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The Internet threat alert status is currently normal. At present, no major epidemics or other serious incidents have been recorded by Kaspersky Lab’s monitoring service. Internet threat level: 1

Trojan-Downloader.Win32.Small.bven

Detected Apr 07 2011 18:37 GMT
Released Apr 12 2011 07:45 GMT
Published Sep 09 2011 15:39 GMT

Technical Details
Payload
Removal instructions

Technical Details

A trojan program that downloads files from the internet without the user's knowledge and launches them. It is a Windows application (PE-EXE file). 7168 bytes. Written in C++.

Installation

When launching, the trojan copies its executable file under the following name:

%WinDir%\System\svchost.exe
So that it may be automatically launched each time the system is started, the trojan adds a link to its executable file in the system registry startup key:
[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
"svchost.exe"="%WinDir%\System\svchost.exe"


Payload

When launching, the trojan looks for and carries out the following processes within the system:

NaverAgent.exe
Nsavsvc.npc
nsvmon.npc
NVCAgent.npc
Vcrmon.exe
SpiderNt.exe
SpiderUI.exe
AYAgent.aye
AYServiceNT.exe
The trojan then downloads 4 files from the following links:
http://www.j***utl.info/gx2/x4.txt
http://www.i***ef.info/gx/x3.txt
http://www.g***fj.info/xztj/22.txt
http://www.o***rh.info/xztj1/12.txt
These links did not work when creating the description.

The downloaded files are saved in the current user's temporary file directory under the following names:

%Temp%\<rnd>.exe
Where <rnd> – random digits.

The downloaded files are then launched and the trojan shuts down. The trojan is deleted when reloading the original file.


Removal instructions

If your computer has not been protected with anti-virus software and has been infected with malware, you will need to take the following actions to delete this:

  1. Delete the original program file (its location on the infected computer will depend on how the program got onto the computer).
  2. Delete the files downloaded by the trojan located in the current user's temporary file directory under the following names.
  3. Delete the system registry key (how to work with the registry?):
    [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
    "svchost.exe"
    
  4. Run a full Kaspersky Antivirus scan of the computer with updated antivirus databases (download trial version).


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Trojan-Downloader

Programs classified as Trojan-Downloader download and install new versions of malicious programs, including Trojans and AdWare, on victim computers. Once downloaded from the Internet, the programs are launched or included on a list of programs which will run automatically when the operating system boots up.

Information about the names and locations of the programs which are downloaded are in the Trojan code, or are downloaded by the Trojan from an Internet resource (usually a web page).

This type of malicious program is frequently used in the initial infection of visitors to websites which contain exploits.


Other versions

Aliases

Trojan-Downloader.Win32.Small.bven (Kaspersky Lab) is also known as:

  • Heuristic.WinPE-Statistical (Panda)
  • Trojan.Generic.KD.178848 (BitDef7)
  • Trojan.DL.Small!4wG7+ZMeLLg (VirusBuster)
  • Win32:Malware-gen (AVAST)
  • Trojan.Win32.Swisyn (Ikarus)
  • Trojan.Gen (NAV)
  • NseCheckFile2() returned 0x00010018 (Norman)
  • [Suspicious] (Rising)
  • Trojan.DL.Small!4wG7+ZMeLLg (VirusBusterBeta)