BKDR_MORIX.DUKKT

August 15, 2014
 Analysis by: Adrian Cofreros
 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:

  • 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.

  TECHNICAL DETAILS

File Size:

208,896 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

13 Aug 2014

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%\5C1B5602\svchsot.exe

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

It creates the following folders:

  • %Windows%\5C1B5602

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

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
5C1B5602 = "%Windows%\5C1B5602\svchsot.exe"

Other System Modifications

This backdoor adds the following registry entries:

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

It modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Schedule
NextAtJobId = "19"

(Note: The default value data of the said registry entry is "1".)

Dropping Routine

This backdoor drops the following files:

  • %Windows%\Task\At1.job
  • %Windows%\Task\At2.job
  • %Windows%\Task\At3.job
  • %Windows%\Task\At4.job
  • %Windows%\Task\At5.job
  • %Windows%\Task\At6.job
  • %Windows%\Task\At7.job
  • %Windows%\Task\At8.job
  • %Windows%\Task\At9.job
  • %Windows%\Task\At10.job
  • %Windows%\Task\At11.job
  • %Windows%\Task\At12.job
  • %Windows%\Task\At13.job
  • %Windows%\Task\At14.job
  • %Windows%\Task\At15.job
  • %Windows%\Task\At16.job
  • %Windows%\Task\At17.job
  • %Windows%\Task\At18.job
  • %Windows%\Task\At19.job
  • %Windows%\Task\At20.job
  • %Windows%\Task\At21.job
  • %Windows%\Task\At22.job
  • %Windows%\Task\At23.job
  • %Windows%\Task\At24.job

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

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}5876783.f3322.org

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.982.05

FIRST VSAPI PATTERN DATE:

13 Aug 2014

VSAPI OPR PATTERN File:

10.983.00

VSAPI OPR PATTERN Date:

14 Aug 2014

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 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
    • 5C1B5602 = "%Windows%\5C1B5602\svchsot.exe"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • AtTaskMaxHours = "48"

Step 4

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator’s help. You may also check out this Microsoft article first before modifying your computer's registry.

 
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Schedule
    • From: NextAtJobId = "19"
      To: NextAtJobId = "1"

Step 5

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.
  • %Windows%\5C1B5602

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%\Task\At1.job
  • %Windows%\Task\At2.job
  • %Windows%\Task\At3.job
  • %Windows%\Task\At4.job
  • %Windows%\Task\At5.job
  • %Windows%\Task\At6.job
  • %Windows%\Task\At7.job
  • %Windows%\Task\At8.job
  • %Windows%\Task\At9.job
  • %Windows%\Task\At10.job
  • %Windows%\Task\At11.job
  • %Windows%\Task\At12.job
  • %Windows%\Task\At13.job
  • %Windows%\Task\At14.job
  • %Windows%\Task\At15.job
  • %Windows%\Task\At16.job
  • %Windows%\Task\At17.job
  • %Windows%\Task\At18.job
  • %Windows%\Task\At19.job
  • %Windows%\Task\At20.job
  • %Windows%\Task\At21.job
  • %Windows%\Task\At22.job
  • %Windows%\Task\At23.job
  • %Windows%\Task\At24.job

Step 7

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