TROJ_FLYSTUDI.BA
Backdoor:Win32/FlyAgent.E (Microsoft); BackDoor-DRV.gen.c (McAfee); Backdoor.Trojan (Symantec); Trojan-Spy.Win32.FlyStudio.ael (Kaspersky); Trojan.Win32.Autorun.dm (v) (Sunbelt); Trojan:W32/Agent.DQOD (FSecure)
Windows 2000, Windows XP, Windows Server 2003
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
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%\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.)
Autostart Technique
This Trojan 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\Honhserver\Parameters
Other System Modifications
This Trojan deletes the following files:
- %System Root%\DEL_FI~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\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\Honhserver\Parameters
Application = "%System%\Honhcservice.exe"
Dropping Routine
This Trojan drops the following files:
- %User Temp%\BClib\krnln.fnr
- %User Temp%\BClib\Exmlrpc.fne
- %User Temp%\BClib\dp1.fne
- %System%\Honhcservice.exe
- %System Root%\del_filme.bat
- %System%\Honhcservice.dll
- %User Temp%\_eviip.tmp
- %User Temp%\Honh73353.dll
- %Windows%\Fonts\63b57ca224cef4f987fc987475f15507.dat
- %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.. %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.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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
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
Step 3
Delete this registry key
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\Honhserver
- Parameters
- In HKEY_LOCAL_MACHINE\SOFTWARE\rising
- KaKa
- In HKEY_CURRENT_USER\Software\FlySky\E
- Install
Step 4
Delete this registry value
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\Honhserver\Parameters
- Application = "%System%\Honhcservice.exe"
Step 5
Search and delete these files
- %User Temp%\BClib\krnln.fnr
- %User Temp%\BClib\Exmlrpc.fne
- %User Temp%\BClib\dp1.fne
- %System%\Honhcservice.exe
- %System Root%\del_filme.bat
- %System%\Honhcservice.dll
- %User Temp%\_eviip.tmp
- %User Temp%\Honh73353.dll
- %Windows%\Fonts\63b57ca224cef4f987fc987475f15507.dat
- %User Temp%\BClib\krnln.fne
Step 6
Search and delete this folder
- %User Temp%\BClib
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_FLYSTUDI.BA. 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 8
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%\DEL_FI~1.BAT
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