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TROJ_DLOADR.YMJ

August 07, 2015
 Analysis by: Pearl Charlaine Espejo
 ALIASES:

TrojanDownloader:Win32/Inexsmar.A (Microsoft); RDN/Generic Downloader.x (McAfee); Trojan.Win32.Agent.duiavp (NANO-Antivirus); Win32:Malware-gen (Avast)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Downloaded from the Internet, Dropped by other malware


This Trojan may be dropped by other malware.

As of this writing, the said sites are inaccessible.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size:

692,224 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

03 Aug 2015

Payload:

Downloads files

Arrival Details

This Trojan may be dropped by the following malware:

  • JS_FEEBS.GEO

Installation

This Trojan drops the following files:

  • %User Temp%\log{random characters}.tmp.bat - this will delete the executed file

(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.)

Download Routine

This Trojan accesses the following websites to download files:

  • http://photo.{BLOCKED}rary.org/wnctprx

It saves the files it downloads using the following names:

  • %User Temp%\log{random characters}.tmp

(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.)

As of this writing, the said sites are inaccessible.

Other Details

This Trojan deletes itself after execution.

  SOLUTION

Minimum Scan Engine:

9.750

FIRST VSAPI PATTERN FILE:

11.792.08

FIRST VSAPI PATTERN DATE:

15 Jul 2015

VSAPI OPR PATTERN File:

11.793.00

VSAPI OPR PATTERN Date:

16 Jul 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove the malware/grayware file that dropped/downloaded TROJ_DLOADR.YMJ. (Note: Please skip this step if the threat(s) listed below have already been removed.)

    JS_FEEBS.GEO

Step 4

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.
  • %User Temp%\log{random characters}.tmp.bat
  • %User Temp%\log{random characters}.tmp

Step 5

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

Step 6

Remove the malware/grayware file dropped/downloaded by TROJ_DLOADR.YMJ. (Note: Please skip this step if the threat(s) listed below have already been removed.)


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