TROJ_ZEKOS.B

March 10, 2014
 Analysis by: Mark Joseph Manahan
 ALIASES:

Trojan horse Generic_r.DKQ (AVG) ,W32/Daws.CAKY!tr (Fortinet) ,Trojan-Dropper.Win32.Daws (Ikarus) ,Trojan-Dropper.Win32.Daws.caky (Kaspersky) ,Win32/Viknok.F trojan (Eset) ,Trojan.Adclicker (Symantec) ,Trj/dtcontx.J (Panda) ,Trojan.Win32.Generic!BT (Sunbelt)

 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 connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

121,344 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

29 Jan 2014

Payload:

Connects to URLs/IPs, Drops files, Modifies 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.

Other System Modifications

This Trojan modifies the following file(s):

  • %System%\rpcss.dll - renamed to {random filename}.{random extension} (normal dll)
  • %System%\rpcss.dll - detected as PTCH_ZEKOS.SM
  • %System%\dllcache\rpcss.dl - detected as PTCH_ZEKOS.SM

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://{BLOCKED}-walk.org/load.php?id={no.}&p={no.}&t={no.}&e={no.}
  • http://{BLOCKED}-gamma.net/load.php?id={no.}&p={no.}&t={no.}&e={no.}
  • http://{BLOCKED}to-step1.com/load.php?id={no.}&p={no.}&t={no.}&e={no.}

It saves the files it downloads using the following names:

  • %System%\{random filename}.{random extension} - encrypted code 1
  • %System%\{random filename}.{random extension} - {Generated Hash}

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Information Theft

This Trojan injects itself into the following web browsers to monitor searches made by the user on the following search engines:

  • firefox.exe
  • chrome.exe
  • iexplore.exe
  • safari.exe
  • opera.exe
  • trustedinstaller.exe
  • update.exe

Other Details

This Trojan connects to the following website to send and receive information:

  • http://{BLOCKED}4all.org/gate.php
  • http://{BLOCKED}base.org/gate.php
  • http://{BLOCKED}.{BLOCKED}.139.19/gate.php
  • http://{BLOCKED}.{BLOCKED}.138.89/gate.php

NOTES:

This Trojan monitors the following process:

  • firefox.exe
  • chrome.exe
  • iexplore.exe
  • safari.exe
  • opera.exe
  • trustedinstaller.exe
  • update.exe

It connects to the following URLs as part of its pay-per-click routine to gain monetary value:

  • http://{BLOCKED}n9.info/task/2000/
  • http://{BLOCKED}-n.net/task/2000/
  • http://{BLOCKED}5.info/task/2000/
  • http://{BLOCKED}wx.net/task/2000/
  • http://{BLOCKED}der-k.com/task/2000/
  • http://{BLOCKED}zone.net/task/2000/
  • http://{BLOCKED}oingz.info/task/2000/
  • http://{BLOCKED}lor17.com/task/2000/
  • http://{BLOCKED}-s.biz/task/2000/

  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_ZEKOS.B

    • PTCH_ZEKOS.SM

Step 3

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