Key

GNU/Linux OpenSSH QuickRef

/ GNU/Linux /

LocalForward/Dynamic tunnels & SFTP jumphost connection examples (commandline):

>ssh -L 1522:remote.hostname:1522 user@tunnel.hostname
>ssh -D 8080 user@tunnel.hostname
>sftp -o ProxyJump=user@jump.hostname:22 [-b ./batch.scr] user@dest.host.internal

LocalForward/Dynamic tunnels & SFTP jumphost connection examples (commandline and config):

>ssh dsthst

~/.ssh/config:
Host prxjmp
  Hostname jump.hostname
  Port 22
  User user
  LocalForward 7080 10.0.0.9:7080
  DynamicForward 8080
Host dsthst
  HostName dest.host.internal
  Port 22
  User user
  ProxyJump prxjmp
  IdentityFile ~/.ssh/other_key_location

Generate a SSH Key Pair:

>ssh-keygen -m PEM -t ecdsa -b 521
>ssh-keygen -m PEM -t ecdsa -b 521 -C "tim" -f /home/tim/tmp/id_ecdsa

Other algorithms:

>ssh-keygen -t ed25519
>ssh-keygen -t dsa 
>ssh-keygen -t rsa -b 4096

Convert SSH2 Public Key to OpenSSH Public Key

>ssh-keygen -i -f id_ssh2.pub [-m PKCS8]

Convert OpenSSH Public Key to SSH2 Public Key

>ssh-keygen -e -f id_openssh.pub

Get Key Fingerprint MD5

ssh-keyscan -p [port] [hostname] > [hostkeyfpfile]
ssh-keygen -l -f [hostkeyfpfile] -E md5

Start session with alternate key

sftp -o IdentityFile=/home/tim/.ssh/id_rsa_2 tim@server1

Implement group restrictions in /etc/ssh/sshd_config

# Group restrictions 
AllowGroups sshaccess

Match Group sshpubkeyonly
      PasswordAuthentication no

Match group sftpusers
    X11Forwarding no
    ChrootDirectory %h
    AllowTcpForwarding no
    ForceCommand internal-sftp

MSSQL Configure Database Encryption

/ MSSQL Server /

Configure database encryption and backup keys en certificates. This manual shows the complete chain from Service Master Key to the Database Encryption Key. Please remember to at least backup the Server Certificate (marked: “[*** IMPORTANT ***]”) and store these files in a secure location. Without this certificate you cannot access your data when it’s moved or restored to another server. You should substitute all (random generated) passwords with your own.

STEP 1 – Backup and restore (for verification purposes) Service Master Key.

USE master;
GO

-- Backup Service Master Key...
BACKUP SERVICE MASTER KEY TO FILE = 'X:\Path\To\ServiceMaster.key' 
ENCRYPTION BY PASSWORD = 'ooxuRai4shaid0AvnieLoh6t'

-- Restore Service Master Key...
RESTORE SERVICE MASTER KEY FROM FILE = 'X:\Path\To\ServiceMaster.key' 
DECRYPTION BY PASSWORD = 'ooxuRai4shaid0AvnieLoh6t' FORCE

STEP 2 – Create, backup and restore (for verification purposes) Database Master Key and Server Certificate.

USE master;
GO

-- Create Database Master Key...
CREATE MASTER KEY ENCRYPTION BY PASSWORD = 'eeLohz8iJuapo5mekohng0Ah';
GO

-- Backup Database Master Key...
BACKUP MASTER KEY TO FILE = 'X:\Path\To\Master.key'
ENCRYPTION BY PASSWORD = 'eeLohz8iJuapo5mekohng0Ah'
GO

-- Drop Database Master Key for restore test...
DROP MASTER KEY
GO

-- Restore Database Master Key...
RESTORE MASTER KEY FROM FILE = 'X:\Path\To\Master.key' 
DECRYPTION BY PASSWORD = 'eeLohz8iJuapo5mekohng0Ah'
ENCRYPTION BY PASSWORD = 'eeLohz8iJuapo5mekohng0Ah'
GO

-- Open key and let Service Master Key decrypt (for transparent encryption)...
OPEN MASTER KEY DECRYPTION BY PASSWORD = 'eeLohz8iJuapo5mekohng0Ah'
GO
ALTER MASTER KEY ADD ENCRYPTION BY SERVICE MASTER KEY
GO

-- Create Server Certificate...
CREATE CERTIFICATE ServerCertDefault WITH SUBJECT = 'Server Certificate Default'
GO

-- Backup Server Certificate and Key [*** IMPORTANT ***]...
BACKUP CERTIFICATE ServerCertDefault TO FILE = 'X:\Path\To\ServerCertDefault.cer'
WITH PRIVATE KEY ( FILE = 'X:\Path\To\ServerCertDefault.key', 
ENCRYPTION BY PASSWORD = 'Eeh3aeb0EiTh2ohZneil8ueS' );
GO

-- Remove Server Certificate for restore test....
DROP CERTIFICATE ServerCertDefault
GO

-- Restore Server Certificate with Key...
CREATE CERTIFICATE ServerCertDefault 
FROM FILE = 'X:\Path\To\ServerCertDefault.cer'
WITH PRIVATE KEY ( FILE = 'X:\Path\To\ServerCertDefault.key' , 
DECRYPTION BY PASSWORD = 'Eeh3aeb0EiTh2ohZneil8ueS' );
GO

STEP 3 – Turn on database encryption in database.

USE [Database]
GO

-- Create Database Encryption Key...
CREATE DATABASE ENCRYPTION KEY WITH ALGORITHM = AES_128
ENCRYPTION BY SERVER CERTIFICATE ServerCertDefault
GO

-- Enable Encryption...
ALTER DATABASE [Database] SET ENCRYPTION ON
GO

-- Check if database encryption is turned on...
SELECT name, is_encrypted FROM sys.databases WHERE is_encrypted = 1

Results:
name                                                           is_encrypted
-------------------------------------------------------------- ------------
DatabaseName                                                   1