TROJ_MEDEAR.ER

January 30, 2013
 Analysis by: Nikko Tamana
 ALIASES:

Trojan:Win32/Medear.A(Microsoft)

 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:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware

This Trojan may be dropped by other malware.

It does not have any backdoor routine.

It executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

It does not have any information-stealing capability.

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

  TECHNICAL DETAILS

File Size:

392,192 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

26 Jan 2013

Payload:

Drops files, Connects to URLs/IPs, Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

  • TROJ_MDROPPR.CL

Installation

This Trojan drops the following copies of itself into the affected system and executes them:

  • %Program Files%\Common Files\vmtray.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

It drops the following file(s)/component(s):

    Autostart Technique

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

    HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\
    Windows\CurrentVersion\Run
    VMtray = "%Program Files%\Common Files\vmtray.exe"

    Backdoor Routine

    This Trojan does not have any backdoor routine.

    Download Routine

    This Trojan accesses the following websites to download files:

    • http://{BLOCKED}2.{BLOCKED}9.237.160/news/readme.txt

    It saves the files it downloads using the following names:

    • %Program Files%\Common Files\ODBC\readme.txt
    • %Program Files%\Common Files\ODBC\ctfmon.exe

    (Note: %Program Files% is the default Program Files folder, usually C:\Program Files in Windows 2000, Server 2003, and XP (32-bit), Vista (32-bit), and 7 (32-bit), or C:\Program Files (x86) in Windows XP (64-bit), Vista (64-bit), and 7 (64-bit).)

    It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

    Information Theft

    This Trojan does not have any information-stealing capability.

    Other Details

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

    NOTES:

    It does not have rootkit capabilities.

    It does not exploit any vulnerability.

      SOLUTION

    Minimum Scan Engine:

    9.300

    FIRST VSAPI PATTERN FILE:

    9.682.06

    FIRST VSAPI PATTERN DATE:

    26 Jan 2013

    VSAPI OPR PATTERN File:

    9.683.00

    VSAPI OPR PATTERN Date:

    27 Jan 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

    Remove the malware/grayware file that dropped/downloaded TROJ_MEDEAR.ER

    Step 3

    Restart in Safe Mode

    [ Learn More ]

    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
      • VMtray = "%Program Files%\Common Files\vmtray.exe"

    Step 5

    Search and delete these files

    [ 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.
    • %Program Files%\Common Files\ODBC\readme.txt
    • %Program Files%\Common Files\ODBC\ctfmon.exe

    Step 6

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