ALIASES:

Backdoor:Win32/Morix.B (Microsoft); Generic MSVC.c (McAfee); Backdoor.Fosor (Symantec); Trojan.Win32.Generic!BT (Sunbelt); Gen:Variant.Graftor.733 (FSecure)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size: 165,573 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 25 Jan 2012

Arrival Details

This backdoor 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 backdoor creates the following folders:

  • %Program Files%\%Program Files%

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other System Modifications

This backdoor deletes the following files:

  • %System Root%\ntldr.sys

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It deletes the following folders:

  • %System Root%\%Progr~1

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Winsock
ConnectGroup = "Default"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Services\Winsock
MyVerSion = "2012"

Dropping Routine

This backdoor drops the following files:

  • %System Root%\ntldr.SYS
  • %Program Files%\%Program Files%\laass.exe
  • %Program Files%\%Program Files%\Cest.bat
  • %Program Files%\%Program Files%\~
  • %Program Files%\%Program Files%\922.URL
  • %Program Files%\%Program Files%\Dest.BAt
  • %Program Files%\%Program Files%\923.URL

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %Program Files% is the default Program Files folder, usually C:\Program Files.)

Other Details

This backdoor deletes the initially executed copy of itself

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

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\Winsock
    • ConnectGroup="Default"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\Winsock
    • MyVerSion="2012"

Step 3

Search and delete these files

[ 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 Root%\ntldr.SYS
  • %Program Files%\%Program Files%\laass.exe
  • %Program Files%\%Program Files%\Cest.bat
  • %Program Files%\%Program Files%\~
  • %Program Files%\%Program Files%\922.URL
  • %Program Files%\%Program Files%\Dest.BAt
  • %Program Files%\%Program Files%\923.URL

Step 4

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. %Program Files%\%Program Files%

Step 5

Scan your computer with your Trend Micro product to delete files detected as BKDR_MORIX.JWE. 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.

Step 6

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again. %System Root%\ntldr.sys


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