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TSPY_ZBOT.VHP
Aliases: Trojan.Zbot.IBN (Bitdefender), Win32/Spy.Zbot.AAO trojan (ESET)
Malware type: Spyware
Destructive: No
Platform: 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)
Encrypted: Yes
In the wild: Yes

Overview


Infection Channel: Downloaded from the Internet, Dropped by other malware

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 is injected into all running processes to remain memory resident.

It modifies registry entries to disable the Windows Firewall settings. This action allows this malware to perform its routines without being deteted by the Windows Firewall.

It does not have any propagation routine.

It does not have any backdoor routine.

It modifies Internet Explorer security settings. This puts the affected computer at greater risk, as it allows malicious URLs to be accessed by the computer.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

It deletes the initially executed copy of itself.

Technical Details


File size: 243,712 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 15 Oct 2013
Payload: Connects to URLs/IPs, Downloads files

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%\{random folder name 2}\{random file name 2}.{random file extension} - contains encrypted stolen information
  • %User Temp%\tmp{random}.bat - Used to delete its initially executed copy

(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.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

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:\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 is injected into all running processes to remain memory resident.

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{GUID}
  • Local\{GUID}

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 GUID} = "%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 adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Privacy
CleanCookies = "0"

It modifies the following registry entries to disable the Windows Firewall settings:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\DomainProfile\AuthorizedApplications\
List
%windir%\explorer.exe = "%windir%\explorer.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%windir%\explorer.exe = "%windir%\explorer.exe"

Propagation

This spyware does not have any propagation routine.

Backdoor Routine

This spyware does not have any backdoor routine.

Web Browser Home Page and Search Page Modification

This spyware modifies Internet Explorer zone settings.

Download Routine

This spyware connects to the following website(s) to download and execute a malicious file:

  • http://feedweb.{BLOCKED}dn.net/feedswebz/html/myupdates.exe

It saves the files it downloads using the following names:

  • %User Temp%\tmp{random number}\myupdates.exe - detected as BKDR_AGENT.BGTI

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

Information Theft

This spyware accesses the following site to download its configuration file:

  • http://feedweb.{BLOCKED}dn.net/feedswebz/html/mysfeeds.php
  • http://{BLOCKED}m1.{random domain}.{random extension}/websfeedz.php

Other Details

This spyware connects to the following URL(s) to check for an Internet connection:

  • http://www.google.com/webhp

It deletes the initially executed copy of itself

NOTES:

Where {random domain} can be any of the following:

  • dnsbinzs
  • dnsmicrosf
  • dnszapps
  • mymicrodns
  • www8binup
  • wwwappdns

and {random extension} can be any of the following:

  • .com
  • .net
  • .org

The configuration file may contain URLs where it downloads an updated copy of itself and where it sends its gathered information. It may also contain URLs of its target online banking and finance-related sites from where it steals the information.

It may also gather the following information from the affected system:

  • Data on Cookie files (URLs)
  • Email information stored in the user’s Windows Address Book (WAB) file
  • Email-related information such as account names, email addresses, passwords, server data, and server port

Solution


Minimum scan engine: 9.300
First VSAPI Pattern File: 10.342.04
First VSAPI Pattern Release Date: 15 Oct 2013
VSAPI OPR Pattern Version: 10.343.00
VSAPI OPR Pattern Release Date: 15 Oct 2013

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

Remove malware/grayware files dropped/downloaded by TSPY_ZBOT.VHP

     
    • TROJ_AGENT.BGTI

Step 3

Restart in Safe Mode

[ Learn more ]

Step 4

Delete this registry key

[ Learn more ]

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}
  • In HKEY_CURRENT_USER\Software\Microsoft
    • WAB

Step 5

Delete this registry value

[ Learn more ]

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 GUID} = "%Application Data%\{random folder name 1}\{random file name 1}.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Privacy
    • CleanCookies = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
    • %windir%\explorer.exe = "%windir%\explorer.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %windir%\explorer.exe = "%windir%\explorer.exe"

Step 6

Search and delete these folders

[ Learn more ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\{random folder name 1}
  • %Application Data%\{random folder name 2}

Step 7

Reset Internet security settings

[ Learn more ]

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TSPY_ZBOT.VHP. 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 9

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.
Analysis By: Automation
Modified By: Anthony Joe Melgarejo

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