TSPY_ZBOT.SZPA

 Analysis by: Christopher Daniel So

 ALIASES:

PWS:Win32/Zbot (Microsoft), Trojan-Spy.Win32.Zbot.avhz (Kaspersky), Troj/Zbot-AGM (Sophos), Win32/Spy.Zbot.YW (NOD32), Trojan-Spy.Win32.Zbot (Ikarus)

 PLATFORM:

Windows 2000, XP, Server 2003

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Once users access any of the monitored sites, it starts logging keystrokes. It attempts to steal information, such as user names and passwords, used when logging into certain banking or finance-related websites.

  TECHNICAL DETAILS

File Size:

153,088 bytes

File Type:

PE

Memory Resident:

Yes

Initial Samples Received Date:

06 Dec 2010

Payload:

Downloads files, Drops files

Infection Points

This Trojan arrives as a file downloaded from the following URLs:

  • http://{BLOCKED}vanced-cfg2.com/monte-karlo/us.exe

Installation

This Trojan drops the following files:

  • %User Profile%\Application Data\{random1}\{random file name 1}.exe
  • %User Profile%\Application Data\{random2}\{random file name 2}

(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\{random1}
  • %User Profile%\Application Data\{random2}

(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 injects itself into the following processes as part of its memory residency routine:

  • ctfmon.exe
  • dwm.exe
  • explorer.exe
  • rdpclip.exe
  • taskeng.exe
  • taskhost.exe
  • wscntfy.exe

Autostart Technique

This Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random CLSID} = "%User Profile%\Application Data\{random1}\{random file name 1}.exe"

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
{random key}

Information Theft

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

  • http://{BLOCKED}vanced-cfg3.com/monte-karlo/usdase.db
  • http://{BLOCKED}vanced-cfg4.com/monte-karlo/usdase.db
  • http://{BLOCKED}vanced-cfg5.com/monte-karlo/usdase.db

Once users access any of the monitored sites, it starts logging keystrokes.

It attempts to access a website to download a file which contains information where the Trojan can download an updated copy of itself, and where to send its stolen data. This configuration file also contains the following list of targeted bank-related websites from which it steals information:

  • http*chase.com/
  • https://*chase.com/*
  • *wellsfargo.com/
  • *online.wellsfargo.com/login*
  • *www.bankofamerica.com/*
  • *www.bankofamerica.com*
  • htt*://www.citi*com/*

The downloaded file contains information where the malware can download an updated copy of itself, and where to send its stolen data.

Note that the contents of the file, hence the list of websites to monitor, may change any time.

It attempts to steal information from the following banks and/or other financial institutions:

  • Chase
  • Wells Fargo
  • Bank of America
  • Citibank

Stolen Information

This Trojan sends the gathered information via HTTP POST to the following URL:

  • http://{BLOCKED}.{BLOCKED}.197.24/~hosting/woops/ttf.php

Other Details

This Trojan did not exhibit backdoor routines during testing.

Variant Information

This Trojan has the following MD5 hashes:

  • 1bd1b7192983f78924826e1ff5e8c810

It has the following SHA1 hashes:

  • b866064cb704701243c08d793b42ca2d0d7a5a0c

  SOLUTION

Minimum Scan Engine:

8.900

VSAPI PATTERN File:

7.682.11

VSAPI PATTERN Date:

06 Dec 2010

VSAPI PATTERN Date:

12/6/2010 12:00:00 AM

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

Identify and delete files detected as TSPY_ZBOT.SZPA using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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 CLSID}=%User Profile%\Application Data\{random1}\{random file name 1}.exe

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 key}

Step 5

Search and delete this folder

[ 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.  
  • %User Profile%\Application Data\{random1}
  • %User Profile%\Application Data\{random2}

Step 6

Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.SZPA. 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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