BKDR_MIDHOS.DMS

 Analysis by: Christopher Daniel So

 ALIASES:

Trojan.Win32.Midhos.fuy (Kaspersky)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This backdoor may be dropped by other malware.

It runs certain commands that it receives remotely from a malicious user. Doing this puts the affected computer and information found on the computer at greater risk.

It deletes the initially executed copy of itself.

  TECHNICAL DETAILS

File Size:

Varies

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

03 Jul 2012

Payload:

Connects to URLs/IPs

Arrival Details

This backdoor may be dropped by the following malware:

  • TROJ_ARTIEF.ADQ
  • TROJ_ARTIEF.DMX

Installation

This backdoor drops the following copies of itself into the affected system:

  • %User Temp%\conime.exe

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It drops the following files:

  • %User Temp%\conime.dll - also detected by Trend Micro as BKDR_MIDHOS.DMS
  • %User Temp%\conime.inf

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003.)

It terminates the execution of the copy it initially executed and executes the copy it drops instead.

Autostart Technique

This backdoor drops the following file(s) in the Windows User Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\Updata.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.)

Backdoor Routine

This backdoor executes the following command(s) from a remote malicious user:

  • Get drive space information
  • List the contents of a directory
  • Delete a file
  • Download a file from the C&C server
  • Upload a file to the C&C server
  • Create a process
  • Enumerate processes
  • Terminate a process
  • Start a remote command prompt
  • Run a command and send the results
  • Take a screenshot
  • Update configuration file
  • Uninstall itself
  • Set current directory

Other Details

This backdoor deletes the initially executed copy of itself

NOTES:

This backdoor sets the attributes of the following folder to Hidden:

  • %User Startup%

It checks if the following registry entry is present on the affected system:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run 360Safetray

If it does not exist, it starts a hidden instance of Internet Explorer which loads the component CONIME.DLL automatically. If it exists, it calls the component CONIME.DLL directly.

The said DLL component contains the backdoor routines of this malware. The configuration file CONIME.INF contains the address of the C&C server and the port it uses to connect. The default contents of the configuration file points to the C&C server {BLOCKED}.{BLOCKED}.77.98:1080.

  SOLUTION

Minimum Scan Engine:

9.200

FIRST VSAPI PATTERN FILE:

9.232.07

FIRST VSAPI PATTERN DATE:

04 Jul 2012

VSAPI OPR PATTERN File:

9.233.00

VSAPI OPR PATTERN Date:

04 Jul 2012

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

Remove the malware/grayware file that dropped/downloaded BKDR_MIDHOS.DMS

Step 3

Identify and terminate files detected as BKDR_MIDHOS.DMS

[ Learn More ]
  1. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  2. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Terminate a malware/grayware process

[ Learn More ]

*Note: If the detected process is not displayed in theWindows Task Manager, continue doing the next steps.

    • IEXPLORE.EXE

Step 5

  1. Open a command prompt.
    • For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Open input box, type CMD then press Enter.
  2. In the CMD console, type the following:

    ATTRIB [+R | -R] [+A | -A ] [+S | -S] [+H | -H] [+I | -I] [drive:][path][file name] [/S [/D] [/L]]

    Where:
    + Sets an attribute.
    - Clears an attribute
    R Read-only file attribute
    A Archive file attribute
    S System file attribute
    H Hidden file attribute
    I Not content indexed file attribute
    [drive:][path][filename]
    Specifies a file or files for attrib to process
    /S Processes matching files in the current folder and all subfolders.
    /D Processes folders
    /L Work on the attributes of the Symbolic Link versus the target of the Symbolic Link
    Example:
    To unhide all files and folders (including subfolders) in drive D:
    ATTRIB –H D:\* /S /D
  3. Repeat Step 2 for folders and files in other drives or directories.

Step 6

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.
  • %User Startup%\Updata.lnk
  • %User Temp%\conime.inf

Step 7

Scan your computer with your Trend Micro product to delete files detected as BKDR_MIDHOS.DMS. 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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