TSPY_ZBOT.MFO
Backdoor:Win32/Ursap!rts (Microsoft), PWS-Zbot.dx (McAfee), W32/Zbot.HKJM!tr (Fortinet), Trojan-Downloader.Win32.Andromeda (Ikarus), TrojanSpy.Zbot.hkjm (VBA32), Win32/Injector.AAKU trojan (NOD32), Trj/Sinowal.WWG (Panda)
Windows 2000, Windows XP (32-bit and 64-bit), Windows Server 2003, Windows Vista (32-bit and 64-bit), Windows 7 (32-bit and 64-bit)
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.
It deletes the initially executed copy of itself.
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:
- %Application Data%\{random folder name 1}\{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\winxp.wab - {for non-Windows Vista and 7 only}
- %Application Data%\Microsoft\Address Book\winxp.wab~ - {for non-Windows Vista and 7 only}
- %Application Data%\{random folder name 2}\{random file name 2}.{random file extension}
(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 creates the following folders:
- %Application Data%\{random folder name 1}
- %Application Data%\Microsoft\Address Book
- %AppDataLocal%\Microsoft\Windows\WIndows Mail\Local Folders - {for Windows Vista and 7 only}
- %Application Data%\{random folder name 2}
(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.. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local 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 CLSID} = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
Other System Modifications
This spyware adds the following registry keys:
HKEY_CURRENT_USER\Software\Microsoft\
{random}
HKEY_CURRENT_USER\Software\Microsoft\
WAB
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%windir%\explorer.exe = "%windir%\explorer.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%windir%\explorer.exe = "%windir%\explorer.exe"
Other Details
This spyware deletes the initially executed copy of itself
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\Microsoft
- {random}
- {random}
- 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 CLSID} = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
- {random CLSID} = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %windir%\explorer.exe = "%windir%\explorer.exe"
- %windir%\explorer.exe = "%windir%\explorer.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
- %windir%\explorer.exe = "%windir%\explorer.exe"
- %windir%\explorer.exe = "%windir%\explorer.exe"
Step 5
Search and delete these folders
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
- %Application Data%\Microsoft\Address Book
- %AppDataLocal%\Microsoft\Windows\WIndows Mail\Local Folders
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.MFO. 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 7
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}
Did this description help? Tell us how we did.