Event ID 4625 | �Ӱɴ�ý

What Is Event ID 4625?

Event ID 4625 is a Windows Security log entry that happens whenever a user tries (and fails) to log on to a Windows system. This event can happen for lots of reasons: maybe someone mistyped their password, or an employee left the company and their old credentials are being tested. Or it could be something a lot more malicious—like cybercriminals trying to brute-force their way into your network.

This event is recorded in the Windows Event Viewer under the Security category. Each failed logon attempt logged as Event ID 4625 gives you details like the username, domain, and sometimes the source IP address of the machine that attempted to authenticate.

With these details, your IT or security team can start piecing together the story behind the failure: was it a simple mistake or a sign of something more nefarious?

What Does a Failed Logon Attempt Mean?

On the surface, a failed logon attempt just means that someone tried (and failed) to access a system. We’ve all forgotten a password at some point, so an occasional failed attempt is completely normal. But when Event ID 4625 starts appearing frequently, it’s time to pay more attention.

Repeated failed logon attempts could mean:

Brute force attacks: Cybercriminals might be systematically guessing passwords, hoping that eventually they’ll stumble upon the right one.
Credential stuffing: Attackers use stolen usernames and passwords from past breaches, testing them on your environment in the hope that someone reused their old (compromised) credentials.
Internal threats: Disgruntled employees or unauthorized staff might try to access sensitive information.
Configuration mistakes: Sometimes it’s not an external attacker at all. Misconfigurations or software bugs can cause recurring failed attempts, flooding your logs with false alarms. While this is technically a good thing (or a not bad thing), it’s still an issue that needs to be checked out.

Why Can Event ID 4625 Be a Cyber Threat?

Failed logon events are more than just annoying noise in your logs—they can mean a threat actor is trying to get into your environment.

Here’s what you need to know about:

Early warning signs of intrusions: Attackers often start low and slow, testing a few passwords here and there. Over time, they may ramp up the intensity of their attempts. Spotting these early failures gives you a chance to tighten your defenses before a breach happens.
Credential-based attacks: Credentials will always remain a top target for cybercriminals. If credentials can be cracked or guessed, the attacker now has the same level of access as the rightful user—sometimes even administrative privileges, which is obviously not ideal.
Insider threats: As you know, not all threats come from the outside. Consistent failed attempts within your internal network could point to an employee with malicious intent or a compromised internal account trying to gain access and privileges.

How to Interpret Event ID 4625

If you see an Event ID 4625 entry, don’t panic. But consider these factors:

Frequency: Is this a one-time event or part of a recurring pattern?
User context: Which accounts are failing? Are they high-level accounts or standard user accounts?
Location and source: Check where the attempts are coming from. Are they tied to an unknown IP address or a device outside your normal environment?
Timing: Did these attempts happen at odd hours when legitimate users wouldn’t usually be logging in?

These questions can help explain whether you’re dealing with a real threat or user error.

Reducing Risk

Good (cyber) hygiene goes a long way. You can reduce the risk associated with failed logon attempts by implementing the following best practices:

Enforce strong password policies: This one’s easy. To make brute-force attacks more difficult, require complex passwords and mandate multi-factor authentication (MFA).
Limit login attempts: Set account lockout policies to temporarily disable accounts after a certain number of failed attempts.
Log and monitor activity: Use a Security Information and Event Management (SIEM) solution to centralize your logs and automate alerting on suspicious patterns. This enhanced visibility helps you respond faster to potential threats.
User education: Train your employees on password hygiene and the importance of reporting suspicious login attempts with Security Awareness Training (SAT).

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