Analysis by: Wilbert Vidal

ALIASES:

TrojanDownloader:JS/Nemucod!rfn (Microsoft); JS.DownLoader.4270 (DrWeb)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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 accesses websites to download files. This action allows this malware to possibly add other malware on the affected computer. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 13,663 bytes
File Type: Java
Initial Samples Received Date: 05 Oct 2017

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 accesses websites to download the following files:

  • http://{BLOCKED}-eger.de/uyitfu65uy??iOYrjzMvCkN=iOYrjzMvCkN

It saves the files it downloads using the following names:

  • %User Temp%\iOYrjzMvCkN2.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.)

As of this writing, the said sites are inaccessible.