TSPY_ZBOT.EZN

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 executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

It deletes the initially executed copy of itself.

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:

• %User Temp%\{random folder}\{random file name}.exe

(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 drops the following file(s)/component(s):

• %User Temp%\{random file name 3}.bat - used to delete the initially executed copy

(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 creates the following folders:

• %User Temp%\{random folder}

(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 injects codes into the following process(es):

• explorer.exe

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

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 string} = "%User Temp%\{random folder}\{random file name}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random key}

Dropping Routine

This spyware drops the following files:

• %System%\drivers\{random file name 2}.sys - detected by Trend Micro as RTKT_NECURS.BGSG

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

Other Details

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

• http://www.google.com
• http://www.bing.com

It deletes the initially executed copy of itself

NOTES:

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.

This spyware may also gather the following information from the affected system:

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

This spyware connects to random generated IP addresses. It sends out DNS queries to a randomized domain name with the following extensions:

• .info
• .com
• .biz
• .org
• .net
• .ru

It connects to randomized domain name with the format {pseudorandom characters}.{extension}.