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VBS_DLOADR.YYSWY

September 07, 2018
 Analysis by: Michael Jhon Ofiaza
 ALIASES:

TrojanDownloader:HTML/Adodb.gen!A [generic] (Microsoft) ; Trojan.Downloader.VBS.JY (Bitdefender)

 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted: No

  • 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.

However, as of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size:

4,332 bytes

File Type:

VBS

Memory Resident:

No

Initial Samples Received Date:

01 Jun 2018

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 adds the following processes:

  • C:\Users\Public\Documents\fix.exe - Windows 2000 Professional and above
  • c:\Docume~1\AllUse~1\DRM\fix.exe - other versions

Other System Modifications

This Trojan deletes the following files:

  • Windows 2000 Professional and above:
    • C:\Users\Public\Documents\active_desktop_render.dll
    • C:\Users\Public\Documents\soundbox.dll
    • C:\Users\Public\Documents\fix.exe
    • C:\Users\Public\Documents\config.json
    • C:\Users\Public\Documents\y.txt
    • C:\Users\Public\Documents\y.png
    • C:\Users\Public\Documents\active_desktop_render_x64.dll
    • C:\Users\Public\Documents\64f.zip -> 64 bit
    • C:\Users\Public\Documents\32f.zip -> 32 bit
  • other versions:
    • c:\Docume~1\AllUse~1\DRM\active_desktop_render.dll
    • c:\Docume~1\AllUse~1\DRM\soundbox.dll
    • c:\Docume~1\AllUse~1\DRM\fix.exe
    • c:\Docume~1\AllUse~1\DRM\config.json
    • c:\Docume~1\AllUse~1\DRM\y.txt
    • c:\Docume~1\AllUse~1\DRM\y.png
    • c:\Docume~1\AllUse~1\DRM\active_desktop_render_x64.dll
    • c:\Docume~1\AllUse~1\DRM\64f.zip -> 64 bit
    • c:\Docume~1\AllUse~1\DRM\32f.zip -> 32 bit

Process Termination

This Trojan terminates the following processes if found running in the affected system's memory:

  • repair.exe

Download Routine

This Trojan accesses the following websites to download files:

  • http://a.1b{BLOCKED}ae.tk\64f.zip ->64bit
  • http://a.1b{BLOCKED}ae.tk\32f.zip ->32bit

It saves the files it downloads using the following names:

  • C:\Users\Public\Documents\32f.zip -> 32 bit, Windows 2000 Professional and above
  • C:\Users\Public\Documents\64f.zip -> 64 bit, Windows 2000 Professional and above
  • c:\Docume~1\AllUse~1\DRM\32f.zip -> 32 bit, other versions
  • c:\Docume~1\AllUse~1\DRM\64f.zip -> 64 bit, other versions

Other Details

This Trojan does the following:

  • Extracts the downloaded zip file and delete the zip file afterwards

However, as of this writing, the said sites are inaccessible.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.346.05

FIRST VSAPI PATTERN DATE:

28 Jun 2018

VSAPI OPR PATTERN File:

14.347.00

VSAPI OPR PATTERN Date:

29 Jun 2018

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.  
  • C:\Users\Public\Documents\32f.zip
  • C:\Users\Public\Documents\64f.zip
  • c:\Docume~1\AllUse~1\DRM\32f.zip
  • c:\Docume~1\AllUse~1\DRM\64f.zip

Step 4

Scan your computer with your Trend Micro product to delete files detected as VBS_DLOADR.YYSWY. 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 the following Trend Micro Support pages for more information:


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