ALIASES:

PWS:Win32/Cimuz.D (Microsoft); Suspicious.SillyFDC (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Trojan.Dropper.Delf.HT (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: 373,760 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 08 Dec 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.

Autostart Technique

This Trojan registers itself as a BHO to ensure its automatic execution every time Internet Explorer is used by adding the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
browser helper objects\{21384D29-1240-2d4f-A15C-17E42823D523}

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
load

HKEY_CLASSES_ROOT\AppID\{21384D29-1240-2d4f-A15C-17E42823D523}

HKEY_CLASSES_ROOT\CLSID\{21384D29-1240-2d4f-A15C-17E42823D523}

HKEY_CLASSES_ROOT\CLSID\{21384D29-1240-2d4f-A15C-17E42823D523}\
InprocServer32

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\Internet Explorer\IEXPLORE.EXE = "{random characters}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
load
net_insll = "5c2a86"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
load
worg = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Control Panel\
load
cmpid = "{random values}"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
CLSID\{21384D29-1240-2d4f-A15C-17E42823D523}\InprocServer32
ThreadingModel = "apartment"

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Enable Browser Extensions = "yes"

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\FLASHW80_PLUGIN.EXE
  • %User Temp%\UPDATE.EXE
  • %System%\ipv6monl.dll

(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.. %System% is the Windows system folder, which is usually C:\Windows\System32.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine: 9.300

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

Close all opened browser windows

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\Microsoft\Windows\CurrentVersion\Control Panel
    • load
  • In HKEY_CLASSES_ROOT\AppID
    • {21384D29-1240-2d4f-A15C-17E42823D523}
  • In HKEY_CLASSES_ROOT\CLSID
    • {21384D29-1240-2d4f-A15C-17E42823D523}
  • In HKEY_CLASSES_ROOT\CLSID\{21384D29-1240-2d4f-A15C-17E42823D523}
    • InprocServer32

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\SYSTEM\ControlSet001\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\Internet Explorer\IEXPLORE.EXE = "{random characters}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\load
    • net_insll = "5c2a86"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\load
    • worg = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Control Panel\load
    • cmpid = "{random values}"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{21384D29-1240-2d4f-A15C-17E42823D523}\InprocServer32
    • ThreadingModel = "apartment"
  • In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main
    • Enable Browser Extensions = "yes"

Step 5

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%\FLASHW80_PLUGIN.EXE
  • %User Temp%\UPDATE.EXE
  • %System%\ipv6monl.dll

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_BZUB.AY. 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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