What Does Event ID 4625 Mean in Microsoft-Windows-Security-Auditing: Common Causes and Fixes

These security alerts are your first line of defense against automated attacks and misconfigured systems. 🔍 When you see repeated failed attempts from the same IP, it's often a sign of brute-force activity—something I've personally tracked during Windows deployments in Denver offices.

The event details also help pinpoint whether the issue stems from weak local passwords, expired accounts, or even misconfigured Group Policy settings that prevent legitimate users from accessing resources.

What makes Event ID 4625 particularly valuable is how it distinguishes between different failure types—whether it's an incorrect password, an account lockout, or even a Kerberos pre-authentication failure. This granularity lets administrators quickly identify whether they're dealing with a targeted attack or an internal configuration problem that needs fixing.

In my experience working with Windows 10 rollouts, these logs became our most reliable early warning system for security incidents.

Understanding event ID 4625 security log details

When Windows records a failed logon attempt as Event ID 4625, it captures three critical fields that paint a detailed picture of the security incident.

The Account Name field identifies the user or service account involved, while the Source Network Address reveals the IP address making the attempt—this is your digital fingerprint for tracking attackers.

The Authentication Package tells you which protocol failed (like NTLM or Kerberos), which helps determine if the issue stems from legacy systems or modern authentication methods. These fields work together like a security camera's timestamp, location, and camera angle to reconstruct what happened.

The log also includes a Failure Reason code that ranges from 1 (unknown user) to 12 (account locked out). For example, code 7 typically means "incorrect password," while code 11 indicates "account disabled."

I've seen brute-force attacks where the same IP hits a single account with code 7 150 times in 30 minutes—that's the digital equivalent of someone frantically trying every combination on a lock.

The Logon Type field (like 2 for interactive logon or 10 for remote desktop) helps distinguish between physical attacks at a workstation versus network-based assaults.

What makes this event different from successful logon Event ID 4624 is the absence of a security identifier (SID) in the log details. Successful logins include the user's SID, while failed attempts don't—this is Windows' way of saying "I tried but couldn't verify this identity."

The event also records the Workstation Name (if available), which can reveal if attacks originate from compromised internal machines rather than external IPs.

During a Windows 10 deployment at a Denver office, we once caught an internal workstation infected with malware making 2,347 failed logon attempts against the domain controller in just 24 hours.

Here's what the log fields reveal about common attack patterns:

• Multiple IPs targeting one account: Classic brute-force where attackers cycle through IPs to avoid IP bans (common in credential stuffing attacks)
• Single IP with rapid retries: Automated tools testing leaked credentials (I've seen some hit 5 attempts per second)
• Internal IPs with unusual logon types: Compromised workstations or pass-the-hash attacks moving laterally

One fascinating detail is how Windows tracks the Logon Process field. Values like "Advapi" indicate local logons, while "Kerberos" shows network authentication attempts.

During a security audit at Carnegie Mellon's lab, we discovered an attacker using Logon Process "CredSSP"—a protocol often abused in supply chain attacks where compromised admin tools authenticate with elevated privileges. This field alone can tell you whether you're dealing with a simple password spray or something more sophisticated.

The event's Transmitted Services field reveals which network services the attacker tried to access (like "RPCSS" for remote procedure calls). This helps administrators understand the attacker's intent—were they just probing for valid accounts, or did they have a specific service in mind?

In one case at a Pittsburgh scrapyard repair shop (where my dad used to work), we saw repeated attempts against the WinRM service—a clear sign the attacker was looking for PowerShell access to move laterally through the network.

What most administrators don't realize is how these logs can reveal credential hygiene problems in your organization. If you see Event ID 4625 with Failure Reason 12 (account locked out) for service accounts, it often means someone's using the same password across multiple systems—a classic sign of password reuse.

The key takeaway is that these logs aren't just about catching attackers—they're a mirror reflecting your organization's security posture. 💡

Troubleshooting and resolving failed logon issues

When you see repeated Event ID 4625 entries in your security logs, start by checking the Failure Reason code—this tells you exactly what went wrong. For code 7 (incorrect password), the fix is simple: reset the password using Active Directory Users and Computers or Command Prompt (net user).

If you're seeing code 12 (account locked out), you'll need to unlock the account first with lsadump.py (from Impacket) or through Active Directory Administrative Center. I always recommend testing the fix immediately by attempting a successful logon from a known good device.

For accounts that keep getting locked out, adjust the Account Lockout Policy in Group Policy Editor (gpedit.msc). Look for settings like Account lockout threshold—raising this from 0 (default) to 5 failed attempts gives legitimate users more room for error while still blocking brute-force attacks.

You can also tweak the Reset lockout counter after setting to 30 minutes instead of the default 30 minutes (this prevents attackers from waiting out the lockout). Pro tip: Enable Audit failed logons in Advanced Audit Policy Configuration to get even more granular tracking.

If you're dealing with service accounts that keep failing, check your Group Policy settings for Password never expires—this is a common misconfiguration that leads to locked-out service accounts. For remote systems, verify that Network Security: Restrict NTLM isn't blocking legitimate authentication attempts.

I've seen cases where Kerberos authentication was disabled entirely, forcing systems to fall back to the less secure NTLM—this creates a perfect storm for credential stuffing attacks. Always test changes in a non-production environment first.

For organizations that need more advanced monitoring, consider third-party tools like ManageEngine EventLog Analyzer or Splunk. These solutions can correlate failed logon events with other security alerts, helping you spot patterns like multiple failed attempts from the same IP or unusual logon hours.

I personally use Security Onion for smaller networks—it's free and does real-time correlation of these events with network traffic analysis. The key is balancing native Windows tools with specialized solutions that give you the context missing from raw event logs.

Don't forget to implement Multi-Factor Authentication (MFA) for privileged accounts—this adds an extra layer that stops most automated attacks in their tracks. For local accounts, enable Smart Card or Windows Hello through Credential Manager.

And if you're dealing with legacy systems that can't support MFA, consider Conditional Access Policies in Azure AD to restrict logins to known devices or locations. The goal is to make successful attacks as difficult as possible while keeping legitimate access smooth for your users.