ALIASES:

Worm:Win32/Bolkc.A (Microsoft); Trojan Horse (Symantec); Trojan-Clicker.Win32.Agent.gza (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Generic.4549043 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

  TECHNICAL DETAILS

File Size: 299,078 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 23 Jul 2012

Arrival Details

This Trojan 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 Trojan drops the following copies of itself into the affected system:

  • %System%\Conf\svchost.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

It creates the following folders:

  • %System%\Conf

(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
SVCHOST.EXE = "%System%\Conf\svchost.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput

hkey_current_user\software\microsoft\
directinput\{malware file name}4995252b00049046

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput\MostRecentApplication

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU

It adds the following registry entries:

hkey_current_user\software\microsoft\
directinput\{malware file name}4995252b00049046
Name = "{malware file name}"

hkey_current_user\software\microsoft\
directinput\{malware file name}4995252b00049046
UsesMapper = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput\MostRecentApplication
Name = "{malware file name}"

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput\MostRecentApplication
Id = "{malware file name}4995252b00049046"

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput\MostRecentApplication
Version = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
DirectInput\MostRecentApplication
MostRecentStart = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Enable = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Size = "a"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
InitHits = "64"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\International\CpMRU
Factor = "14"

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.200

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

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_CURRENT_USER\Software\Microsoft
    • DirectInput
  • In hkey_current_user\software\microsoft\directinput
    • {malware file name}4995252b00049046
  • In HKEY_CURRENT_USER\Software\Microsoft\DirectInput
    • MostRecentApplication
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International
    • CpMRU

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
    • SVCHOST.EXE = "%System%\Conf\svchost.exe"
  • In hkey_current_user\software\microsoft\directinput\{malware file name}4995252b00049046
    • Name = "{malware file name}"
  • In hkey_current_user\software\microsoft\directinput\{malware file name}4995252b00049046
    • UsesMapper = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\DirectInput\MostRecentApplication
    • Name = "{malware file name}"
  • In HKEY_CURRENT_USER\Software\Microsoft\DirectInput\MostRecentApplication
    • Id = "{malware file name}4995252b00049046"
  • In HKEY_CURRENT_USER\Software\Microsoft\DirectInput\MostRecentApplication
    • Version = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\DirectInput\MostRecentApplication
    • MostRecentStart = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Enable = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Size = "a"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • InitHits = "64"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\International\CpMRU
    • Factor = "14"

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.
  • %System%\Conf

Step 6

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