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JS_NEMUCOD.ELDSAUGH

June 22, 2017
 Analysis by: John Kevin Sanchez
 ALIASES:

Trojan.JS.Agent.dxz (Kaspersky), JS/Nemucod.7AE6!tr (Fortinet), Trojan-Downloader.JS.Nemucod (Ikarus)

 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


This Trojan may be downloaded from remote sites by other malware.

It connects to certain websites to send and receive information.

  TECHNICAL DETAILS

File Size:

335,271 bytes

File Type:

JS

Memory Resident:

Yes

Initial Samples Received Date:

01 Jun 2017

Payload:

Drops files, Connects to URLs/IPs, Executes files

Arrival Details

This Trojan may be downloaded from remote site(s) by the following malware:

Installation

This Trojan drops the following copies of itself into the affected system:

  • %User Startup%\seter64.jse

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

It drops the following files:

  • %User Temp%\saymyname.txt

(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 saves the files it downloads using the following names:

  • %User Temp%\floor{random}.exe - detected as TROJ_OTLARD.TY
  • %User Temp%\floor{random}.gop

Other Details

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

  • https://{BLOCKED}.{BLOCKED}.82.38:45000/C/pollos.php?add=e9e45de07d328e8d46adf4357840be5e&floor{random}&uid={value}&out={process id of executed downloaded file}&ver={version number}

It displays the following message boxes:



It does the following:

  • Enumerates running processes
  • Gets OS version
  • Send running processes and OS to C&C
  • Checks for these running processes:
    Procmon
    Wireshark
    Tempiexplore.exe
    ProcessHacker
    vmtoolsd
    VBoxService
    python
    Proxifier.exe
    Johnson-PC
    ImmunityDebugger.exe
    lordPE.exe
    ctfmon.exe
    *JOHN-PC
    BehaviorDumper
    anti-virus.EXE
    AgentSimulator.exe
    VzService.exe
    VmRemoteGuest
  • Malware creates %User Temp%\saymyname.txt when it cannot download %User Temp%\floor{random}.exe. %User Temp%\saymyname.txt contains list of files from removable and network drives with the following extensions:
    .doc
    .xls
    .pdf
    .rtf
    .txt
    .pub
    .odt
    .ods
    .odp
    .odm
    .odc
    .odb
    .wps
    .xlk
    .ppt
    .mdb
    .accdb
    .pst
    .dwg
    .dxf
    .dxg
    .wpd
    .rtf
    .wb2
    .mdf
    .dbf
    .psd
    .pdd
    .eps
    .ai
    .indd
    .cdr
    .img_
    .jpg
    .dng
    .3fr
    .arw
    .srf
    .sr2
    .bay
    .crw
    .cr2
    .dcr
    .kdc
    .erf
    .mef
    .mrw
    .nef
    .nrw
    .orf
    .raf
    .raw
    .rwl
    .rw2
    .r3d
  • Executes %User Temp%\floor{random}.exe and if unsuccessful deletes all .exe, .gop, .txt, .log, .jse in the %User Temp% folder.

(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.)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.444.04

FIRST VSAPI PATTERN DATE:

01 Jun 2017

VSAPI OPR PATTERN File:

13.445.00

VSAPI OPR PATTERN Date:

02 Jun 2017

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

Restart in Safe Mode

[ Learn More ]

Step 4

Search and delete this file

[ 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 Startup%\seter64.jse
  • %User Temp%\floor{random}.exe
  • %User Temp%\floor{random}.gop
  • %User Temp%\saymyname.txt

Step 5

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

Scan your computer with your Trend Micro product to delete files detected as JS_NEMUCOD.ELDSAUGH. 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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