Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

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

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

It gathers information and reports it to its servers.

  TECHNICAL DETAILS

File Size: 2408448 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 01 Dec 2015
Payload: Downloads files, Steals information

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.

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

Download Routine

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

  • http://www.{BLOCKED}a-fazendacnpj.info/01-12-2015/Mseserver.html
  • http://www.{BLOCKED}a-fazendacnpj.info/01-12-2015/odserver.iso

It saves the files it downloads using the following names:

  • %Application Data%\Mseserver.html
  • %Application Data%\Mseserver.exe
  • %Application Data%\odserver.iso
  • %Application Data%\odserver.dll

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

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

Other Details

This Trojan gathers the following information and reports it to its servers:

  • computer name
  • os version
  • version
  • OS bit version
  • Mac Address

NOTES:

It reports its infection to the following site:

  • http://www.{BLOCKED}zenda.info/Contador001/write/?query=

  SOLUTION

Minimum Scan Engine: 9.800

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

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.  
  • %Application Data%\Mseserver.html
  • %Application Data%\Mseserver.exe
  • %Application Data%\odserver.iso
  • %Application Data%\odserver.dll

Step 3

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