BKDR_MORIX.A

 Analysis by: Christopher Daniel So

 ALIASES:

Backdoor:Win32/Morix.B (Microsoft), Backdoor.Win32.Agent.bici (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

This backdoor may arrive bundled with malware packages as a malware component. It may be dropped by other malware. It may be unknowingly downloaded by a user while visiting malicious websites.

It connects to a website to send and receive information. However, as of this writing, the said sites are inaccessible.

It gathers certain information on the affected computer.

  TECHNICAL DETAILS

File Size:

22,175,066 bytes

File Type:

DLL

Memory Resident:

Yes

Initial Samples Received Date:

19 Jul 2011

Payload:

Modifies system registry, Connects to URLs/IPs

Arrival Details

This backdoor may arrive bundled with malware packages as a malware component.

It may be dropped by other malware.

It may be unknowingly downloaded by a user while visiting malicious websites.

Autostart Technique

This backdoor modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AppMgmt\Parameters
ServiceDll = "C:\Progra~1\%Program Files%\Wdcp.dll"

(Note: The default value data of the said registry entry is %SystemRoot%\System32\appmgmts.dll.)

Other System Modifications

This backdoor modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AppMgmt
Start = 2

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\AppMgmt
Type = 120

(Note: The default value data of the said registry entry is 20.)

Backdoor Routine

This backdoor connects to the following websites to send and receive information:

  • {BLOCKED}123.3322.org:8080

However, as of this writing, the said sites are inaccessible.

Information Theft

This backdoor gathers the following information on the affected computer:

  • Computer name
  • Processor speed (in MHz)
  • Operating system version
  • Number of processors
  • Number of days since the system startup
  • Hard disk geometry
  • Total amount of memory (in MB)

NOTES:
It checks the following anti-malware related processes and adds them to the gathered information:

  • 360tray.exe
  • avp.exe
  • KvMonXP.exe
  • RavMonD.exe
  • 360sd.exe
  • Mcshield.exe
  • egui.exe
  • kxetray.exe
  • knsdtray.exe
  • TMBMSRV.exe
  • avcenter.exe
  • ashDisp.exe
It checks the following processes and adds them to the gathered information:
  • my.exe
  • dp.exe
  • mdm365.exe
  • dnf.exe
  • xy2.exe
  • xy3.exe
  • QQhxgame.exe
  • wow.exe
  • tw2.exe

It has keylogging capabilities. The logged keystrokes are added to the gathered information.

It sends all the information it gathers to the following remote site at 5:00 to 5:09 UTC and 13:00 to 13:09 UTC:

  • {BLOCKED}h.{BLOCKED}p.net:80

However, as of this writing, the said site is inaccessible.

It terminates the process 360tray.exe if the operating system is Windows XP and the process logonui.exe is running.

It deletes itself if the process DSMain.exe is running.

It creates the following registry entries to enable automatic execution of its malware component, 362.VBS, detected by Trend Micro as VBS_ARUN.ASM, at every system startup if the operating system is Windows 2000:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
{random string}="file:c:\windows\362.VBS"

It adds the following registry entries to enable its automatic execution at every system startup if the operating system is not Windows 2000:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
{random string}="rundll32.exe C:\Progra~1\%%Progr~1\Wdcp.dll main"

It downloads the file from http://www.{BLOCKED}011.com/OOO.eXe if the process my.exe is executing and saves it to {malware path}\crss.exe. It then executes the downloaded file. However, as of this writing, the said site is inaccessible.

It downloads the file from the URL specified in the registry value DN in the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Winsock. It saves the downloaded file as {malware path}\CTFM0N.EXE, then executes it.

It monitors its malware file at %Program Files%\Wdcp.dll. If the malware file %Program Files%\Wdcp.dll is deleted, it drops a new copy of it.

The malware contains errors in its code. This causes the malware not to perform some of its routines.

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.298.12

FIRST VSAPI PATTERN DATE:

19 Jul 2011

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

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
    • {random string}="file:c:\windows\362.VBS"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • {random string}="rundll32.exe C:\Progra~1\%%Progr~1\Wdcp.dll main"

Step 4

Restore this modified 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\CurrentControlSet\Services\AppMgmt\Parameters
    • From: ServiceDll="C:\Progra~1\%Program Files%\Wdcp.dll"
      To: ServiceDll="%SystemRoot%\System32\appmgmts.dll"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AppMgmt
    • From: Start=2
      To: Start=3
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\AppMgmt
    • From: Type=120
      To: Type=20

Step 5

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.
{malware path}\crss.exe
{malware path}\CTFM0N.EXE

Step 6

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


Did this description help? Tell us how we did.