SQL Server

SSH Host Key Fingerprint

Demonstrates getting the SSH server's host key fingerprint after connecting. The HostKeyFingerprint property returns the classic MD5 form, while GetHostKeyFP returns a fingerprint using a chosen hash algorithm, with optional inclusion of the key type and hash name.

Background: The host key fingerprint identifies the server, and comparing it against a known-good value is how a client implements host-key pinning — detecting a man-in-the-middle or a server whose key has changed. This is the same fingerprint an SSH client shows on first connection when it asks whether to trust the host. Prefer SHA256, which is the modern standard; MD5 fingerprints still appear in older tooling but are cryptographically weak.

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-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  This example requires the Chilkat API to have been previously unlocked.
    --  See Global Unlock Sample for sample code.

    --  Demonstrates getting the SSH server's host key fingerprint after connecting.

    DECLARE @ssh int
    EXEC @hr = sp_OACreate 'Chilkat.Ssh', @ssh OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @hostname nvarchar(4000)
    SELECT @hostname = 'ssh.example.com'
    DECLARE @port int
    SELECT @port = 22
    EXEC sp_OAMethod @ssh, 'Connect', @success OUT, @hostname, @port
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @ssh, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh
        RETURN
      END

    --  The classic MD5 fingerprint is available as a property.
    DECLARE @md5_fingerprint nvarchar(4000)
    EXEC sp_OAGetProperty @ssh, 'HostKeyFingerprint', @md5_fingerprint OUT

    PRINT @md5_fingerprint
    --  For example:  ssh-rsa 3072 21:b0:d8:41:4e:ef:78:10:20:af:01:b7:71:5d:eb:94

    --  GetHostKeyFP returns a fingerprint using the hash algorithm of your choice, such as SHA256,
    --  SHA384, or SHA512.  The 2nd and 3rd arguments control whether the key type and the hash name
    --  are included in the returned string.
    DECLARE @includeKeyType int
    SELECT @includeKeyType = 1
    DECLARE @includeHashName int
    SELECT @includeHashName = 1
    DECLARE @sha256_fingerprint nvarchar(4000)
    EXEC sp_OAMethod @ssh, 'GetHostKeyFP', @sha256_fingerprint OUT, 'SHA256', @includeKeyType, @includeHashName
    EXEC sp_OAGetProperty @ssh, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ssh, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh
        RETURN
      END

    PRINT @sha256_fingerprint
    --  ssh-rsa SHA256:Ufgj480OsdsCZRjj9sSNM6fpgIcSJ61RsIG8usndUIY=

    SELECT @includeKeyType = 0
    SELECT @includeHashName = 1
    EXEC sp_OAMethod @ssh, 'GetHostKeyFP', @sha256_fingerprint OUT, 'SHA256', @includeKeyType, @includeHashName
    EXEC sp_OAGetProperty @ssh, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ssh, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh
        RETURN
      END

    PRINT @sha256_fingerprint
    --  SHA256:Ufgj480OsdsCZRjj9sSNM6fpgIcSJ61RsIG8usndUIY=

    SELECT @includeKeyType = 1
    SELECT @includeHashName = 0
    EXEC sp_OAMethod @ssh, 'GetHostKeyFP', @sha256_fingerprint OUT, 'SHA256', @includeKeyType, @includeHashName
    EXEC sp_OAGetProperty @ssh, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ssh, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh
        RETURN
      END

    PRINT @sha256_fingerprint
    --  ssh-rsa Ufgj480OsdsCZRjj9sSNM6fpgIcSJ61RsIG8usndUIY=

    SELECT @includeKeyType = 0
    SELECT @includeHashName = 0
    EXEC sp_OAMethod @ssh, 'GetHostKeyFP', @sha256_fingerprint OUT, 'SHA256', @includeKeyType, @includeHashName
    EXEC sp_OAGetProperty @ssh, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @ssh, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @ssh
        RETURN
      END

    PRINT @sha256_fingerprint
    --  Ufgj480OsdsCZRjj9sSNM6fpgIcSJ61RsIG8usndUIY=

    EXEC sp_OAMethod @ssh, 'Disconnect', NULL

    EXEC @hr = sp_OADestroy @ssh


END
GO