Event ID 4625: What It Means and What to Do When You See Thousands
If you've ever opened the Windows Event Viewer and searched through security events, you've probably come across this number: 4625. And you probably didn't see just one or two – you saw hundreds. Or thousands.
This number shows up so frequently for a reason. Let's look at what it means, why it matters, and what you can do about it.
What is Event ID 4625?
Put simply: someone tried to log in to your machine and failed. They entered a wrong password, tried a non-existent username, or attempted a login method the system doesn't allow.
Windows records every such event in the Security Log, and each entry gets the same identifier: 4625.
One or two of these entries is perfectly normal – everyone mistypes a password occasionally. The problem starts when you see hundreds or thousands per day.
How to check if you're affected
Press Windows + R, type eventvwr.msc, and hit Enter. In the left tree, click Windows Logs → Security. On the right side, select Filter Current Log, and in the Event ID field, type: 4625.
What appears is the list of failed login attempts. If your server is accessible via Remote Desktop from the internet, you almost certainly won't see an empty list.
What does a 4625 entry tell you?
Each entry contains:
- Who tried – the username (Account Name). If you see names like "Administrator", "Admin", "Test", "User" – it's almost certainly an external attempt.
- Where it came from – the attacker's IP address (Source Network Address). Foreign, unknown IPs are a sign of automated attacks.
- When it happened – exact date and time. If hundreds of attempts come at 3 AM, it wasn't your colleague.
- Why it failed – the error reason (Status/Sub Status code). Most common: wrong password (0xC000006A) or non-existent user (0xC0000064).
Why so many?
The short answer: automated programs (bots) scan the internet and try every reachable Windows server. They're not targeting you personally – they simply try everyone with Remote Desktop open (RDP, default port 3389).
These bots don't tire out. They work around the clock, using dictionaries and leaked password lists. 5,000 to 10,000 attempts per day against a single server is not unusual.
Why does it matter if they can't get in?
Three reasons:
1. Your server is doing the work. Every 4625 event means the system received the request, evaluated it, rejected it, and logged it. Ten thousand of these per day is unnecessary load on CPU and memory.
2. The log fills up with noise. When thousands of junk entries pile up, it becomes much harder to spot when something genuinely important happens. A real security incident can easily get lost in the noise.
3. The risk grows over time. One month means a hundred and fifty thousand attempts, one year means almost two million. If the attacker is working with leaked password lists, they're not shooting completely blind – and time is on their side.
What can you do?
The goal is simple: if someone enters the wrong password multiple times, they shouldn't be able to try again. Block their IP address – automatically, immediately.
BruteFence does exactly this: it monitors Event ID 4625 entries, and when a set number of failed attempts come from the same IP, it creates a Windows Firewall rule to block the attacker. After that, the attacker can't even reach the server.
Installation takes 5 minutes, and the program quietly runs in the background – no maintenance needed.
Check your own server
If you're curious how many 4625 events are on your server but don't want to dig through the Event Viewer manually, download the free BruteFence Checker. With a single click, it shows all failed login attempts from the past 30 days – with IP addresses, usernames, and dates.
Summary
Event ID 4625 means a failed login attempt. If you see hundreds or thousands daily, your server is an active target. This doesn't stop on its own – but BruteFence handles it automatically: it blocks the intruders, reduces the load, and keeps your logs clean.
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