TROJ_EASTWD.WIL
Trojan:Win32/Estiwir (Microsoft); HEUR:Trojan.Win32.Generic (Kaspersky); Trojan-Dropper.Win32.OnlineGames.qcf (v) (Sunbelt); Win32/Heur (AVG)
Windows
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
1,252,919 bytes
EXE
Yes
14 Jan 2015
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 drops the following copies of itself into the affected system:
- %User Temp%\6699.tmp
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It creates the following folders:
- %User Temp%\yhsys
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
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\1a303ecb
Other System Modifications
This Trojan deletes the following files:
- %User Profile%\Cookies\index.dat
- %System%\Drivers\EstRtw.sys
- %User Temp%\6d11.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)
It adds the following registry keys:
HKEY_CLASSES_ROOT\CLSID\HOOK_ID
HKEY_CLASSES_ROOT\CLSID\SYS_DLL
It adds the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\HOOK_ID
name = "6d11.exe"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\1a303ecb
Type = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\1a303ecb
ErrorControl = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\1a303ecb
Start = "1"
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\1a303ecb
ImagePath = "\??\%System%\drivers\1a303ecb.sys"
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\SYS_DLL
name = "Jty.dll"
It deletes the following registry keys:
HKEY_CLASSES_ROOT\CLSID\TANG2_OTP
HKEY_CLASSES_ROOT\CLSID\HOK_OTP
HKEY_CLASSES_ROOT\CLSID\TANG1_NCP
HKEY_CLASSES_ROOT\CLSID\TANG1_URL
HKEY_CLASSES_ROOT\CLSID\AH3SEC
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects\{18DF081C-E8AD-4283-A596-FA578C2EBDC3}
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Browser Helper Objects
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\1a303ecb\Enum
HKEY_LOCAL_MACHINE\System\CurrentControlSet\
Services\1a303ecb\Security
Dropping Routine
This Trojan drops the following files:
- %User Temp%\6d11.exe
- QBridgeUpdate.log
- {malware file name}.log
- %System Root%\mu.dll
- %System Root%\qbridge.ini
- %User Temp%\A1.zip
- %User Temp%\B1.zip
- %User Temp%\C1.zip
- %User Temp%\D1.zip
- %User Temp%\yhsys\doit.rar
- %System%\drivers\1a303ecb.sys
- %User Temp%\rdtuEfuFe.dll
- %User Temp%\Jty.dll
- %User Temp%\tCyuw.dll
- %System%\ws2tcpip.dll
(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://down.{BLOCKED}e.co.kr/update/QBridge_VER.html
- http://{BLOCKED}9.175.157/mail.asp?{random characters}
It deletes itself after execution.
This report is generated via an automated analysis system.
SOLUTION
9.700
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
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
- 1a303ecb
- In HKEY_CLASSES_ROOT\CLSID
- HOOK_ID
- In HKEY_CLASSES_ROOT\CLSID
- SYS_DLL
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\Classes\CLSID\HOOK_ID
- name = "6d11.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\1a303ecb
- Type = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\1a303ecb
- ErrorControl = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\1a303ecb
- Start = "1"
- In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\1a303ecb
- ImagePath = "\??\%System%\drivers\1a303ecb.sys"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\SYS_DLL
- name = "Jty.dll"
Step 5
Search and delete these components
- %User Temp%\6d11.exe
- QBridgeUpdate.log
- {malware file name}.log
- %System Root%\mu.dll
- %System Root%\qbridge.ini
- %User Temp%\A1.zip
- %User Temp%\B1.zip
- %User Temp%\C1.zip
- %User Temp%\D1.zip
- %User Temp%\yhsys\doit.rar
- %System%\drivers\1a303ecb.sys
- %User Temp%\rdtuEfuFe.dll
- %User Temp%\Jty.dll
- %User Temp%\tCyuw.dll
- %System%\ws2tcpip.dll
Step 6
Search and delete this folder
- %User Temp%\yhsys
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TROJ_EASTWD.WIL. 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.
- %User Profile%\Cookies\index.dat
- %System%\Drivers\EstRtw.sys
- %User Temp%\6d11.exe
Step 9
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_CLASSES_ROOT\CLSID
- TANG2_OTP
- In HKEY_CLASSES_ROOT\CLSID
- HOK_OTP
- In HKEY_CLASSES_ROOT\CLSID
- TANG1_NCP
- In HKEY_CLASSES_ROOT\CLSID
- TANG1_URL
- In HKEY_CLASSES_ROOT\CLSID
- AH3SEC
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects
- {18DF081C-E8AD-4283-A596-FA578C2EBDC3}
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer
- Browser Helper Objects
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\1a303ecb
- Enum
- In HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\1a303ecb
- Security
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