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Worm.Win32.DAHAD.JKA

November 14, 2019
 Modified by: Jay Garcia
 ALIASES:

TrojanSpy:Win32/VB (Microsoft); Trojan-FFIH!684B6EE7DA87 (McAfee); Trojan.Gen.6 (Symantec); Worm.Win32.VB.fmu (Kaspersky); W32/VB-HZG (Sophos); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Worm 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:

393,216 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

12 Nov 2019

Arrival Details

This Worm 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 Worm drops the following copies of itself into the affected system:

  • %System%\flash.exe
  • {Removable Drive}\{folder name}.exe

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It adds the following processes:

  • explorer.exe {malware path}\{malware name}
  • cmd.exe /c REG ADD HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run /v microsoftflash /t REG_EXPAND_SZ /d %SystemRoot%\system32\flash.exe /f
  • %System%\reg.exe REG ADD HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run /v microsoftflash /t REG_EXPAND_SZ /d %System%\flash.exe /f

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

Autostart Technique

This Worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
microsoftflash = %System%\flash.exe

Other Details

This Worm does the following:

  • It drops copies of itself in removable drive using the names of the folders located on the said drives as filenames. It then hides the original folders to trick users on opening the files.

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

15.474.08

FIRST VSAPI PATTERN DATE:

04 Nov 2019

VSAPI OPR PATTERN File:

15.475.00

VSAPI OPR PATTERN Date:

05 Nov 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 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

Restart in Safe Mode

[ Learn More ]

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run
    • microsoftflash = %System%\flash.exe

Step 5

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.  
  • %System%\flash.exe
  • {Removable Drive}\{folder name}.exe

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as Worm.Win32.DAHAD.JKA. 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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