ALIASES:

Backdoor:Win32/Dokstormac.A (Microsoft); Trojan-Dropper.Win32.Injector.lxne (Kaspersky); Mal/MSIL-NX (Sophos)

 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: 1,451,488 bytes
File Type: EXE
Memory Resident: Yes
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 drops the following copies of itself into the affected system:

  • %User Profile%\Mircosoft\Mircosoft.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.)

It creates the following folders:

  • %System Root%\Documents and Settings\Wilbert
  • %User Profile%\Application Data\Mircosoft
  • %User Profile%\Mircosoft\logs
  • %User Profile%\Mircosoft\IML

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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 Trojan adds the following registry entries to enable its automatic execution at every system startup:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Intel(R) HDD Protection = "%User Profile%\Mircosoft\Mircosoft.exe"

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Intel(R) HDD Protection

It adds the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft
1380 = "{random characters}"

HKEY_CURRENT_USER\Software\Microsoft
1724 = "{random characters}"

HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
ID = "EsIb3oE25lf42IG7xxBZihkb59O4UfT"

HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
INDT = "28.04.2015"

HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
RLN = "3208.enc"

HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
PX = "1724"

Dropping Routine

This Trojan drops the following files:

  • %User Profile%\Application Data\xxx.html
  • %User Profile%\Mircosoft\asl.avf
  • %User Profile%\Application Data\1.html

(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.)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://www.{BLOCKED}e.com/file.avf
  • {BLOCKED}.162.31
  • {BLOCKED}4.121.48

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

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
    • Intel(R) HDD Protection

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Intel(R) HDD Protection = "%User Profile%\Mircosoft\Mircosoft.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft
    • 1380 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Microsoft
    • 1724 = "{random characters}"
  • In HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
    • ID = "EsIb3oE25lf42IG7xxBZihkb59O4UfT"
  • In HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
    • INDT = "28.04.2015"
  • In HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
    • RLN = "3208.enc"
  • In HKEY_CURRENT_USER\Software\Intel(R) HDD Protection
    • PX = "1724"

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 Profile%\Application Data\xxx.html
  • %User Profile%\Mircosoft\asl.avf
  • %User Profile%\Application Data\1.html

Step 6

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
  • %User Profile%\Application Data\Mircosoft
  • %User Profile%\Mircosoft\logs
  • %User Profile%\Mircosoft\IML

Step 7

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