Trojan.Win64.DRIDEX.GR

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.

It retrieves specific information from the affected system.

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 drops the following files:

• %Application Data%\{Existing Folder}\{random characters}\{file name}.exe - legitimate Windows executable
• %Application Data%\{Existing Folder}\{random characters}\{executable's dll name}.dll - modified copy of itself

(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 creates the following folders:

• %Application Data%\{Existing Folder}\{random characters}\ - where existing folders can be any folder within the subdirectories of %Application Data%

(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:

• {hash of computer name and user name}

It injects codes into the following process(es):

• explorer.exe

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Olxdkxkrdtg = "%Application Data%\{Existing Folder}\{random characters}\{file name}.exe"

It drops the following file(s) in the Windows Startup folder to enable its automatic execution at every system startup:

• %User Startup%\{random characters}.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows 2003(32-bit), XP and 2000(32-bit), or C:\Users\{user name}\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit), 10(64-bit).)

Information Theft

This Trojan retrieves the following information from the affected system:

• OS Version
• Computer Name
• User Name
• Install Date
• Running Privilege
• UAC Configurations
• Machine GUID
• System Information

Other Details

This Trojan does the following:

• It executes the following command to bypass Windows Firewall:
  netsh advfirewall firewall add rule name="Core Networking - Multicast Listener Done (ICMPv4-In)" program="C:\Windows\Explorer.EXE" dir=in action=allow protocol=TCP localport=any - allows explorer.exe to listen on any port
• It listens to port 443
• It tries to spawn legitimate binaries from %System% directory and inject its malicious code

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

It adds the following scheduled tasks:

• Task name: {random characters}
  Trigger: Repeat Every 30 mins indefinitely
  Task to be run: %Application Data%\{Existing Folder}\{Random Characters}\{file name}.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).)