TROJ_DROPPER.XXTTT


 ALIASES:

RDN/Generic Dropper!wt (McAfee); Trojan.Klovbot (Symantec); Trojan-Ransom.Win32.Foreign.mfzj (Kaspersky); Mal/RarMal-E (Sophos); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

 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:

628,006 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

12 May 2015

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 creates the following folders:

  • %System Root%\Documents and Settings\Wilbert
  • %System Root%\Documents

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\WinRAR SFX

It adds the following registry entries:

HKEY_CURRENT_USER\Software\WinRAR SFX
C%%Documents and Settings%Wilbert%Application Data = "%User Profile%\Application Data"

Dropping Routine

This Trojan drops the following files:

  • __tmp_rar_sfx_access_check_28718
  • app.bat
  • good.sfx.exe
  • __tmp_rar_sfx_access_check_35062
  • good.exe

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.750

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

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
    • WinRAR SFX

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_CURRENT_USER\Software\WinRAR SFX
    • C%%Documents and Settings%Wilbert%Application Data = "%User Profile%\Application Data"

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.
  • __tmp_rar_sfx_access_check_28718
  • app.bat
  • good.sfx.exe
  • __tmp_rar_sfx_access_check_35062
  • good.exe

Step 5

Search and delete these folders

[ 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 Root%\Documents and Settings\Wilbert
  • %System Root%\Documents

Step 6

Scan your computer with your Trend Micro product to delete files detected as TROJ_DROPPER.XXTTT. 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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