Windows Event ID 4625: Failed Logon Analysis

Monitoring and analyzing periodically failed logon attempts is one of the essential processes to have a secure environment. Windows Event ID 4625 is a security event log generated by failed logon attempts. By studying and correlating these events, we can gain essential information regarding security threats like brute force attacks, unauthorized access, and more.

What is Event ID 4625?

The Windows security log captures failed logon attempts as event ID 4625. For example, Windows auditing system, which is the main system that generates this type of event, is one of the most important systems to identify and respond to security incidents. The event log provides all the details related to the failed logon attempt, such as the account name, workstation name, and the reason for the failure.

Analyzing Event ID 4625

• Step 1: Collecting Event Logs: To analyze Event ID 4625, you need to collect the relevant event logs from the Windows Security log. This can be done using the Event Viewer or through PowerShell commands.
• Step 2: Filtering and Sorting: Once the logs are collected, filter them to display only Event ID 4625. Sorting the logs by time, account name, or workstation name can help identify patterns or repeated failed attempts.
• Step 3: Identifying Patterns: Look for patterns in the failed logon attempts. Common patterns include:

• • Multiple failed attempts from the same account: This could indicate a brute force attack.

  • Failed attempts from multiple accounts: This might suggest a broader attack targeting multiple users.

  • Failed attempts from unusual locations: Logon attempts from unexpected IP addresses or geographic locations could indicate unauthorized access attempts.

• Step 4: Investigating the Source: Determine the source of the failed logon attempts. Check the workstation name and network information to identify the origin of the attempts. If the source is external, consider blocking the IP address or implementing additional security measures.

Common Causes

• Incorrect Username or Password: This is the most frequent reason. The user may have simply mistyped their credentials.
• Account Disabled or Locked: The user account might be disabled by the administrator or locked due to multiple failed login attempts.
• Account Expiration: The user's account may have expired.
• Account Policy Restrictions: There might be restrictions on the account that prevent login from the specific source or time.
• Network Connectivity Issues: Problems with the network connection can also cause login failures.
• Malware or Compromised Credentials: In some cases, malware or compromised credentials could be the cause of failed login attempts.

Best Practices for Managing Event ID 4625

1. Regular Monitoring: Regularly monitor and review Event ID 4625 logs to detect and respond to potential security threats promptly.

2. Implement Account Lockout Policies: Configure account lockout policies to automatically lock accounts after a specified number of failed logon attempts.

3. Use Strong Passwords: Enforce strong password policies to reduce the risk of successful brute force attacks.

4. Enable Multi-Factor Authentication (MFA): Implement MFA to add an additional layer of security, making it more difficult for attackers to gain access.

5. Educate Users: Educate users about the importance of strong passwords and recognizing phishing attempts to reduce the likelihood of compromised credentials.

Investigating Failed Login Attempts

When investigating Event ID 4625, it's important to consider the following:

• Frequency: A single failed attempt is usually not a concern, but multiple attempts from the same source or for the same account should be investigated.
• Source: Determine the source of the login attempt (local, network, remote).
• Account: Identify the account that failed to log in.
• Time: Note the time of the failed attempt.
• Logon Type: Determine the type of logon attempt (interactive, network, service).
• Failure Reason: Examine the specific reason for the failure (incorrect password, account disabled, etc.).

Windows Event ID 4625 is a critical security event that provides valuable information about failed logon attempts. By understanding and analyzing this event, organizations can detect and respond to potential security threats more effectively. Regular monitoring, implementing best practices, and taking proactive measures can significantly enhance the security of Windows environments and protect against unauthorized access attempts.

Event ID 4625 is not just a log entry; it is a vital tool in the arsenal of IT professionals and security teams tasked with safeguarding their systems from malicious actors. By leveraging the insights gained from analyzing these events, organizations can fortify their defenses and maintain a robust security posture.

Relevant Article

• Windows Event ID 4740: Account Lockout Analysis