Analysis by: Cris Nowell Pantanilla
ALIASES:

Trojan-Downloader.HTML.Agent.aia (Kaspersky), VBS/Downloader.ev (McAfee)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel: Dropped by other malware

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

It executes the dropped file(s). As a result, malicious routines of the dropped files are exhibited on the affected system.

  TECHNICAL DETAILS

File Size: 21,934 bytes
File Type: HTA
Memory Resident: No
Initial Samples Received Date: 22 Apr 2017
Payload: Drops files

Arrival Details

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

  • http://{BLOCKED}nscar.in/test4.hta
  • http://{BLOCKED}.{BLOCKED}.67.42/test5.hta

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

Dropping Routine

This Trojan drops the following files:

  • %User Temp%\1.vbs ← used to send Enter key to MS Word
  • %User Temp%\0011.ps1 ← detected as TROJ_HELMINTH.PS

It executes the dropped file. As a result, malicious routines of the dropped file are exhibited on the affected system.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 13.356.04
FIRST VSAPI PATTERN DATE: 22 Apr 2017
VSAPI OPR PATTERN File: 13.357.00
VSAPI OPR PATTERN Date: 23 Apr 2017
OPP PATTERN File:

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

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

Step 3

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 Temp%\1.vbs
%User Temp%\0011.ps1

Step 4

Scan your computer with your Trend Micro product to delete files detected as HTML_OBFUSCA.SA. 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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