TROJ_DLOAD.TEYJK

October 15, 2015
 Analysis by: Anthony Joe Melgarejo
 ALIASES:

Win32/TrojanDownloader.Agent.BTA (ESET)

 PLATFORM:

Windows

 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.

  TECHNICAL DETAILS

File Size:

167,424 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

04 Oct 2015

Payload:

Connects to URLs/IPs

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 connects to the following website(s) to download and execute a malicious file:

  • http://d1.{BLOCKED}estinfo.com/ct15.zip

It saves the files it downloads using the following names:

  • %User Temp%\{installation date - yyyymmdd}\ct.zip
  • %User Temp%\{installation date - yyyymmdd}\ct.exe (extracted from zip Archive) - detected as TROJ_DOWNCLICK.DCD

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.)

NOTES:
It doesn't perform its intended routine when the following service is found:

  • windowsmanagementservice

  SOLUTION

Minimum Scan Engine:

9.750

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_DLOAD.TEYJK. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • TROJ_DOWNCLICK.DCD

Step 3

Scan your computer with your Trend Micro product to delete files detected as TROJ_DLOAD.TEYJK. 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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