BKDR_NETWIRED.XXL
Win32.Backdoor.Netwire.Kiuy (Tencent)
Windows
Threat Type: Backdoor
Destructiveness: No
Encrypted: Yes
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.
It executes commands from a remote malicious user, effectively compromising the affected system.
TECHNICAL DETAILS
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 drops the following copies of itself into the affected system and executes them:
- %Application Data%\Install\Host.exe
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 drops the following files:
- %User Temp%\subfolder\hfgfhdg.exe - modified copy of itself
- %Application Data%\Install\.Identifier
(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.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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 mutexes to ensure that only one of its copies runs at any one time:
- hEGpnAVx
Autostart Technique
This backdoor adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
NetWire = "%Application Data%\Install\Host.exe"
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{4J0HKAK2-LMY3-NXM3-5GYE-6AYHF5Y0FH30}
StubPath = "%Application Data%\Install\Host.exe"
It drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:
- hfgfhdg.vbs
Backdoor Routine
This backdoor executes the following commands from a remote malicious user:
- Download & execute files on the affected system
- Execute Command Shell
- List files on a directory
- Terminate Processes
- Perform keylogging routine
It connects to the following URL(s) to send and receive commands from a remote malicious user:
- {BLOCKED}.{BLOCKED}.131.212:3365
Dropping Routine
This backdoor drops the following file(s), which it uses for its keylogging routine:
- %Application Data%\Logs\{DD-MM-YYYY}
(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming 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.)
Information Theft
This backdoor attempts to steal stored email credentials from the following:
- Windows Live Mail
- Microsoft Outlook
It attempts to get stored information such as user names, passwords, and hostnames from the following browsers:
- Mozilla Firefox
- Mozilla Thunderbird
- Mozilla SeaMonkey
- Opera
- Internet Explorer
- Google Chrome
SOLUTION
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
Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.
Step 3
Restart in Safe Mode
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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- NetWire = "%Application Data%\Install\Host.exe"
- NetWire = "%Application Data%\Install\Host.exe"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Active Setup\Installed Components\{4J0HKAK2-LMY3-NXM3-5GYE-6AYHF5Y0FH30}
- StubPath = "%Application Data%\Install\Host.exe"
- StubPath = "%Application Data%\Install\Host.exe"
Step 5
Search and delete this file
- %Application Data%\Install\.Identifier
- %Application Data%\Logs\{DD-MM-YYYY}
- %User Temp%\subfolder\hfgfhdg.exe
- %User Startup%\hfgfhdg.vbs
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_NETWIRED.XXL. 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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