TSPY_ZBOT.GBX
PWS:Win32/Zbot.gen!Y (Microsoft); PWS-Zbot.gen.db (McAfee); Trojan-Spy.Win32.Zbot.bckm (Kaspersky); Trojan-Spy.Win32.Zbot.yy (GFI-Sunbelt); Win32/Spy.Zbot.YW trojan (Nod32)
Windows 2000, Windows XP, Windows Server 2003

Threat Type: Spyware
Destructiveness: No
Encrypted: Yes
In the wild: Yes
OVERVIEW
This spyware may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.
It may be injected into processes running in memory.
It opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
It modifies the Internet Explorer Zone Settings.
As of this writing, the said sites are inaccessible.
It attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.
TECHNICAL DETAILS
Arrival Details
This spyware may be dropped by other malware.
It may be unknowingly downloaded by a user while visiting malicious websites.
Installation
This spyware drops the following copies of itself into the affected system:
- %User Profile%\Application Data\{random folder name 1}\{random file name 1}.exe
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It drops the following files:
- %User Profile%\Application Data\{random folder name 2}\{random file name 2}.{3 random alphabetic character extension name} - encrypted data
(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
It creates the following folders:
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Windows\Profiles\{user name}\Application Data on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Application Data on Windows NT, and C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003.)
It is injected into the following processes running in memory:
- ctfmon.exe
- dwm.exe
- explorer.exe
- rdpclip.exe
- taskeng.exe
- taskhost.exe
- wscntfy.exe
It may be injected into processes running in memory.
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
{GUID} = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
Other System Modifications
This spyware adds the following registry keys as part of its installation routine:
HKEY_CURRENT_USER\Software\Microsoft\
{random key}
It creates the following registry entry(ies) to bypass Windows Firewall:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
Backdoor Routine
This spyware opens a random port to allow a remote user to connect to the affected system. Once a successful connection is established, the remote user executes commands on the affected system.
Web Browser Home Page and Search Page Modification
This spyware modifies the Internet Explorer Zone Settings.
Download Routine
As of this writing, the said sites are inaccessible.
Information Theft
This spyware attempts to steal sensitive online banking information, such as user names and passwords. This routine risks the exposure of the user's account information, which may then lead to the unauthorized use of the stolen data.
It accesses the following site to download its configuration file:
- http://{random domain name}/news/?s={random number}
NOTES:
This spyware sends all gathered information using HTTP POST to the URL contained in its configuration file.
It is also capable of generating domain names, using pseudorandom alphanumeric characters that are computed from the current UTC system date and time where it connects to download its configuration file.
SOLUTION
Step 1
For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.
Step 2
Restart in Safe Mode
Step 3
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
- {GUID} = %Application Data%\{random folder name 1}\{random file name 1}.exe
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = %Windows%\explorer.exe:*:Enabled:Windows Explorer
Step 4
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 key}
Step 5
Search and delete this folder
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
Step 6
Reset Internet security settings
Step 7
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.GBX. 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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