Analysis by: Jennifer Gumban
ALIASES:

TrojanDownloader:JS/Nemucod.AAY (Microsoft), JS:Trojan.Cryxos.648 (Bitdefender)

 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: Via email, Dropped by other malware, Downloaded from the Internet

This Trojan arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users. It 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: 1,535 bytes
File Type: JS
Memory Resident: No
Initial Samples Received Date: 20 Apr 2017
Payload: Connects to URLs/IPs

Arrival Details

This Trojan arrives as an attachment to email messages mass-mailed by other malware/grayware or malicious users.

It 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://{BLOCKED}elijning.be/libraries/joomla/application/web/counter/exe1.exe
  • http://{BLOCKED}elijning.be/libraries/joomla/application/web/counter/exe2.exe
  • http://{BLOCKED}elijning.be/libraries/joomla/application/web/counter/exe3.exe

It saves the files it downloads using the following names:

  • %User Temp%\exe1.exe
  • %User Temp%\exe2.exe
  • %User Temp%\exe3.exe

(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.)

Trend Micro detects the dowloaded file as:

  • RANSOM_CRYPAURA

Other Details

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

  • http://sklep.{BLOCKED}l.com.pl/administrator/components/com_jce/views/cpanel/counter/?{values}
  • http://{BLOCKED}eriak.com/images/joomgallery/thumbnails/ass_-_popsi_6/counter/?{values}
  • http://{BLOCKED}otelgrenoble.com/old/wp-content/themes/booster/counter/?{values}
  • http://{BLOCKED}edal.hu/administrator/components/com_finder/tables/counter/?{values}
  • http://{BLOCKED}ejrah.com/administrator/templates/system/images/counter/?{values}

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.354.02
FIRST VSAPI PATTERN DATE: 20 Apr 2017
VSAPI OPR PATTERN File: 13.355.00
VSAPI OPR PATTERN Date: 21 Apr 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 normal mode and scan your computer with your Trend Micro product for files detected as JS_NEMUCOD.F017DL. 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 4

Remove malware/grayware files dropped/downloaded by JS_NEMUCOD.F017DL. (Note: Please skip this step if the threats listed below have already been removed.)

     
    • RANSOM_CRYPAURA

Step 5

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%\exe1.exe
  • %User Temp%\exe2.exe
  • %User Temp%\exe3.exe

Step 6

Restart in Safe Mode

[ Learn More ]


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