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Trojan:Win32/Buzus.C


Trojan:Win32/Buzus.C is a malicious program that is unable to spread of its own accord. It may perform a number of actions of an attacker's choice on an affected machine.


What to do now

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as Microsoft Security Essentials, or the Microsoft Safety Scanner. For more information about using antivirus software, see http://www.microsoft.com/security/antivirus/av.aspx.

Threat behavior

Trojan:Win32/Buzus.C is a malicious program that is unable to spread of its own accord. It may perform a number of actions of an attacker's choice on an affected machine.
Installation
When executed, Trojan:Win32/Buzus.C copies itself to c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\msmxeng.exe.

The malware modifies the following registry entry/ies to ensure that its copy executes at each Windows start:
Adds value: "Taskman"
With data: "c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\msmxeng.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

The malware creates the following file(s) on an affected machine:
  • c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\desktop.ini

The malware utilizes code injection in order to hinder detection and removal. When Trojan:Win32/Buzus.C executes, it may inject code into running processes, including the following, for example:
explorer.exe

This malware description was produced and published using our automated analysis system's examination of file SHA1 94731056a29249a80b880335319fd2185cac4139. If you would like to comment on this analysis, please send your feedback to mmpc-amd@microsoft.com.

Symptoms

System changes
The following system changes may indicate the presence of this malware:
Presence of the following file/s:
c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\desktop.ini
c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\msmxeng.exe

The presence of the following registry modifications :
Adds value: "Taskman"
With data: "c:\recycler\s-1-5-21-4867718599-0216009167-377740393-2438\msmxeng.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

Prevention


Alert level: Severe
First detected by definition: 1.69.393.0
Latest detected by definition: 1.69.393.0 and higher
First detected on: Oct 31, 2009
This entry was first published on: May 28, 2010
This entry was updated on: Apr 17, 2011

This threat is also detected as:
  • TROJ_BUZUS.BFK (Trend Micro)
  • Trojan.Win32.Buzus.cbge (Kaspersky)
  • Trojan Horse (Symantec)