TROJ_DROPER.SMJN


 ALIASES:

TrojanDropper:Win32/Hupigon.gen!A (Microsoft); [00236a68.EXE]:BackDoor-ALC, [00004a68.EXE]:generic!bg.hhm (McAfee); PAK:PE_Patch, Trojan-Dropper.Win32.Agent.lr (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Dropper.Delf.LR (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

2,628,096 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

18 Apr 2012

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This Trojan creates the following folders:

  • %User Temp%\dat

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

Other System Modifications

This Trojan deletes the following files:

  • %System Root%\clear.bat

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.imaadpcm
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.imaadpcm
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.imaadpcm
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.imaadpcm
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msadpcm
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msadpcm
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msadpcm
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msadpcm
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg711
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg711
cFormatTags = "3"

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg711
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg711
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msgsm610
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msgsm610
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msgsm610
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msgsm610
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.trspch
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.trspch
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.trspch
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.trspch
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg723
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg723
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg723
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msg723
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msaudio1
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msaudio1
cFormatTags = "3"

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msaudio1
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.msaudio1
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.sl_anet
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.sl_anet
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.sl_anet
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.sl_anet
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.iac2
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.iac2
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.iac2
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.iac2
cFilterTags = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.l3acm
fdwSupport = "1"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.l3acm
cFormatTags = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.l3acm
aFormatTagCache = "{random values}"

(Note: The default value data of the said registry entry is {random values}.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
AudioCompressionManager\DriverCache\msacm.l3acm
cFilterTags = "0"

Dropping Routine

This Trojan drops the following files:

  • %System%\flash.dat
  • %System%\mmm.dat
  • %System%\runf.bat
  • clear.bat
  • %User Temp%\EXE_temp0.exe
  • %User Temp%\EXE_temp1.exe
  • %Windows%\TXPlatform.exe
  • {malware path and file name}

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.imaadpcm
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.imaadpcm
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.imaadpcm
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.imaadpcm
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msadpcm
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msadpcm
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msadpcm
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msadpcm
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg711
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg711
    • From: cFormatTags = "3"
      To: cFormatTags = ""3""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg711
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg711
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msgsm610
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msgsm610
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msgsm610
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msgsm610
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.trspch
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.trspch
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.trspch
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.trspch
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg723
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg723
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg723
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msg723
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msaudio1
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msaudio1
    • From: cFormatTags = "3"
      To: cFormatTags = ""3""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msaudio1
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.msaudio1
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.sl_anet
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.sl_anet
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.sl_anet
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.sl_anet
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.iac2
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.iac2
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.iac2
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.iac2
    • cFilterTags = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.l3acm
    • From: fdwSupport = "1"
      To: fdwSupport = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.l3acm
    • From: cFormatTags = "2"
      To: cFormatTags = ""2""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.l3acm
    • From: aFormatTagCache = "{random values}"
      To: aFormatTagCache = ""{random values}""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\AudioCompressionManager\DriverCache\msacm.l3acm
    • cFilterTags = "0"

Step 3

Search and delete these files

[ Learn More ]
There may be some component files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result.
  • %System%\flash.dat
  • %System%\mmm.dat
  • %System%\runf.bat
  • clear.bat
  • %User Temp%\EXE_temp0.exe
  • %User Temp%\EXE_temp1.exe
  • %Windows%\TXPlatform.exe
  • {malware path and file name}

Step 4

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %User Temp%\dat

Step 5

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPER.SMJN. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %System Root%\clear.bat


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