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TSPY_ZBOT.SMES

November 26, 2013
 Modified by: Michael Cabel
 ALIASES:

PWS:Win32/Zbot.gen!Y (Microsoft); Trojan.Zbot (Symantec); PWS-Zbot.gen.hb (McAfee);

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW


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 does not have any propagation routine.

It does not have any backdoor routine.

It modifies the Internet Explorer Zone Settings.

It terminates itself if it detects it is being run in a virtual environment. However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

202,752 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

28 Feb 2012

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 files:

  • %Application Data%\{random letters 1}\{random letters}.exe - copy of itself
  • %Application Data%\{random letters 2}\{random letters}.{random letters} - encrypted file

(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%\{random letters 1}
  • %Application Data%\{random letters 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 adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{random GUID}
  • Local\{random GUID}

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

  • explorer.exe

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 letters 1}\{random letters}.exe"

Other System Modifications

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

HKEY_CURRENT_USER\Software\Microsoft\
{random letters}

It creates the following registry entry(ies) to bypass Windows Firewall:

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

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\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 the Internet Explorer Zone Settings.

Download Routine

This spyware connects to the following URL(s) to download its configuration file:

  • http://{BLOCKED}6.com

Information Theft

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

    Other Details

    This spyware terminates itself if it detects it is being run in a virtual environment.

    However, as of this writing, the said sites are inaccessible.

    NOTES:

    This spyware may access a remote site to download its configuration file. It may monitor several finance-related institutions depending on the contents of the configuration file. The configuration file also contains the drop zone where it sends stolen information, the URL where the configuration file can be downloaded, the codes for web inject, and the monitored URLs. However, due to errors in its code, it fails to perform its intended routine.

      SOLUTION

    Minimum Scan Engine:

    9.200

    FIRST VSAPI PATTERN FILE:

    8.806.06

    FIRST VSAPI PATTERN DATE:

    28 Feb 2012

    VSAPI OPR PATTERN File:

    8.807.00

    VSAPI OPR PATTERN Date:

    29 Feb 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.SMES

    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} = "%User Profile%\Application Data\{random folder name 1}\{random file name 1}.exe"
    • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\DomainProfile\AuthorizedApplications\List
      • %Windows%\explorer.exe = "%Windows%\explorer.exe"
    • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
      • %Windows%\explorer.exe = "%Windows%\explorer.exe"

    Step 5

    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. Before you could do this, you must restart in Safe Mode. For instructions on how to do this, you may refer to this page If the preceding step requires you to restart in safe mode, you may proceed to edit the system registry.

    • In HKEY_CURRENT_USER\Software\Microsoft
      • {random letters}

    Step 6

    Reset Internet security settings

    [ Learn More ]

    Step 7

    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 letters 1}
    • %Application Data%\{random letters 2}

    Step 8

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

    Scan your computer with your Trend Micro product to delete files detected as TSPY_ZBOT.SMES. 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 letters} 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 letters} 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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