Virus:TR/Dldr.Agent.amzp
Date discovered:31/10/2008
Type:Trojan
Subtype:Downloader
In the wild:Yes
Reported Infections:Low to medium
Distribution Potential:Low
Damage Potential:Medium
Static file:Yes
File size:77.828 Bytes
MD5 checksum:20edfd7563e866c1c149fca2b03ec634
IVDF version:7.01.00.23 - Friday, October 31, 2008

 General Method of propagation:
   • No own spreading routine


Aliases:
   •  Symantec: Trojan.Fakeavalert.B
   •  Mcafee: Downloader-BKM trojan
   •  Kaspersky: Trojan-Downloader.Win32.Agent.amzp
   •  F-Secure: Trojan-Downloader.Win32.Agent.amzp
   •  Eset: Win32/TrojanDownloader.FakeAlert.OY trojan


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


Side effects:
   • Downloads malicious files
   • Registry modification

 Files It tries to download some files:

– The location is the following:
   • http://193.142.244.55/**********/item_g.gif
It is saved on the local hard drive under: %TEMPDIR%\~tmpa.exe Furthermore this file gets executed after it was fully downloaded. Further investigation pointed out that this file is malware, too. Detected as: TR/BHO.hfq


– The location is the following:
   • http://193.142.244.20/**********/216-1.exe
It is saved on the local hard drive under: %TEMPDIR%\~tmpc.exe Furthermore this file gets executed after it was fully downloaded. Further investigation pointed out that this file is malware, too. Detected as: TR/Crypt.ULPM.Gen


– The location is the following:
   • http://bigimagecatalogue.com/**********/chagall.gif
It is saved on the local hard drive under: %TEMPDIR%\~tmpd.exe Furthermore this file gets executed after it was fully downloaded. Further investigation pointed out that this file is malware, too. Detected as: TR/Agent.87552.F

 Registry One of the following values is added in order to run the process after reboot:

–  [HKCU\Software\Microsoft\Windows\CurrentVersion\Run]
   • "MSFox"="%executed file%"



The following registry keys are added:

– [HKLM\SOFTWARE\Mozilla\MSFox]
   • "Str5"="%random character string%"
   • "Str9"="%random character string%"
   • "Str6"="%random character string%"
   • "Str7"="%random character string%"
   • "Str8"="%random character string%"
   • "Str4"="%random character string%"
   • "Str1"="%random character string%"
   • "Int2"=dword:%hex number%
   • "Int3"=dword:%hex number%

– [HKLM\Software\Microsoft\RFC1156Agent\CurrentVersion\Parameters]
   • "TrapPollTimeMilliSecs"=dword:%hex number%

 File details Programming language:
 The malware program was written in MS Visual C++.


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

Description inserted by Andreas Feuerstein on Friday, November 14, 2008
Description updated by Andreas Feuerstein on Friday, November 14, 2008

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