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TSPY_ZBOT.SMKU

November 26, 2013
 ALIASES:

VirTool:Win32/Obfuscator.YE (Microsoft); PWS-Zbot.gen.hv (McAfee); Trojan.Win32.Generic!BT (Sunbelt); Gen:Variant.Kazy.70592 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • 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 deletes itself after execution.

  TECHNICAL DETAILS

File Size:

37,376 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

24 May 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 creates the following folders:

  • %User Temp%\www

(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.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
AdobeFlash = "%User Temp%\bttjzae noddns noftp nopop3 nosmtp"

Other System Modifications

This spyware adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Keyboard Layout
Scancode Map = "{random values}"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Tcpip\Parameters\
Interfaces\{0D50FF2A-9D59-41C1-A9AC-EB2C659D36FE}
NameServer = "127.0.0.1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Tcpip\Parameters\
Interfaces\{6D128ACA-CE90-4D8D-B04F-CD01DBA59CE2}
NameServer = "127.0.0.1"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Tcpip\Parameters\
Interfaces\{AD0D37C7-7744-4350-B129-2BFFCE7720CA}
NameServer = "127.0.0.1"

Dropping Routine

This spyware drops the following files:

  • %User Temp%\dumb13148
  • %User Temp%\letza
  • %User Temp%\zwktzjc.cfg
  • %User Temp%\bttjzae
  • %User Temp%\zwktzjc.exe
  • %User Temp%\gzqwb

(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.)

Other Details

This spyware connects to the following possibly malicious URL:

  • http://caros.{BLOCKED}s.in/js/data/encryptedtest.dll

It deletes itself after execution.

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

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

Restart in Safe Mode

[ 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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • AdobeFlash = "%User Temp%\bttjzae noddns noftp nopop3 nosmtp"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Keyboard Layout
    • Scancode Map = "{random values}"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Interfaces\{0D50FF2A-9D59-41C1-A9AC-EB2C659D36FE}
    • NameServer = "127.0.0.1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Interfaces\{6D128ACA-CE90-4D8D-B04F-CD01DBA59CE2}
    • NameServer = "127.0.0.1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Interfaces\{AD0D37C7-7744-4350-B129-2BFFCE7720CA}
    • NameServer = "127.0.0.1"

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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.
  • %User Temp%\dumb13148
  • %User Temp%\letza
  • %User Temp%\zwktzjc.cfg
  • %User Temp%\bttjzae
  • %User Temp%\zwktzjc.exe
  • %User Temp%\gzqwb

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 Temp%\www

Step 6

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