[DBNETLIB] [ConnectionOpen (SECDoClientHandshake()).] SSL Security Error – How to Resolve

This article, suggests a way of resolving the below error message, when you are trying to access SQL Server using “Microsoft OLE DB Provider for SQL Server” and TLS 1.0: [DBNETLIB] [ConnectionOpen (SECDoClientHandshake()).] SSL Security Error

Prior to start writing this article, I was thinking of using a title like “How to still use TLS 1.0”, or something similar, but besides the fact that would have given a wrong message, it would not help so much because many people, usually search for such articles using the error message (SSL Security error)…

So, I anticipate that this article, with this title, would help as many people as possible 🙂

Drop me a line if you find the article useful and why not, subscribe to my newsletter to stay up to date with future articles!


A Few Words About TLS 1.0

TLS 1.0 is considered a deprecated protocol and it is not recommended anymore to be used to secure connections. That’s why many organizations (if not all) transitioned or are in the process of transitioning to newer versions of TLS such as TLS1.1 or above.

However, you may still encounter outdated applications that still need to use this protocol, even for a while for just performing a single operation. One such example, is to try and connect to a SQL Server instance via Microsoft OLE DB Driver for SQL Server using TLS 1.0.

If you are in such situation, I have good news, from a technical aspect, it is still possible to do this.

Read on to learn more.


SQL Server Support for TLS 1.0 and Above

SQL Server still supports all TLS protocols, currently from 1.0 to 1.2. However, depending on the version of SQL Server you have, especially in cases of older SQL Server versions, you might need a patch.

Read this article on SQLNetHub to learn more about SQL Server support for TLS versions.


How to Resolve the [ConnectionOpen (SECDoClientHandshake()).] SSL Security Error

Now let’s jump to the juicy part of this article and see how finally we can resolve the above error and manage to connect to SQL Server using Microsoft OLE DB Driver for SQL Server and TLS 1.0.

Note that if you are just trying to connect with TLS 1.0 for a while in order to perform a specific task, then make sure to revert the below changes in order to restore the security level of your systems back to their previous level.


Latest Microsoft OLE DB Driver for SQL Server

The first step towards resolving the SSL Security error, is to make sure that the version of the target SQL Server instance you want to connect to, is supported by the driver.

For example, Microsoft OLE DB Driver 18.1 for SQL Server supports connecting to SQL Server 2012 or later.

For older versions of SQL Server, you will need to find an earlier version of Microsoft OLE DB Provider for SQL Server as well.

You can find the latest version of the OLE DB driver here.


Useful details:

The Microsoft OLE DB Provider for SQL Server, allows ADO to access Microsoft SQL Server. However, This is an older driver and it is not recommended to be used driver for new development, since it is deprecated.

The new OLE DB provider is called the Microsoft OLE DB Driver for SQL Server (MSOLEDBSQL) which will be updated with the most recent server features going forward (learn more)


Registry Changes

The next step is, to edit the Windows Registry (always be careful when messing up with Windows Registry – only certified engineers should do that).

To enable TLS 1.0 in Windows

In Windows Registry, add the below dword keys:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Server]

  • “Enabled”=dword:00000001
  • “DisabledByDefault”=dword:00000000


[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.0\Client]

  • “Enabled”=dword:00000001
  • “DisabledByDefault”=dword:00000000


To disable TLS 1.0 in Windows

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Server]

  • “Enabled”=dword:00000000
  • “DisabledByDefault”=dword:00000001

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.1\Client]

  • “Enabled”=dword:00000000
  • “DisabledByDefault”=dword:00000001

Learn more about the above registry changes in this MS Docs article.


Local Security Policy

The next step is to check the Local Security Policy on the database server.

So, in Local Security Policy on the Database Server, make sure that the setting “System Cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing” is disabled.

If you want to learn more about this security option, you can check this MS Docs article.


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Server Protocols, Ciphers, Hashes and Client Protocols

The last step in this troubleshooting guide, is to use IISCrypto, which is an excellent free tool, that allows you to control which protocols, ciphers, and more are enabled (or not) on a Windows server.

That being set, you will need to run IISCrypto and make sure that the “TLS 1.0” Server and Client Protocols, as well as the”SHA” hash are enabled.

Here’s a screenshot of IISCrypto, running on my PC, having TLS 1.0 and “SHA” enabled for illustration purposes:

[DBNETLIB] [ConnectionOpen (SECDoClientHandshake()).] SSL Security Error - How to Resolve - Article on SQLNetHub

Note that, if finally you need to perform any changes using IISCrypto, you will need to restart the server.

Actually, for any changes you might need to perform, it is recommended to restart the server.


A Piece of Advice

As mentioned in this article’s beginning, TLS 1.0 is considered a deprecated protocol and it is not recommended anymore to be used to secure connections.

Instead, you should be using newer versions of TLS.

In case you just need to switch to TLS 1.0 for performing an ad hoc task, you need to make sure that after you completed the task, you revoked any changes you might have applied, and disable again TLS 1.0 and the “SHA” hash.


See More

Check out DBA Security Advisor, a SQL Server security tool to assess your SQL Server instances against a rich set of security checks and get security best practice recommendations.



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Reference: SQLNetHub.com (https://www.sqlnethub.com)

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