7,023 questions
step 1 is to block this IP on you network device like firewall , or something .
Unblock it only when you verify who was the owner of device and IP source is trusted.
AD brute force attack
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Özgür Gül
1
Reputation point
Hi guys,
Today when i was inspecting security event logs at active directory server i realised we are recieving constant password brute force attacks from different user accounts.
Usernames were seeming to be coming from a rainbow table as; Jessie, Jaxon, Clare...so on
Source workstation is also seeming to be different on each try as; Windows7, Remmina, Windows2019, Windows10, FreeRDP... (these hosts does not seem to appear on network when i do nslookup control)
The question is i have no identifier to reach an ip address to reach the attacker device.
I am adding an example log output and info i got, and i need guidance to reach further information on which device is sending this requests.
Authentication Package: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0
Logon Account: Matthew
Source Workstation: FreeRDP
Error Code: 0xC0000064
Windows for business | Windows Client for IT Pros | Directory services | Active Directory
Windows for business | Windows Server | Devices and deployment | Configure application groups
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(89.60000000000001, 81%, 18%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ERA%3C/text%3E%3C/svg%3E)
Reza-Ameri 17,341 Reputation points Volunteer Moderator2022-06-28T15:41:47.587+00:00 Is your server connected to internet?
They are from outside your network, is that correct? -
Özgür Gül 1 Reputation point
2022-06-29T06:46:19.317+00:00 No clues if they are insider or outside originated. Thats what i want to find out.
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![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(176, 24%, 27%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EMA%3C/text%3E%3C/svg%3E)
Mohammed Altamash Mohammed Suleman Khan 2,331 Reputation points2022-06-28T15:58:22.16+00:00 -
Özgür Gül 1 Reputation point
2022-06-29T06:47:04.713+00:00 Block this ip, which ip, i only have user and hostname information at logs, user information is random generated and also hostname is random generated.
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Özgür Gül 1 Reputation point
2022-06-29T06:48:18.837+00:00 I can packet capture on Active directory server and try to match packets with event logs checking time of actions i know, but is there a way to find ip from elsewhere?
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Özgür Gül 1 Reputation point
2022-06-29T14:39:02.647+00:00 Finally removing all 3th party apps from client device stopped the AD traffic. Didnt have time to deep analyse the issue so no suspects were found.
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