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TSPY_ZBOT.MDN
Aliases: PWS:Win32/Zbot.gen!Y (Microsoft)
Malware type: Spyware
Destructive: No
Platform: Windows 2000, Windows XP, Windows Server 2003
Encrypted: Yes
In the wild: Yes

Overview


This spyware arrives as an attachment to email messages spammed by other malware/grayware or malicious users. It may be unknowingly downloaded by a user while visiting malicious websites.

It modifies the Internet Explorer Zone Settings.

Technical Details


File size: 203,264 bytes
File type: EXE
Memory resident: Yes
Initial samples received date: 30 Jan 2012

Arrival Details

This spyware arrives as an attachment to email messages spammed by other malware/grayware or malicious users.

It may be unknowingly downloaded by a user while visiting malicious websites.

Installation

This spyware drops the following files:

  • %Application Data%\{random2}\{random}.{random ext}

(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 copies of itself into the affected system:

  • %Application Data%\{random1}\{random}.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 creates the following folders:

  • %Application Data%\{random1}
  • %Application Data%\{random2}

(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.)

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%\{random1}\{random}.exe"

Other System Modifications

This spyware adds the following registry keys as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
{random}

Web Browser Home Page and Search Page Modification

This spyware modifies the Internet Explorer Zone Settings.

Information Theft

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

  • http://{BLOCKED}or.ru/makedocs.php

Solution


Minimum scan engine: 9.200
First VSAPI Pattern File: 8.744.05
First VSAPI Pattern Release Date: 30 Jan 2012
VSAPI OPR Pattern Version: 8.745.00
VSAPI OPR Pattern Release Date: 30 Jan 2012

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

Scan your computer with your Trend Micro product and note files detected as TSPY_ZBOT.MDN

Step 3

Restart in Safe Mode

[ Learn more ]

Step 4

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
    • {GUID} = %Application Data%\{random1}\{random}.exe

Step 5

Search and delete this file

[ Learn more ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden files and folders in the search result.
  • %Application Data%\{random2}\{random}.{random ext}

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%\{random1}
  • %Application Data%\{random2}

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.MDN. 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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Analysis By: Michael Cabel

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