TR/Dldr.Small.agq.4 - Trojan

See also

Summary

Full description

Statistics

Virus:	TR/Dldr.Small.agq.4
Date discovered:	26/09/2005
Type:	Trojan
Subtype:	Downloader
In the wild:	Yes
Reported Infections:	Low
Distribution Potential:	Low
Damage Potential:	Low to medium
Static file:	Yes
File size:	4.477 Bytes
MD5 checksum:	f858bcfec28369d83492a5d406ecf60c
VDF version:	6.31.1.64

General Method of propagation:
   • No own spreading routine

Aliases:
   • Mcafee: BackDoor-AZV
   • Kaspersky: Trojan-Downloader.Win32.Small.bov
   • Sophos: Troj/Vixup-Gen
   • Bitdefender: Trojan.Downloader.Small.AMA

Platforms / OS:
   • Windows 95
   • Windows 98
   • Windows 98 SE
   • Windows NT
   • Windows ME
   • Windows 2000
   • Windows XP
   • Windows 2003

Side effects:
   • Downloads malicious files

Files It copies itself to the following location:
   • %SYSDIR%\kernels32.exe

The following file is created:

– Non malicious file:
   • %SYSDIR%\vx.tll

It tries to download some files:

– The location is the following:
   • http://**********/adverts/progs/search.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq1.exe Furthermore this file gets executed after it was fully downloaded. Further investigation pointed out that this file is malware, too. Detected as: 547

– The location is the following:
   • http://**********/adverts/progs/winlogon.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq2.exe

– The location is the following:
   • http://**********/adverts/progs/tibs.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq5.exe

– The location is the following:
   • http://**********/adverts/progs/tool.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq6.exe

– The location is the following:
   • http://**********/adverts/progs/proxy.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq7.exe

– The location is the following:
   • http://**********/adverts/progs/search.exe
It is saved on the local hard drive under: %SYSDIR%\vxh8jkdq8.exe

Registry The following registry key is added in order to run the process after reboot:

– [HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
   • "System" = "%SYSDIR%\kernels32.exe"

The following registry key is added:

– [HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System]
   • "DisableTaskMgr"=dword:00000001

The following registry key is changed:

– [HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon]
   Old value:
   • "Shell" = "Explorer.exe"
   New value:
   • "Shell" = "Explorer.exe %SYSDIR%\kernels32.exe"

Backdoor Contact server:
All of the following:
   • http://**********/adverts/039/adload.php
   • http://**********/adverts/039/aduniq.php?vx1=%random character string%

As a result it may send some information. This is done via the HTTP GET request on a PHP script.

Sends information about:
    • Current malware status

File details Runtime packer:
In order to aggravate detection and reduce size of the file it is packed with the following runtime packer:
• FSG 2.0

See a brief description here.

Description inserted by Alexandru Tudor on Tue, 27 Sep 2005 09:34 (GMT+1)
Description updated by Alexandru Tudor on Fri, 30 Sep 2005 11:33 (GMT+1)

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