Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

Flooded failed login attempts

Posted on 2016-08-22
8
Medium Priority
?
81 Views
Last Modified: 2016-09-20
Hi Experts,

I'm having an issue with my SBS 2008 server is flooded with failed login attempts like the below example. It doesnt tell me where its coming from or how to stop it - any ideas on how do identify the source and block it.

We currently have  a smoothwall setup as our firewall, which i am trying to get changed for a UTM.

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-a5ba-3e3b0328c30d}" />
    <EventID>4625</EventID>
    <Version>0</Version>
    <Level>0</Level>
    <Task>12544</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8010000000000000</Keywords>
    <TimeCreated SystemTime="2016-08-23T00:45:43.802Z" />
    <EventRecordID>260608564</EventRecordID>
    <Correlation />
    <Execution ProcessID="876" ThreadID="972" />
    <Channel>Security</Channel>
    <Computer>SBS-SERVER.domain.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="SubjectUserSid">S-1-0-0</Data>
    <Data Name="SubjectUserName">-</Data>
    <Data Name="SubjectDomainName">-</Data>
    <Data Name="SubjectLogonId">0x0</Data>
    <Data Name="TargetUserSid">S-1-0-0</Data>
    <Data Name="TargetUserName">ADMINISTRATOR</Data>
    <Data Name="TargetDomainName">
    </Data>
    <Data Name="Status">0xc000006d</Data>
    <Data Name="FailureReason">%%2313</Data>
    <Data Name="SubStatus">0xc000006a</Data>
    <Data Name="LogonType">3</Data>
    <Data Name="LogonProcessName">NtLmSsp </Data>
    <Data Name="AuthenticationPackageName">NTLM</Data>
    <Data Name="WorkstationName">
    </Data>
    <Data Name="TransmittedServices">-</Data>
    <Data Name="LmPackageName">-</Data>
    <Data Name="KeyLength">0</Data>
    <Data Name="ProcessId">0x0</Data>
    <Data Name="ProcessName">-</Data>
    <Data Name="IpAddress">-</Data>
    <Data Name="IpPort">-</Data>
  </EventData>
</Event>
0
Comment
Question by:isdd2000
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
  • 2
  • +1
8 Comments
 
LVL 29

Assisted Solution

by:Dr. Klahn
Dr. Klahn earned 500 total points (awarded by participants)
ID: 41766230
Quick and dirty:  Install Microsoft TCP View on the afflicted system and watch the IP addresses to see which one(s) is flooding the server.

Slower but provably correct:  Install Microsoft Process Monitor, restrict the events to TCP Connects and Login, and run it for a while.  Then read out the log, correlate connects and login attempts, and see which IP address(es) is flooding the server.
0
 

Author Comment

by:isdd2000
ID: 41766281
TCP View is a little difficult to go through everything given its a domain controller the list just keeps updating & i cannot see anything even when paused.

Ill try Microsoft Process Monitor now, i have Trend running a local firewall for Intrusion prevention but it still occurring.
0
 
LVL 36

Expert Comment

by:Kimputer
ID: 41766572
Probably it's internal traffic only (and your firewall probably blocks external traffic).
Probably the fastest way to weed it out, is to ask employees to stop using their computers (and close all open windows and apps) for a while. The traffic will now be more manageable.
It could be malware trying brute force, but could also be something as innocent as a misconfigured printer/storage device that tries to deliver files to the server (but doesn't have the correct credentials input).
0
 [eBook] Windows Nano Server

Download this FREE eBook and learn all you need to get started with Windows Nano Server, including deployment options, remote management
and troubleshooting tips and tricks

 
LVL 30

Assisted Solution

by:pgm554
pgm554 earned 500 total points (awarded by participants)
ID: 41767358
Do you have Remote Web Access set up?
If so ,it's just folks trying to break into your server by using bots.
Unless you take it off the net,there's little you can do.
0
 

Author Comment

by:isdd2000
ID: 41779323
Hi Kimputer,

If its local traffic wouldnt the event log have a local ip that is the cause?

pgm554,

We do have RWW setup and i took IIS offline and the attack still came in.
0
 

Author Comment

by:isdd2000
ID: 41779327
Also they have tried close to 400 different usernames it can not be an internal device misconfigured.
0
 
LVL 36

Accepted Solution

by:
Kimputer earned 1000 total points (awarded by participants)
ID: 41779679
Then it sounds like malware. Install Wireshark on the RDP server. Then start a capture on the NIC with
port 3389
(or which ever port it should be).
Obviously, ask the people to stop working for a bit. If not attack pattern is visible (please note your own IP will show up as a stream if you use RDP to connect to the server), then try again with:
port 80 or port 445 or port 135 or port 137  or port 139
Check for attach patterns again.
If still nothing, then try again without any filter (or if you use RDP, use
not port 3389
)
0
 
LVL 29

Expert Comment

by:Dr. Klahn
ID: 41806176
System requested close
0

Featured Post

Are your AD admin tools letting you down?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A bad practice commonly found during an account life cycle is to set its password to an initial, insecure password. The Password Reset Tool was developed to make the password reset process easier and more secure.
IF you are either unfamiliar with rootkits, or want to know more about them, read on ....
This Micro Tutorial hows how you can integrate  Mac OSX to a Windows Active Directory Domain. Apple has made it easy to allow users to bind their macs to a windows domain with relative ease. The following video show how to bind OSX Mavericks to …
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

618 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question