TSPY_ZBOT.BT
PWS:Win32/Zbot (Microsoft), Trojan-Spy.Win32.Zbot.eyae (Kaspersky), Suspicious:W32/Malware!Gemini (FSecure), Trojan.Win32.Generic!BT (Sunbelt), TR/Spy.ZBot.eyae (Antivir), a variant of Win32/Kryptik.AMAM trojan (NOD32)
Windows 2000, Windows XP, Windows Server 2003
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 modifies the Internet Explorer Zone Settings.
As of this writing, the said sites are inaccessible.
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 a copy of itself in the following folders using different file names:
- %User Profile%\Application Data\{Random Folder 1}\{Random Filename}.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 non-malicious file:
- %User Profile%\Application Data\{Random Folder 2}\{Random Filename and Extension}
- %User Profile%\Application Data\{Random Folder 3}\{Random Filename and Extension}
(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:
- %User Profile%\Application Data\{Random Folder 1}
- %User Profile%\Application Data\{Random Folder 2}
- %User Profile%\Application Data\{Random Folder 3}
(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.)
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 characters} = "%User Profile%\Application Data\{Random Folder 1}\{Random Filename}.exe"
Other System Modifications
This spyware 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"
Web Browser Home Page and Search Page Modification
This spyware modifies the Internet Explorer Zone Settings.
Download Routine
This spyware connects to the following URL(s) to download its component file(s):
- {BLOCKED}ec948fa2bc.com
As of this writing, the said sites are inaccessible.
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
Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.BT
Step 3
Restart in Safe Mode
Step 4
Search and delete these folders
- %User Profile%\Application Data\{Random Folder 1}
- %User Profile%\Application Data\{Random Folder 2}
- %User Profile%\Application Data\{Random Folder 3}
Step 5
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 characters} = "%User Profile%\Application Data\{Random Folder 1}\{Random Filename}.exe"
- {random characters} = "%User Profile%\Application Data\{Random Folder 1}\{Random Filename}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
- %Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"
Step 6
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.BT. 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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