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zylorian

An (New?) Radmin Brute-Force Zombie, And How To Remove It

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Hello all,

 

I would like to report malware that neither AVG's Complete Scan nor avast!'s Scan on Boot detected.

 

Summary


The machine runs code that connects to other machines using RAdmin. It then runs as a zombie to brute-force access to other machines. It then sends the failed/successful username/password lists to a server.

 

Symptoms


Computer runs slow

Outgoing connection found on port 4899, like the following:

Scanning summary: Date Protocol Port or Type/Code Dst count

2012-03-28 17:00:00 6 (TCP) 4899 (radmin-port) 142

2012-03-28 17:05:00 6 (TCP) 4899 (radmin-port) 146

2012-03-28 17:10:00 6 (TCP) 4899 (radmin-port) 148

2012-03-28 17:15:00 6 (TCP) 4899 (radmin-port) 143

 

Removal Instructions


1) Determine the process that has outbound connections on Port 4899 using [TCPView] (for me it was msgsm.exe which was the fake name used for the program lamescan3.exe).

2) Find the location of the .exe file (for me it was C:\WINDOWS\system32\dllcache\).

3) Stop the process using Task Manager or other equivalent.

4) This malware also uses a service to start this executable on startup. Find the name of the service.

--1) Find the batch file that starts the service (mine was mshts.bat). Although tedious, one way to determine which file in this folder is the following:

----1) Find all files ending in .bat.

----2) Open each one in a text editor and search for curl or wget, programs used to upload and download information from the server.

--2) Search the batch file for a command like sc stop MsHosts, where MsHosts is the name of the malware service.

--3) Search the registry for the DisplayName of the service. Go to Start -> Run and type regedit. Then hit Ctrl-F and type the name of the malware service. In that folder will be a registry key called DisplayName. We'll use that value to find the service and disable it. For me, the DisplayName was Manager mapping IP addresses to hosts and the Description was written in quite poor English...

5) Go to Start -> Control Panels -> Administrative Tools -> Services and look for the DisplayName that you found in the registry. Right-click it, go to Properties, click Stop and change the Startup Type to Disabled.

6) In the registry (which you can open by clicking Start -> Run and type regedit), right-click on the malware service folder, note the name of the Path to executable (for me it was (C:\WINDOWS\system32\dllcache\mgm.exe), select Delete and select Yes.

7) Delete both executables (e.g. msgsm.exe and mgm.exe). Then search in the batch file for any associated files (e.g. ___.dll or ___.ger) and delete those as well. Finally, delete the batch file.

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Hello zylor, It is amazing the new threats and variants of known threats that emerge everyday! Those zombie viruses are relatively new to the scene and as you found out sometimes very hard to defeat because of the fact they infect your Master Boot Sector (startup program) and can propagate to other parts of your OS as well. I think most people would have given up and just reformatted their OS. Your perseverance certainly payed off! I can also tell your no novice when it comes to battling malware infections. I think your info will certainly benefit some one else that's unlucky enough to become infected with this malware and reads your forum topic! Thanks for the informative post zylor! Best wishes, Ritchie...

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