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BKDR_MORIX.YU

October 10, 2013
 Analysis by: Jimelle Monteser
 ALIASES:

Backdoor:Win32/Morix.B (Microsoft), Backdoor.Win32.Morix.b (v) (Sunbelt), Backdoor.Win32.Morix (Ikarus)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

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 uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It executes commands from a remote malicious user, effectively compromising the affected system.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

81,920 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Aug 2013

Payload:

Compromises system security

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 drops the following copies of itself into the affected system:

  • %Windows%\44E03918\svchsot.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It uses Windows Task Scheduler to create a scheduled task that executes the dropped copy.

It creates the following folders:

  • %Windows%\44E03918

(Note: %Windows% is the Windows folder, which is usually C:\Windows.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • 115.239.231.60:2012127.0.0.1:2012127.0.0.1:2012

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
44E03918 = "%Windows%\44E03918\svchsot.exe"

The scheduled task executes the malware every:

  • 1 hour

Other System Modifications

This backdoor adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Control\MediaResources\msvideo

HKEY_LOCAL_MACHINE\SYSTEM\InfoTime

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\InfoTime
44E03918 = "{{Year}{Month}{Day}}"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
AtTaskMaxHours = "48"

Backdoor Routine

This backdoor executes the following commands from a remote malicious user:

  • Download files
  • Perform a shell command
  • Manage services
  • Manage processes
  • Manage windows
  • Capture screenshots

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • http://{BLOCKED}.{BLOCKED}.231.60:2012

Process Termination

This backdoor terminates the following processes if found running in the affected system's memory:

  • KsafeTray.exe

Dropping Routine

This backdoor drops the following files:

  • %Windows%\Tasks\At{number}.job - 1 to 24
  • %System%\44E03918.key

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

Information Theft

This backdoor gathers the following data:

  • OS Version
  • Host Name
  • Socket Information
  • System Information (Lan IP, Wan IP, Computer name, Username, Account Type, OS)
  • Driver Description
  • Hard Drive Information (Volume Information, Free Space, File Information)

Other Details

This backdoor deletes the initially executed copy of itself

  SOLUTION

Minimum Scan Engine:

9.300

FIRST VSAPI PATTERN FILE:

10.206.04

FIRST VSAPI PATTERN DATE:

09 Aug 2013

VSAPI OPR PATTERN File:

10.207.00

VSAPI OPR PATTERN Date:

10 Aug 2013

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_LOCAL_MACHINE\SYSTEM
    • InfoTime
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
    • MediaResources

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\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • 44E03918 = "%Windows%\44E03918\svchsot.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours = "48"

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.
  • %Windows%\44E03918\

Step 6

Search and delete this file

[ Learn More ]
There may be some 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.
  • %Windows%\Tasks\At{number}.job - 1 to 24
  • %System%\44E03918.key

Step 7

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