TSPY_ZBOT.YUYEN


 ALIASES:

PWS:Win32/Zbot (Microsoft); Trojan.Gen.2 (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Trojan horse SHeur4.BWMB (AVG)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 INFORMATION EXPOSURE:

  • Threat Type: Spyware

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet


This ZeuS variant uses random headers and changes its file extension, making it difficult to detect.

To get a one-glance comprehensive view of the behavior of this Spyware, refer to the Threat Diagram shown below.

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:

310,784 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

06 Jun 2014

Payload:

Drops files

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 Profile%\Application Data\Ciusmie

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} 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
Ilehuruhyqa = "%User Profile%\Ciusmie\ogxym.exe "

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Ilehuruhyqa = "%User Profile%\Ciusmie\ogxym.exe "

Other System Modifications

This spyware adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Chcvifhsno

HKEY_CURRENT_USER\SOFTWARE\Chcvifhsno

HKEY_CURRENT_USER\SOFTWARE\AVygrA

HKEY_LOCAL_MACHINE\SOFTWARE\AVygrA

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Chcvifhsno
License = "1bc"

HKEY_CURRENT_USER\Software\Chcvifhsno
License = "1bc"

HKEY_CURRENT_USER\Software\AVygrA
dynamicdata = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\AVygrA
dynamicdata = "{random values}"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\Session Manager\SubSystems
Windows = "{random characters}"

(Note: The default value data of the said registry entry is {random values}.)

Dropping Routine

This spyware drops the following files:

  • %User Profile%\Ciusmie\ogxym.exe
  • %Windows%\Tasks\Security Center Update - 404626534.job
  • %System%\cyneohow.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %Windows% is the Windows folder, which is usually C:\Windows.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

Other Details

This spyware connects to the following possibly malicious URL:

  • http://{BLOCKED}uck.su
  • http://{BLOCKED}uck.su/b/letr/19149A6E80C97DCCB2CFD3CD
  • {BLOCKED}.79.185

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.842.02

FIRST VSAPI PATTERN DATE:

05 Jun 2014

VSAPI OPR PATTERN File:

10.849.00

VSAPI OPR PATTERN Date:

09 Jun 2014

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 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_LOCAL_MACHINE\SOFTWARE
    • Chcvifhsno
  • In HKEY_CURRENT_USER\SOFTWARE
    • Chcvifhsno
  • In HKEY_CURRENT_USER\SOFTWARE
    • AVygrA
  • In HKEY_LOCAL_MACHINE\SOFTWARE
    • AVygrA

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_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Ilehuruhyqa = "%User Profile%\Ciusmie\ogxym.exe "
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Ilehuruhyqa = "%User Profile%\Ciusmie\ogxym.exe "
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Chcvifhsno
    • License = "1bc"
  • In HKEY_CURRENT_USER\Software\Chcvifhsno
    • License = "1bc"
  • In HKEY_CURRENT_USER\Software\AVygrA
    • dynamicdata = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\AVygrA
    • dynamicdata = "{random values}"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\SubSystems
    • From: Windows = "{random characters}"
      To: Windows = ""{random values}""

Step 6

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 Profile%\Ciusmie\ogxym.exe
  • %Windows%\Tasks\Security Center Update - 404626534.job
  • %System%\cyneohow.exe

Step 7

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\Ciusmie

Step 8

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