Can somebody explain a brute force attack from a Microsoft IP address?
Websites are easy targets for various network attacks simply because they are available to the public. What protects a website from being “hacked” is a rather thin veneer of passwords, strengthened by a range of firewall measures. WordPress, a popular platform on which websites are based, is particularly vulnerable because its coding embeds user names into a cache that is easily visible to hackers with minimal skills. So the strength of protection must rest on the password. A highly complex password is essential.
WordPress makes these efforts rather futile by only granting so many attempts from a particular source. A failed attempt can trigger a notification to the owner of the website, upon which other defensive measures can be taken such as blocking a specific IP address or a range of IP addresses. This entire process can be automated by subscribing to website security services. This is an ideal solution for most website owners because few have the knowledge or interest to delve into the innards of the Internet. These failed logins are logged, providing important details as to the source, the user name exploited and the technique.
Me? I am still hands-on, combining automated security logging with security techniques. So it was that I was doing a monthly review of the security logs when a rather unusual IP address came up. I recognized it almost right away because of the research work I am doing for The Windows Chronicles. It was a 52 series IP address. These addresses are owned by Microsoft. The address in question was 52.225.23.15.
The 52 series is typically composed of hosting sites that facilitate automated services for the Windows operating system and for Microsoft software products. This includes crash management, One Drive, the Search Host which is engaged when you click the Search box at the bottom of your screen, even Explorer. And even though I do not use the Microsoft Office suite, the winword.exe file (Word) will periodically engage a 52 series host, as does Excel. I am sure there is more out there to discover.
But those are hosting operations. These type of sites only engage requests for engagement. While it may be alarming that so much of the Windows operating system is no longer private (none of this is evident in the Linux environment), these hosting services are legal and, for the most part, useful to both the customer and Microsoft.
A brute force attack stemming from one of these servers? That is a problem.
I have bounced this off several sources including Microsoft and nothing substantive has turned up. So it remains a mystery.
The 52 series is considered a Class A IP network. What this means is that Microsft, which owns the rights to use this network, has available for its use all the IP addresses beneath it, from 52.0.0.0. to 52.255.255.255. If my math is accurate, that is 2553, or 16.6 million addresses. This series can be subnetted, of which 52.225 is one. It can be subnetted further, such as 52.225.23. It is possible that Microsoft has allotted part of the 52 series to workstations for administrative purposes that have the capability to go out into the Internet, to seek and engage. The address in question may be that of an engineer who is curious to see how brute force attacks work. Who knows.
Here are the details. The events occurred in December 2024 over a two day period.
| 12/12/24 05:45 PM | 52.225.23.15 |
| 12/13/24 09:38 AM | 52.225.23.15 |
The good news is that it has not reoccurred since.
So I employed some of my basic tools to see what I could find out.
First, was this a one-off event? AbuseIP says no. This IP address has been reported forty—seven times rating as a 31% risk. Reported activity was for December only. So my situation is not unique, shared by numerous other sites. (Yet, as the image demonstrates, this risk level has dropped to 18%).
Second, I tried to confirm its routing.
Ping was non-responsive. This means the system in question was off-line or not accessible from the outside.
Tracert (trace routing) reported activity all the way back to a 104. series router which is owned by msn.net. So the Microsoft router was engaged on this trace. But that was about as far as it went.
I tried using nmap, a third party network mapping tool, to see if the results would be different. It was not as verbose as tracert, but its ping test reported the address as “active.” Curious how that happened.
Microsoft, to their credit, did respond. But it is evident that despite explicitly directing the inquiry to their security team, it was routed to their customer support team and what I got amounted to nothing more than a marketing message to use Office 365.
So that is why I publish this. Maybe somebody out there has had a similar observation and has obtained more information. It is an interesting riddle.
I seriously doubt that Microsoft, as a corporation, would engage a non-consequential WordPress site with a primitive brute force attack. But without their input, we cannot affirm that conclusion It is possible that this subnet is leased out to a different company. It could have simply been an employee having some fun. But 47 events over a thirty day period? That sounds a bit more sinister. The good news is that it appears that the risk level has dropped from 31% to 18%, implying that Microsoft may have identified this problem and addressed it.
© Copyright 2025 to Eric Niewoehner