Worm.MSIL.XWORM.YXEBVZ

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.

It executes commands from a remote malicious user, effectively compromising the affected system. It connects to a website to send and receive information.

It logs a user's keystrokes to steal information.

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:

• %Application Data%\msedge.exe → with HIDDEN and SYSTEM attributes

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following processes:

• powershell.exe -ExecutionPolicy Bypass Add-MpPreference -ExclusionPath '{Malware Path}\{Malware Filename}'
• powershell.exe -ExecutionPolicy Bypass Add-MpPreference -ExclusionProcess '{Malware Filename}'
• powershell.exe -ExecutionPolicy Bypass Add-MpPreference -ExclusionPath '%Application Data%\msedge.exe'
• powershell.exe -ExecutionPolicy Bypass Add-MpPreference -ExclusionProcess 'msedge.exe'

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

• oXwnhd5ZIRDDutbH

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
msedge = %Application Data%\msedge.exe

Other System Modifications

This Worm modifies the following registry key(s)/entry(ies) as part of its installation routine:

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

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

Propagation

This Worm drops the following copy(ies) of itself in all removable drives:

• {Drive Letter}:\DriverInstaller.exe

Backdoor Routine

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

• pong - Sends a "pong" string to the C2
• rec - Restarts the application
• CLOSE - Closes the application
• uninstall - Executes the uninstall commands
• update - Executes the uninstall commands and the updated binary
• DW - Executes a powershell script
• FM - Executes a command from the C2 in memory
• LN - Downloads a file from a URL and execute it.
• Urlopen - Opens a URL through a browser
• Urlhide - Creates a HTTP GET request
• PCShutdown - Executes a shutdown command
• PCRestart - Executes a restart command
• PCLogoff - Executes a logoff command
• RunShell - Executes a command
• StartDDos - Initiates DDoS activities
• StopDDos - Terminates DDoS activities
• StartReport - Sends a list of running processes
• StopReport - Terminates sending of running proccesses list
• Xchat - Sends a "Xchat" string and the ID generated using system information
• Hosts - Sends the drivers\etc\host file contents
• Shosts - Modifies the contents of a file
• DDos - Sends a "DDos" string to the C2
• ngrok - Sends an "ngrok" string and the ID generated using system information
• plugin - Decompresses and executes a plugin
• savePlugin - Saves the decoded plugin to a registry then decompresses and executes it
• RemovePlugins - Deletes the registry with plugin data
• OfflineGet - Sends the contents of the keylogger file
• $cap - Sends a screen capture

It connects to the following websites to send and receive information:

• using TCP:
  • {BLOCKED}dns.org:1111

It connects to the following URL(s) to send and receive commands from a remote malicious user:

• using TCP:
  • {BLOCKED}dns.org:1111

Dropping Routine

This Worm drops the following file(s), which it uses for its keylogging routine:

• %User Temp%\Log.tmp

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Information Theft

This Worm gathers the following data:

• Username
• OS version and architecture
• Malware Variant ID
• File Creation date
• If executed from a removable drive
• If executed with admin rights
• Webcam availability
• CPU Information
• GPU Information
• RAM Information
• Antivirus Product name

It logs a user's keystrokes to steal information.

Other Details

This Worm does the following:

• It sets the attributes of files found in the Removable Drives to HIDDEN and SYSTEM
• It creates a shortcut for each of the file found in the removable drive, with the following details:
  • Shortcut filename: {Original Filename and Extension}.LNK
  • Target Path: cmd.exe /c start DriverInstaller.exe&start {Original Filename & extension} & exit