ALIASES:

Backdoor:Win32/FlyAgent.H (Microsoft); BackDoor-DRV.gen.c (McAfee); ARC:Embedded, [script.fly]:Trojan-Spy.Win32.FlyStudio.dyf, PAK:[krnln.fnr]:UPX (Kaspersky); Backdoor.Win32.FlyAgent.h (v) (Sunbelt); Trojan:W32/Agent.DNQW (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor 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

Tipo de compactação: 741,229 bytes
Tipo de arquivo: EXE
Residente na memória: Yes
Data de recebimento das amostras iniciais: 26 Apr 2012

Arrival Details

This backdoor 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 backdoor creates the following folders:

  • %User Temp%\E_4
  • %User Temp%\BClib

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Autostart Technique

This backdoor 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\HHServerName\Parameters

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\rising\
KaKa

HKEY_CURRENT_USER\Software\FlySky\
E\Install

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\rising\
KaKa
procrun = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Check_Associations = "NO"

HKEY_CURRENT_USER\Software\FlySky\
E\Install
Path = "%User Temp%\BClib"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\HHServerName\Parameters
Application = "%System%\HHClientName.exe"

Dropping Routine

This backdoor drops the following files:

  • %User Temp%\E_4\krnln.fnr
  • %User Temp%\E_4\Exmlrpc.fne
  • %User Temp%\E_4\dp1.fne
  • %System%\HHClientName.exe
  • {malware path and file name}_and deleteme.bat
  • %System%\HHClientName.dll
  • %User Temp%\_eviip.tmp
  • %Windows%\Fonts\dfab2c6259b278c98cbe466e8e73acd2.dat
  • %User Temp%\BClib\krnln.fnr
  • %User Temp%\BClib\dp1.fne
  • %User Temp%\BClib\Exmlrpc.fne
  • %User Temp%\BClib\krnln.fne

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.. %Windows% is the Windows folder, which is usually C:\Windows.)

This report is generated via an automated analysis system.

  SOLUTION

Mecanismo de varredura mínima: 9.200

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\SYSTEM\CurrentControlSet\Services\HHServerName
    • Parameters
  • In HKEY_LOCAL_MACHINE\SOFTWARE\rising
    • KaKa
  • In HKEY_CURRENT_USER\Software\FlySky\E
    • Install

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\rising\KaKa
    • procrun = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Check_Associations = "NO"
  • In HKEY_CURRENT_USER\Software\FlySky\E\Install
    • Path = "%User Temp%\BClib"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\HHServerName\Parameters
    • Application = "%System%\HHClientName.exe"

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.
  • %User Temp%\E_4\krnln.fnr
  • %User Temp%\E_4\Exmlrpc.fne
  • %User Temp%\E_4\dp1.fne
  • %System%\HHClientName.exe
  • {malware path and file name}_and deleteme.bat
  • %System%\HHClientName.dll
  • %User Temp%\_eviip.tmp
  • %Windows%\Fonts\dfab2c6259b278c98cbe466e8e73acd2.dat
  • %User Temp%\BClib\krnln.fnr
  • %User Temp%\BClib\dp1.fne
  • %User Temp%\BClib\Exmlrpc.fne
  • %User Temp%\BClib\krnln.fne

Step 6

Search and delete these folders

[ 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
  • %User Temp%\BClib

Step 7

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