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How to Fix "Weak Crypto is Allowed" in Samba » History » Version 7

Gareth Eaton, 12/18/2023 12:48 AM

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h1. How to Fix "Weak Crypto is Allowed" in Samba
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The "Weak crypto is allowed" message from testparm in Samba is a known issue. It often appears due to internal checks related to cryptographic methods and does not necessarily indicate a significant security flaw in your configuration. 
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Ensuring strong security in Samba can be achieved by using SMB3 and carefully managing authentication methods.
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1. Open the Samba configuration file, usually located at `/etc/samba/smb.conf`, with a text editor. Use a command like `sudo nano /etc/samba/smb.conf`.
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2. Inside the `smb.conf` file, find the *`[global]` section* , where you can configure global settings for Samba.
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3. Add or modify the following lines in the `[global]` section:
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<pre>
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   server min protocol = SMB3
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   server max protocol = SMB3
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   ntlm auth = ntlmv2-only
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</pre>
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These settings ensure that Samba uses a secure protocol (SMB3.02) and enables NTLM authentication while disabling weaker LANMAN authentication.
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4. Save the changes and exit the text editor.
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5. Restart the Samba service to apply the new configuration. Use a command like `sudo systemctl restart smbd` (command may vary depending on your Linux distribution).