Analysis by: Rhena Inocencio
ALIASES:

Win32/Injector.ELU trojan (ESET)

 PLATFORM:

Windows 2000, Windows Server 2003, Windows XP (32-bit, 64-bit), Windows Vista (32-bit, 64-bit), Windows 7 (32-bit, 64-bit)

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This backdoor 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: 1,261,568 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 07 Mar 2013

Arrival Details

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

  • %System%\Internet Explorer\iexplorer.exe

(Note: %System% is the Windows system folder, which is usually C:\Windows\System32.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer\Run
Policies = "%System%\Internet Explorer\iexplorer.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer\Run
Policies = "%System%\Internet Explorer\iexplorer.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Microsoft = "%System%\Internet Explorer\iexplorer.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Microsoft = "%System%\Internet Explorer\iexplorer.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Active Setup\Installed Components\{2408BV62-4TY1-XMF4-K13R-53E0R6UTOO7V}
StubPath = "%System%\Internet Explorer\iexplorer.exe"

Dropping Routine

This backdoor drops the following files:

  • %Application Data%\Administratorlog.dat
  • %Application Data%\{random filename}.txt
  • %User Temp%\Administrator{number}
  • %User Temp%\anak smu mesum d warnet.3gp

(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, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista and 7.)

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}ciak.dyndns.tv