Windows Event ID 4625: Failed Logon Analysis

Monitoring and analyzing failed logon attempts regularly is crucial for maintaining a secure IT environment. Windows Event ID 4625 is a security event log that gets triggered by these failed logon attempts. By examining and connecting the dots between these events, we can uncover vital information about the potential security threats, such as brute force attacks and unauthorized access, among others.

What is Event ID 4625?

The Windows security log keeps track of failed logon attempts, which are recorded as event ID 4625. For instance, the Windows auditing system—this is the key player that generates these events, is crucial for spotting and addressing security issues. The event log contains all the necessary details about the failed logon attempt, including the account name, workstation name and the reason behind the failure.

Analyzing Event ID 4625

• Step 1: Collecting Event Logs: To analyze Event ID 4625, you have 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, please filter them to display only Event ID 4625. Then sorting the logs by time, account name, or workstation name can help you to identify patterns or repeated failed attempts.
• Step 3: Identifying Patterns: Please check the patterns in the failed logon attempts. Common patterns include:

• • If you see multiple failed login attempts from the same account, it might be a sign of a brute force attack.
  • If you see multiple failed attempts from different accounts, it could mean that there's a bigger attack aimed at several users.
  • Logon attempts from unexpected IP addresses or geographic locations could indicate unauthorized access attempts.

• Step 4: Investigating the Source: To figure out where those failed logon attempts are coming from, start by checking the workstation name and the network details. This will help you identify the source of the attempts. If it turns out to be an external source, you might want to think about blocking that IP address or putting some extra security measures in place.

Common Causes

• Incorrect Username or Password: This is the most frequent reason for the event id 4625. The user may have simply mistyped their credentials.
• Account Disabled or Locked: if the user account is disabled by the administrator or locked due to multiple failed login attempts, they we get 4625 event id. 
• 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: When there are problems with the network connection, it can lead to login failures.
• Malware or Compromised Credentials: Also, malware or compromised credentials could be the cause of failed login attempts.

Best Practices for Managing Event ID 4625

1. Regular Monitoring: Regularly checking and reviewing Event ID 4625 logs is crucial for spotting and addressing any potential security threats quickly.

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

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

4. Enable Multi-Factor Authentication (MFA): Please 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: It determines 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 an important security event that sheds light on failed logon attempts. By diving into this event, organizations can better spot and tackle potential security threats. Keeping an eye on these events, following best practices, and taking proactive steps can greatly boost the security of Windows environments and help fend off unauthorized access attempts.

Event ID 4625 isn’t just another log entry, it’s an essential resource for IT professionals and security teams who are dedicated to protecting their systems from cyber threats. By diving into the insights provided by these events, organizations can strengthen their defenses and ensure they maintain a strong security stance.

Relevant Article

• Windows Event ID 4740: Account Lockout Analysis