Analysis by: Adrian Cofreros
ALIASES:

TrojanDownloader:Win32/Streamto.A(Microsoft),VBS/TrojanDownloader.Small.L trojan(NOD32),Trojan-Downloader.VBS.Small.l(Kaspersky)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

 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.

  TECHNICAL DETAILS

File Size: Varies
File Type: VBS
Memory Resident: No
Initial Samples Received Date: 12 Oct 2012

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.

Installation

This Trojan drops and executes the following files:

  • {malware path}\dnf2.exe

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://1.{BLOCKED}x.eu/dnf2.exe

  SOLUTION

Minimum Scan Engine: 9.700
FIRST VSAPI PATTERN FILE: 10.790.08
FIRST VSAPI PATTERN DATE: 12 May 2014
VSAPI OPR PATTERN File: 10.791.00
VSAPI OPR PATTERN Date: 13 May 2014

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

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.  
  • {malware path}\dnf2.exe

Step 3

Scan your computer with your Trend Micro product to delete files detected as VBS_DLOADER.HEI. 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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