Smb session authentication failure

1. What is Event 551 SMB session authentication failure?
2. What is the reason for 4625 failure?
3. What is Event ID 4625 0xC000006D?
4. What is SMB authentication?
5. How do I turn off SMB authentication?
6. What is Event ID 4625 logon Type 5?
7. What is event ID 4627?
8. What is event ID 4648?
9. What is a SMB session?
10. Why is SMB not signing required?
11. What happens if SMB signing is disabled?
12. What happens if SMB is disabled?
13. Why is SMB not signing required?
14. How do I fix Kerberos error?
15. Is SMB signing necessary?
16. How do you check if SMB signing is enabled?

What is Event 551 SMB session authentication failure?

This indicates that the client is not providing a user name (and domain credentials, if necessary). By default, Windows Server denies anonymous access to shares. This error does not always indicate a problem with authorization, but mainly authentication. It is more common with non-Windows clients.

What is the reason for 4625 failure?

Examples of 4625

Failure Reason: Unknown user name or bad password. This event is generated when a logon request fails. It is generated on the computer where access was attempted. The Subject fields indicate the account on the local system which requested the logon.

What is Event ID 4625 0xC000006D?

0xC000006D: this is either due to a bad username or authentication information. As for Event Event log 4625, we could refer to the following article: 4625(F): An account failed to log on.

What is SMB authentication?

SMB provides an authenticated intercommunication process mechanism to share the files or resources (files, folders, printers) within the server. SMB provides the clients to edit files, delete them, share the files, browse the network, print services, etc., over the network.

How do I turn off SMB authentication?

Under Control Panel Home, select Turn Windows features on or off to open the Windows Features box. In the Windows Features box, scroll down the list, clear the check box for SMB 1.0/CIFS File Sharing Support and select OK. After Windows applies the change, on the confirmation page, select Restart now.

What is Event ID 4625 logon Type 5?

When Audit Failure logon event (4625) is registered with logon type = 5, this commonly means that the “designated” user has changed password, and you should update service logon details. Logon type 7: Unlock.

What is event ID 4627?

Event 4627 is generated along with event 4624 (successful account logon) and shows the entire list of groups that the particular logged-on account belongs to. If all the security information cannot be fit into a single security audit event, multiple events are generated.

What is event ID 4648?

This event is generated when a process attempts an account logon by explicitly specifying that account's credentials. This most commonly occurs in batch-type configurations such as scheduled tasks, or when using the “RUNAS” command.

What is a SMB session?

The Server Message Block protocol (SMB protocol) is a client-server communication protocol used for sharing access to files, printers, serial ports and other resources on a network. It can also carry transaction protocols for interprocess communication.

Why is SMB not signing required?

This system enables, but does not require SMB signing. SMB signing allows the recipient of SMB packets to confirm their authenticity and helps prevent man in the middle attacks against SMB. SMB signing can be configured in one of three ways: disabled entirely (least secure), enabled, and required (most secure).

What happens if SMB signing is disabled?

Summary: Signing is disabled on the remote SMB server. This can allow man-in-the-middle attacks against the SMB server. SMB servers should both require signatures as well as support them.

What happens if SMB is disabled?

Disabling SMBv1 without thoroughly testing for SMBv1 traffic in your environment can have unintended consequences, up to and including a complete suspension of all network services, denied access to all resources, and remote authentication failures (like LDAP).

Why is SMB not signing required?

This system enables, but does not require SMB signing. SMB signing allows the recipient of SMB packets to confirm their authenticity and helps prevent man in the middle attacks against SMB. SMB signing can be configured in one of three ways: disabled entirely (least secure), enabled, and required (most secure).

How do I fix Kerberos error?

Resolution. To resolve this problem, update the registry on each computer that participates in the Kerberos authentication process, including the client computers. We recommend that you update all of your Windows-based systems, especially if your users have to log on across multiple domains or forests.

Is SMB signing necessary?

If you are not using SMB signing, then you are at risk for your SMB traffic to be man-in-the-middled. This means that an internal attacker is able to essentially steal all share sessions that are active on your network.

How do you check if SMB signing is enabled?

From the Start menu, search for msc. Set Microsoft network client to “Enabled” for “Digitally sign communications (always)” and the Microsoft network server “Digitally sign communications (always).” If on a local system, reboot the computer and use Nmap to validate that SMB2 signing is required.