough space free on the FTP server. If not it deletes the oldest files that there is exactly enough space available. As default encryption software GnuPG will be used which automatically compress the archived files. It can too backuping a full root / filesystem.

CONFIGURATION EXAMPLE FILE

ftp-backup.conf file:

# Secure FTP Backup Configuration File

# FTP host settings
ftp_host=hostname
ftp_port=21
ftp_user=user
ftp_password=password
# Maximum available space on the remote FTP server (defined in bytes)
ftp_quota=100000000000

# Backup directories with their absolute paths
# Multiple directories can be written with semicolons ';'
backup_dirs=/home/user1;/home/user2

# Prefix for the backup file names
prefix=yourhostname.tld_backup_

# GnuPG encryption settings
encryption_cmd=/usr/bin/gpg
encryption_key_name=Secure FTP Backup - yourhostname.tld

# Mandatory programs
ftp_cmd=/usr/bin/ftp
cut_cmd=/usr/bin/cut
awk_cmd=/usr/bin/awk
archive_cmd=/bin/tar

HOW TO USE IT

Run as root:

$ ftp-backup.php /etc/ftp-backup.conf

Simply add this in your cronjob file /etc/crontab:

0 5 * * * root /usr/local/bin/ftp-backup.php /etc/ftp-backup.conf > /dev/null 2>&1

REQUIREMENTS

• PHP 5
• GnuPG
• ftp command line tool
• tar command line tool
• awk
• FTP server access
• UNIX compatible operating system

INSTALLATION

Configure the encryption by creating a new GnuPG secret and public key on secret and protected computer:

$ gpg --gen-key

• Choose 4096 bits key length, to have today the strongest possible key length, as your key could not be cracked so early in future as compute power is increasing all the time.

• Use a passphrase which you would need to decrypt your data

• As full name choose for example "Secure FTP Backup - yourhostname.tld", as the backup script will match exactly this name of encryption_key_name configuration field

• For the email address, you can put yours if you like, its not mandatory

• Backup your private GPG key on a secure place (it should not be your FTP backup space server). Use the command:

  $ gpg --export-secret-keys

After the configuration, check that your key has been created:

# gpg --list-key
/root/.gnupg/pubring.gpg
------------------------
pub   4096R/CEB34505 2013-12-26
uid                  Secure FTP Backup - host.domain.tld <[email protected]>
sub   4096R/B9B80850 2013-12-26

Copy the public key of this key on your server where you would like to backup your files:

    $ gpg --armor --export 'Secure FTP Backup - yourhostname.tld' > yourhostname.tld.pub

Import the key on your server where you would like to backup your files. Trust this key.

    $ gpg --import < yourhostname.tld.pub
    $ gpg --edit-key 'Secure FTP Backup - yourhostname.tld'
    gpg> trust
    Your decision? 5
    Do you really want to set this key to ultimate trust? (y/N) y
    gpg> quit

Copy script file to /usr/local/bin/ftp-backup.php and set file to be executable:

$ cp ftp-backup.php /usr/local/bin
$ chmod 755 /usr/local/bin/ftp-backup.php

Copy and configure the configuration file at /etc/ftp-backup.conf Try if it works by executing as root:

$ ftp-backup.php /etc/ftp-backup.conf

Add a crontab entry in /etc/crontab:

# Secure FTP Backup
0 5 * * * root /usr/local/bin/ftp-backup.php /etc/ftp-backup.conf > /dev/null 2>&1

Restart cron:

$ /etc/init.d/cron restart

You can check your /var/log/syslog log file to see if the script executed successfully.

DECRYPTING & EXTRACTING

Log on the FTP server, download the encrypted compressed archived file. Decrypt, uncompress and unarchive it:

$ gpg -d /tmp/backup_20131225_21\:03\:31.tar.gpg | tar xfv -

The output of GnuPG would be similar to that:

gpg: encrypted with 4096-bit ELG-E key, ID 2B362D79, created 2013-12-25
      "Secure FTP Backup <[email protected]>"

NOTE

The script can not parse sub directories of the FTP service to count the taken quota space. It can only count the bytes of the files which are in the main directory of the backup FTP service.

VERSION

1.1

LICENSE

The MIT License (MIT)

AUTHOR

Stephan Ferraro - email: [email protected] - created in december 2013 at Germany