TSPY_ZBOT.ESB
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.
TECHNICAL DETAILS
495,616 bytes
EXE
Yes
12 Jan 2012
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 2}\{random file name}.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 1}\{random file name}.{3 random alphabetic character extension name}
(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.)
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 2}\{random file name}.exe"
Other System Modifications
This spyware adds the following registry keys:
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 = "%windir%\explorer.exe"
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%windir%\explorer.exe"
SOLUTION
8.900
8.704.09
13 Jan 2012
8.705.00
13 Jan 2012
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.ESB
Step 3
Restart in Safe Mode
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
- {GUID} = "%Application Data%\{random folder name 2}\{random file name}.exe"
- {GUID} = "%Application Data%\{random folder name 2}\{random file name}.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = "%windir%\explorer.exe"
- %Windows%\explorer.exe = "%windir%\explorer.exe"
- In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
- %Windows%\explorer.exe = "%windir%\explorer.exe"
- %Windows%\explorer.exe = "%windir%\explorer.exe"
Step 5
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 6
Search and delete the file detected as TSPY_ZBOT.ESB
Step 7
Search and delete these folders
- %Application Data%\{random folder name 1}
- %Application Data%\{random folder name 2}
Step 8
Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.ESB . 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.
NOTES:
The created registry key HKEY_CURRENT_USER\Software\Microsoft\{random} cannot be identified by the users 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 if the users have one. Note that the key, {random} need not to be deleted since it won't cause the user system any harm.
In deleting the created folders, please take note of the malware path of the file(s) detected earlier.
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