TSPY_ZBOT.SM44
PWS:Win32/Zbot.gen!GO(Microsoft), Trojan.Zbot(Symantec), PWSZbot-FTY!2F8BD741C1BE(McAfee), Troj/Wonton-AV(Sophos), a variant of Win32/Kryptik.BYPL trojan(Eset)
Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Spyware
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This spyware 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 spyware 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 spyware drops the following copies of itself into the affected system and executes them:
- %Application Data%\{random folder}\{random file name 1}.exe
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
It drops the following files:
- %Application Data%\Microsoft\Address Book\{user name}.wab
- %System%\drivers\{random file name 2}.sys
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %System% is the Windows system folder, which is usually C:\Windows\System32.)
It creates the following folders:
- %Application Data%\{random folder}
- %Application Data%\Microsoft\Address Book
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)
Autostart Technique
This spyware adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random file name 1} = "%Application Data%\{random folder}\{random file name 1}.exe"
It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry entries:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name 2}
DisplayName = "{malware file name}.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name 2}
ImagePath = %System%\drivers\{random file name 2}.sys
It registers its dropped component as a system service to ensure its automatic execution at every system startup. It does this by creating the following registry keys:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name 2}
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
HKEY_CURRENT_USER\Software\Microsoft\
WAB
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
{random} = "{random}"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkContactRefresh = "0"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4
OlkFolderRefresh = "0"
HKEY_CURRENT_USER\Software\Microsoft\
WAB\WAB4\Wab File Name
(Default) = "%Application Data%\Microsoft\Address Book\{user name}.wab"
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{random port 1}:UDP = "{random port 1}:UDP:*:Enabled:UDP {random port 1}"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\GloballyOpenPorts\
List
{random port 2}:TCP = "{random port 2}:TCP:*:Enabled:TCP {random port 2}"
NOTES:
This spyware connects to randomly generated URLs.
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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
- {random file name 2}
- {random file name 2}
- In HKEY_CURRENT_USER\Software\Microsoft
- WAB
- WAB
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
- {random file name 1} = "%Application Data%\{random folder}\{random file name 1}.exe"
- {random file name 1} = "%Application Data%\{random folder}\{random file name 1}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {random port 1}:UDP = "{random port 1}:UDP:*:Enabled:UDP {random port 1}"
- {random port 1}:UDP = "{random port 1}:UDP:*:Enabled:UDP {random port 1}"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\GloballyOpenPorts\List
- {random port 2}:TCP = "{random port 2}:TCP:*:Enabled:TCP {random port 2}"
- {random port 2}:TCP = "{random port 2}:TCP:*:Enabled:TCP {random port 2}"
Step 5
Search and delete these folders
- %Application Data%\{random folder}
- %Application Data%\Microsoft\Address Book
Step 6
Search and delete these files
- %System%\drivers\{random file name 2}.sys
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.SM44. 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
The following created registry key(s) cannot be identified by the user since there are no reference values in the created key. The only way it can be identified is by comparing the present keys with a backup of the system registry. Note that the said key(s) do not have to be deleted since it won't be harmful to the system:
- HKEY_CURRENT_USER\Software\Microsoft\{random}
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