Event ID 4648 signifies that a logon was attempted using explicit credentials on a Windows system. This critical security event is recorded in the Windows security event log when a process explicitly specifies the credentials (like a username and password) of an account to attempt a logon, rather than relying on inherited or cached credentials.
This event is particularly important for auditing and security monitoring, as it captures instances where an application, script, or service directly provides authentication details for a specific user account.
Understanding Explicit Credentials
Unlike a standard interactive logon (where a user logs into a desktop) or network logon (where a user accesses a shared resource using their current session's credentials), an explicit credential logon means:
- Direct Specification: A program, script, or service supplies a username and password directly as part of its operation.
- Impersonation or Delegation: Often used when a process needs to run a task or access resources on behalf of a different user account than the one currently logged on or under which the process itself is running.
When is Event ID 4648 Generated?
Event ID 4648 is commonly generated in scenarios involving automated processes and service accounts:
- Batch-Type Configurations: This is a primary scenario where scripts or scheduled tasks need to perform actions using specific accounts without a user interactively logging in. For example, a script running a backup operation might use explicit credentials to access a network share under a dedicated backup service account.
- Service Accounts: Applications or services that need to connect to other systems (like databases, web servers, or file shares) with specific permissions might use explicit credentials if configured to do so.
runasCommand: When a user explicitly uses therunascommand to execute an application or command under different user credentials.- PowerShell Scripts: PowerShell scripts that use
Invoke-Commandor other cmdlets requiring alternate credentials often trigger this event.
Key Details of Event ID 4648
For clarity, here's a summary of Event ID 4648:
| Event ID | Category | Description | Common Scenarios |
|---|---|---|---|
| 4648 | Logon/Logoff (Audit Logon) | A logon was attempted using explicit credentials. | Scheduled tasks, runas command, automated scripts, service-to-service communication. |
Security Implications and Monitoring
Monitoring Event ID 4648 is crucial for maintaining a robust security posture:
- Detecting Credential Misuse: While often legitimate, a sudden surge of Event ID 4648 from unusual sources or for sensitive accounts can indicate an attacker attempting to use stolen credentials (e.g., a "pass-the-hash" or "pass-the-ticket" attack) for lateral movement within a network.
- Understanding Application Behavior: It helps administrators understand which applications or scripts are using specific credentials, aiding in troubleshooting and permission management.
- Compliance and Auditing: Provides a forensic trail for compliance requirements, showing when specific accounts were used, even without a full interactive logon.
What to Look For When Analyzing 4648 Events:
- Source Process Name: Identify the executable or script that initiated the logon attempt.
- Target Account Name: The name of the account for which the explicit logon was attempted.
- Logon Process: Details about the process attempting the logon (e.g.,
User32,Advapi). - Network Information: If the attempt originated over the network, details like the source IP address can be critical.
For more detailed information on Windows security events and their auditing, you can refer to official Microsoft documentation on Windows security auditing.
