Analysis by: Francis Xavier Antazo
 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel: Via removable drives

This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

It drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

It executes commands from a remote malicious user, effectively compromising the affected system.

It modifies certain registry entries to hide Hidden files.

  TECHNICAL DETAILS

File Size: 1,392,640 bytes
File Type: EXE
Memory Resident: No
Initial Samples Received Date: 05 Dec 2014
Payload: Connects to URLs/IPs, Steals information, , Compromises system security

Arrival Details

This worm arrives via removable drives.

It 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 and executes them:

  • %System%\flash.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:

  • cmd.exe {to modify and add registries}

It uses the default Windows folder icon to trick users into opening the file. Double-clicking the file executes this malware.

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"

Propagation

This worm drops copies of itself in removable drives. These dropped copies use the names of the folders located on the said drives for their file names.

Backdoor Routine

This worm executes the following commands from a remote malicious user:

  • Terminate itself
  • Get screenshot
  • Upload stolen information
  • Execute programs
  • Download files
  • Enumerate folders
  • Visit a webpage
  • Send stolen information thru email
  • Enumerate drives and determine their drive type (removable, remote, network, cd-rom, etc.)

It posts the following information to its command and control (C&C) server:

  • .net version
  • current activewindow
  • Computer name
  • Operating system version
  • User profile directory
  • User name
  • Processor information

Stolen Information

This worm sends the data it gathers to the following email addresses via SMTP:

  • {BLOCKED}hadad998@yahoo.com

Drop Points

Some of the email addresses that this spyware uses are the following:

  • {BLOCKED}adad200@gmail.com

Other Details

This worm modifies the following registry entries to hide Hidden files:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\Hidden\
SHOWALL
CheckedValue = "0"

(Note: The default value data of the said registry entry is 1.)

  SOLUTION

Minimum Scan Engine: 9.700

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

Identify and terminate files detected as WORM_DAHAD.XVW

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 3

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\Microsoft\Windows\CurrentVersion\Run
    • microsoftflash = "%System%\flash.exe"

Step 4

Restore modified and/or deleted registry value/s using this VBScript

To restore the modified and/or deleted registry value/s:

  1. Open Notepad.
    » For Windows 2000, Windows XP, and Windows Server 2003 users, click Start>Run. In the Open input box, type notepad then press Enter.
    » For Windows Vista, Windows 7 and Windows Server 2008 users, click Start, type notepad in the Search input field then press Enter.
    » For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type notepad, then press Enter.
  2. Copy and paste the following script:
  3. Save this file as C:\RESTORE.VBS.
  4. Run C:\RESTORE.VBS.
    » For Windows 2000, XP, and Server 2003 users, click Start>Run. In the Open input box, type C:\RESTORE.VBS then press Enter.
    » For Windows Vista, Windows 7 and Windows Server 2008 users, click Start, type C:\RESTORE.VBS in the Search input field then press Enter.
    » For Windows 8, Windows 8.1, and Windows Server 2012 users, right-click on the lower left corner of the screen, click Run, type C:\RESTORE.VBS, then press Enter.

Step 5

Scan your computer with your Trend Micro product to delete files detected as WORM_DAHAD.XVW. 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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