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WORM_AGENT.AEWN

October 12, 2012
 ALIASES:

Worm:Win32/Nuj.A (Microsoft); BackDoor-DPR (McAfee); Backdoor.Trojan (Symantec); ARC:Embedded, [script.fly]:Trojan-Dropper.Win32.Flystud.ah, PAK:[krnln.fnr]:UPX, PAK:[dp1.fne]:UPX, (Kaspersky); Trojan.Win32.Autorun.dm (v) (Sunbelt); Trojan-Downloader:W32/VB.BUE (FSecure)

 PLATFORM:

Windows 2000, Windows, XP, Windows Server 2003

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

  TECHNICAL DETAILS

File Size:

757,273 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

23 Nov 2011

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system:

  • %System%\Ó¦ÓóÌÐò.exe

(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.)

It creates the following folders:

  • %User Temp%\E_4

(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.)

Autostart Technique

This worm registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Ó¦ÓóÌÐò\Parameters

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Ó¦ÓóÌÐò\Parameters
Application = "%System%\Ó¦ÓóÌÐò.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Ó¦ÓóÌÐò
Description = "ÄÖ¾çCF¸ÄǹÃëɱ¸¨Öú"

Dropping Routine

This worm drops the following files:

  • %User Temp%\E_4\krnln.fnr
  • %User Temp%\E_4\dp1.fne
  • %User Temp%\E_4\Exmlrpc.fne
  • %System Root%\delus.bat
  • %System%\Ó¦ÓóÌÐò.dll
  • %Windows%\IJL105.DLL
  • %Windows%\Fonts\Ó¦ÓóÌÐò.jpg
  • %Windows%\dp1.fne
  • %Windows%\Exmlrpc.fne
  • %Windows%\krnln.fnr

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

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

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\SYSTEM\CurrentControlSet\Services\Ó¦ÓóÌÐò
    • Parameters

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\SYSTEM\ControlSet001\Services\Ó¦ÓóÌÐò\Parameters
    • Application="%System%\Ó¦ÓóÌÐò.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Ó¦ÓóÌÐò
    • Description="ÄÖ¾çCF¸ÄǹÃëɱ¸¨Öú"

Step 5

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%\E_4

Step 6

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.
  • %User Temp%\E_4\krnln.fnr
  • %User Temp%\E_4\dp1.fne
  • %User Temp%\E_4\Exmlrpc.fne
  • %System Root%\delus.bat
  • %System%\Ó¦ÓóÌÐò.dll
  • %Windows%\IJL105.DLL
  • %Windows%\Fonts\Ó¦ÓóÌÐò.jpg
  • %Windows%\dp1.fne
  • %Windows%\Exmlrpc.fne
  • %Windows%\krnln.fnr

Step 7

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_AGENT.AEWN. 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.


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