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VBS_DLOADER.AUSYOR

October 18, 2017
 Analysis by: Byron Jon Gelera
 ALIASES:

VBS/Kryptik.AP trojan (ESET-NOD32)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

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 executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system. As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

16,516 bytes

File Type:

VBS

Memory Resident:

No

Initial Samples Received Date:

06 Jan 2017

Payload:

Connects to URLs/IPs, Downloads files

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 connects to the following website(s) to download and execute a malicious file:

  • http://www.{BLOCKED}o.jp/sweet/tem0613.dat
  • http://www.{BLOCKED}o.jp/sweet/index1.html

It saves the files it downloads using the following names:

  • {Malware Path}\soth.dat
  • {Malware Path}\tofutsu.dat
  • {Malware Path}\wingr.vbe

It then executes the downloaded files. As a result, malicious routines of the downloaded files are exhibited on the affected system.

As of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

13.148.00

FIRST VSAPI PATTERN DATE:

10 Jan 2017

VSAPI OPR PATTERN File:

13.149.00

VSAPI OPR PATTERN Date:

11 Jan 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

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.
  • {Malware Path}\soth.dat
  • {Malware Path}\tofutsu.dat
  • {Malware Path}\wingr.vbe

Step 4

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