Analysis by: Rhena Inocencio

 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

  TECHNICAL DETAILS

File Size: 19,384 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 27 Mar 2012

Installation

This Trojan drops the following files:

  • %System%\drivers\{random file name}.sys

(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 drops the following copies of itself into the affected system:

  • %User Profile%\9iwqj1rup4.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
9iwqj1rup4 = "%User Profile%\9iwqj1rup4.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
ErrorControl = "0"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
ImagePath = "%System%\drivers\{random file name}.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\{random file name}
DisplayName = "9iwqj1rup4.exe"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}at.com
  • {BLOCKED}r.com
  • {BLOCKED}lj.com
  • {BLOCKED}a.com
  • {BLOCKED}dk.com
  • {BLOCKED}mcy.com
  • {BLOCKED}ld.com

  SOLUTION

Minimum Scan Engine: 9.200
FIRST VSAPI PATTERN FILE: 9.172.06
FIRST VSAPI PATTERN DATE: 06 Jun 2012
VSAPI OPR PATTERN File: 9.173.00
VSAPI OPR PATTERN Date: 07 Jun 2012

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

Identify and terminate files detected as TROJ_DROPPER.UZR

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Search and delete this file

[ Learn More ]
There may be some component files 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.  
  • %System%\drivers\{random file name}.sys

Step 5

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
    • 9iwqj1rup4 = "%User Profile%\9iwqj1rup4.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random file name}
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random file name}
    • Start = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random file name}
    • ErrorControl = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random file name}
    • ImagePath = "%System%\drivers\{random file name}.sys"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\{random file name}
    • DisplayName = "9iwqj1rup4.exe"

Step 6

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\SYSTEM\CurrentControlSet\Services
    • {random file name}

Step 7

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