WORM_ZLADER.B

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 modifies the Internet Explorer Zone Settings.

It connects to certain websites to send and receive information. It deletes itself after execution.

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 files:

• %Application Data%\cabfile.cab
• {Removable Drive Letter}:\{Shortcut files with the filename of every folder in the removable drive}
  • The malware creates these shortcut files in order to trick the user due to its folder icon and legit filenames.
  • The target path of these shortcuts is set to: %System%\cmd.exe /C ""$RECYCLE.BIN.{GUID}\{GUID}.cmd" && explorer "{GUID folder name - where the original files are stored}""

(Note: %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.)

It drops the following non-malicious file:

• %Application Data%\dpx.dll -> serves as a component file used by the malware

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

It injects itself into the following processes as part of its memory residency routine:

• explorer.exe

Propagation

This worm creates the following folders in all removable drives:

• {Removable Drive Letter}:\$RECYCLE.BIN.{GUID} -> set attributes to Hidden

It drops copies of itself in the following drives:

• {Removable Drive Letter}:\$RECYCLE.BIN.{GUID}\{GUID}.{src/pif/cmd} -> Set attribute to Hidden and would look like a shortcut file.

Web Browser Home Page and Search Page Modification

This worm modifies the Internet Explorer Zone Settings.

Other Details

This worm connects to the following website to send and receive information:

• http://{BLOCKED}ndidnted.com/h/gate.php

It does the following:

• It renames all the original folders in Removable Drives to: {Removable Drive Letter}:\{random GUIDs}
  • Attributes of these folders are set to Hidden
• It stops and disables the following windows components by using the following commands:
  • cmd.exe /c net stop SharedAccess
  • cmd.exe /c sc config SharedAccess start=disabled
  • cmd.exe /c net stop wscsvc
  • cmd.exe /c sc config wscsvc start=disabled
  • cmd.exe /c net stop wuauserv
  cmd.exe /c sc config wuauserv start=disabled
• It creates .LNK (shortcut) files using folder names found in removable drives. It then hides the original folders tricking users to click .LNK files. This .LNK files point out to a dropped copy of itself in the removable drive.

It deletes itself after execution.