Windows Event ID 4625 (Failed Logon): Causes, Analysis, and Email Notifications
Windows Event ID 4625 is one of the most important security events in Windows. It is generated whenever a logon attempt fails. Administrators commonly use this event to detect:
- Brute-force attacks
- Password spraying attempts
- Outdated service account credentials
- Misconfigured applications
- Active Directory authentication issues
Event ID 4625 is recorded in the Security Log of the affected computer or server.
When Does Event ID 4625 Occur?
Common causes include:
- Incorrect password
- Locked user account
- Disabled user account
- Expired password
- Failed Remote Desktop (RDP) login
- Service running with outdated credentials
Especially on publicly accessible servers, hundreds or even thousands of Event ID 4625 entries can occur every day.
Important Fields in Event ID 4625
When analyzing Event ID 4625, pay special attention to the following fields:
- TargetUserName
- WorkstationName
- LogonType
- Status
- SubStatus
- IpAddress
The Status and SubStatus fields are particularly valuable because they provide detailed information about the reason for the failed logon.
Examples:
- 0xC000006A → Incorrect password
- 0xC0000064 → User account does not exist
- 0xC0000234 → Account locked out
- 0xC0000072 → Account disabled
Why Immediate Notification Is Important
Many administrators only review the Windows Event Log after users have already reported problems.
However, repeated Event ID 4625 entries can be early warning signs of:
- Attack attempts
- Compromised credentials
- Misconfigured services
- Internal configuration errors
Automatic notifications significantly reduce response times and help administrators react before minor issues become major incidents.
Monitor Event ID 4625 with EventMailNotification
With EventMailNotification, you can monitor Windows Event ID 4625 in real time.
As soon as a matching event appears in the Windows Security Log, EventMailNotification automatically sends an email containing the relevant event details.
Benefits:
- Real-time email alerts
- No SIEM solution required
- Easy configuration
- Ideal for Windows Server and Active Directory environments
- Faster troubleshooting and incident response
