BKDR_VAWTRAK.YUY
Backdoor:Win32/Vawtrak.D (Microsoft); Trojan-FDYM!66B5CB6A7944 (McAfee); Trojan-Spy.Win32.SpyEyes.amqd (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse SHeur4.BTDQ (AVG)
Windows 2000, Windows XP, Windows Server 2003
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
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:
- %System Root%\spoolerlogs
- %User Profile%\Application Data\VMware
- %User Profile%\VMware\VMware Tools
(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.)
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
czcjhh = "regsvr32.exe %User Profile%\Application Data\czcjhh.dat "
Other System Modifications
This backdoor adds the following registry keys:
HKEY_CURRENT_USER\SOFTWARE\Classes\
CLSID\{117A5899-70DC-4EA0-B35F-15F35AEF383F}
It adds the following registry entries:
HKEY_CURRENT_USER\CLSID\{117A5899-70DC-4EA0-B35F-15F35AEF383F}
#sd = "{random values}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
LogSessionName = "stdout"
(Note: The default value data of the said registry entry is {random values}.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
Active = "1"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi
ControlFlags = "1"
(Note: The default value data of the said registry entry is 1.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"
(Note: The default value data of the said registry entry is 8107d8e9-e323-49f5-bba2-abc35c243dca.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Tracing\
Microsoft\Imapi\ImapiSvc
BitNames = "{random characters}"
(Note: The default value data of the said registry entry is ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort.)
Dropping Routine
This backdoor drops the following files:
- %User Profile%\Application Data\czcjhh.dat
- %System Root%\spoolerlogs\spooler.xml
- %Temp%\k88t22ps.TMP
(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 Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Temp% is the Windows Temporary folder, which is usually C:\Windows\Temp.)
This report is generated via an automated analysis system.
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
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_CURRENT_USER\SOFTWARE\Classes\CLSID
- {117A5899-70DC-4EA0-B35F-15F35AEF383F}
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
- czcjhh = "regsvr32.exe %User Profile%\Application Data\czcjhh.dat "
- In HKEY_CURRENT_USER\CLSID\{117A5899-70DC-4EA0-B35F-15F35AEF383F}
- #sd = "{random values}"
Step 5
Restore these modified registry values
Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
- From: LogSessionName = "stdout"
To: LogSessionName = ""{random values}""
- From: LogSessionName = "stdout"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
- From: Active = "1"
To: Active = ""1""
- From: Active = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi
- From: ControlFlags = "1"
To: ControlFlags = ""1""
- From: ControlFlags = "1"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
- From: Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"
To: Guid = ""8107d8e9-e323-49f5-bba2-abc35c243dca""
- From: Guid = "8107d8e9-e323-49f5-bba2-abc35c243dca"
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Tracing\Microsoft\Imapi\ImapiSvc
- From: BitNames = "{random characters}"
To: BitNames = "" ImapiDebugError ImapiDebugWarning ImapiDebugTrace ImapiDebugInfo ImapiDebugX ImapiDebugSort""
- From: BitNames = "{random characters}"
Step 6
Search and delete these components
- %User Profile%\Application Data\czcjhh.dat
- %System Root%\spoolerlogs\spooler.xml
- %Temp%\k88t22ps.TMP
Step 7
Search and delete these folders
- %System Root%\spoolerlogs
- %User Profile%\Application Data\VMware
- %User Profile%\VMware\VMware Tools
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as BKDR_VAWTRAK.YUY. 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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