TROJ_DLOADER.DFH

October 24, 2013
 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:

712,400 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

02 Oct 2013

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.

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SitecheckPopUP = "%Windows%\sitecheckpopup.exe"

Other System Modifications

This Trojan deletes the following files:

  • %System Root%\$$DELS~1.BAT

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

It adds the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
WAS.Event.Help\CLSID

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
ButtonText = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
MenuText = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
ToolTip = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
MenuStatusBar = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
CLSID = "{1FBA04EE-3024-11d2-8F1F-0000F87ABD16}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
Default Visible = "Yes"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
Exec = "http://www.{BLOCKED}eck.co.kr/partner.asp?pid=toolbtn&bidx=51"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
HotIcon = "%Windows%\sitecheck.ico"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
Icon = "%Windows%\sitecheck.ico"

It deletes the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\
Internet Explorer\Extensions\{10954C80-4F0F-11d3-B17C-00C0DFE39736}

Dropping Routine

This Trojan drops the following files:

  • %Windows%\sitecheckpopup.exe
  • %Windows%\sitecheck.ico
  • %Desktop%\ÁֹιøÈ£ µµ¿ëÈ®ÀÎ.url
  • %Favorites%\³»°¡ °¡ÀÔÇÑ »çÀÌÆ® È®ÀÎ.url
  • %System Root%\$$DelSelf.bat

(Note: %Windows% is the Windows folder, which is usually C:\Windows.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.. %Favorites% is the current user's Favorites folder, which is usually C:\Documents and Settings\{user name}\Favorites on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Favorites on Windows Vista and 7.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

Other Details

This Trojan deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.300

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Delete this registry key

[ 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\Internet Explorer\Extensions
    • {1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WAS.Event.Help
    • CLSID

Step 4

Delete this 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\Windows\CurrentVersion\Run
    • SitecheckPopUP = "%Windows%\sitecheckpopup.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • ButtonText = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • MenuText = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • ToolTip = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • MenuStatusBar = "»çÀÌƮüĿ(¸íÀǵµ¿ëÈ®ÀÎ)"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • CLSID = "{1FBA04EE-3024-11d2-8F1F-0000F87ABD16}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • Default Visible = "Yes"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • Exec = "http://www.{BLOCKED}eck.co.kr/partner.asp?pid=toolbtn&bidx=51"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • HotIcon = "%Windows%\sitecheck.ico"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Extensions\{1A92F9C0-BC59-44B8-B429-CF2E4A67D423}
    • Icon = "%Windows%\sitecheck.ico"

Step 5

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %Windows%\sitecheckpopup.exe
  • %Windows%\sitecheck.ico
  • %Desktop%\ÁֹιøÈ£ µµ¿ëÈ®ÀÎ.url
  • %Favorites%\³»°¡ °¡ÀÔÇÑ »çÀÌÆ® È®ÀÎ.url
  • %System Root%\DelSelf.bat
DelSelf.bat
  • In the Look In drop-down list, select My Computer then press Enter.
  • Once located, select the file then press SHIFT+DELETE to delete it.
  • Repeat the said steps for all files listed.

    • • For Windows Vista and Windows 7 users:

    1. Click Start>Computer.
    2. In the Search input box, type:
      • %Windows%\sitecheckpopup.exe
      • %Windows%\sitecheck.ico
      • %Desktop%\ÁֹιøÈ£ µµ¿ëÈ®ÀÎ.url
      • %Favorites%\³»°¡ °¡ÀÔÇÑ »çÀÌÆ® È®ÀÎ.url
      • %System Root%\DelSelf.bat
    3. Once located, select the file then press SHIFT+DELETE to delete it.
    4. Repeat the said steps for all files listed.
      *Note: Read the following Microsoft page if these steps do not work on Windows 7.

    Step 6

    Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_DLOADER.DFH. 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 7

    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%\DELS~1.BAT

    Step 8

    Restore these deleted registry keys/values from backup

    *Note: Only Microsoft-related keys/values will be restored. If the malware/grayware also deleted registry keys/values related to programs that are not from Microsoft, please reinstall those programs on your computer.

    • In HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Extensions
      • {10954C80-4F0F-11d3-B17C-00C0DFE39736}


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