TROJ_DLOADR.BWM

December 09, 2013
 Analysis by: Nikko Tamana
 ALIASES:

Troj/DwnLdr-LDY (Sophos)

 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: Trojan

  • Destructiveness: No

  • Encrypted: Yes

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

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

  TECHNICAL DETAILS

File Size:

65,536 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

05 Dec 2013

Payload:

Downloads files

Arrival Details

This Trojan arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Download Routine

This Trojan downloads the file from the following URL and renames the file when stored in the affected system:

  • http://{BLOCKED}chingsolution.com/images/tere2611.exe
  • http://{BLOCKED}oaching.com/wp-content/uploads/2013/01/tere2611.exe
  • http://{BLOCKED}nclasses.org/images/tere2611.exe
  • http://{BLOCKED}nvithani.com/images/tere2611.exe

It saves the files it downloads using the following names:

  • %User Temp%\{random file name}.exe - Detected as TSPY_ZBOT.YNI
  • %Temporary Internet Files%\Content.IE5\{random folder name}\tere2611[1].exe - Detected as TSPY_ZBOT.YNI

(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, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.. %Temporary Internet Files% is the Temporary Internet Files folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista and 7.)

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

  SOLUTION

Minimum Scan Engine:

9.700

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 malware/grayware files dropped/downloaded by TROJ_DLOADR.BWM

    • TSPY_ZBOT.YNI

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOADR.BWM. 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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