Analysis by: Mark Joseph Manahan
ALIASES:

(Win32/TrojanDownloader.VB.PVA trojan (Eset), Trojan:Win32/Malagent (Microsoft), W32/Injector.FFNX!tr (Fortinet)

 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

Tamaño del archivo 30,208 bytes
Tipo de archivo EXE
Residente en memoria Yes
Fecha de recepción de las muestras iniciales 27 Jun 2012

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:

  • %User Profile%\chrome.exe
  • %User Profile%\My Documents\chrome.exe
  • %User Startup%\chrome.exe
  • %Desktop%\chrome.exe
  • %User Profile%\Downloads\chrome.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %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, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.. %Desktop% is the current user's desktop, which is usually C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\Desktop on Windows Vista and 7.)

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\Run
a = "%Desktop%\chrome.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
b = "%User Profile%\My Documents\chrome.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
c = "%User Profile%\Downloads\chrome.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
d = "%User Profile%\chrome.exe"

Other Details

This backdoor connects to the following possibly malicious URL:

  • {BLOCKED}1.hopto.org