Analysis by: Mark Joseph Manahan

ALIASES:

Trojan-Dropper.Win32.Dorifel.zhc (Kasperksy), VirTool:Win32/DelfInject (Microsoft)

 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: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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.

  TECHNICAL DETAILS

Tamaño del archivo 897,024 bytes
Tipo de archivo EXE
Fecha de recepción de las muestras iniciales 14 Feb 2013

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 adds the following folders:

  • {All User's Profile}\{random}
  • {All User's Profile}\{random}\{random 2}
  • {All User's Profile}\{random}\{random 2}\{random 3}
  • {All User's Profile}\{random}\{random 2}\{random 3}\{random 4}

It drops the following files:

  • {All User's Profile}\{random filename}

It drops the following copies of itself into the affected system:

  • {All User's Profile}\{random}\{random 2}\{random 3}\{random 4}\{random filename}.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
{random} = "{All User's Profile}\{random}\{random 2}\{random 3}\{random 4}\{random filename}.exe"

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion
Explore = "BD74A42C-7664A42A"

Other Details

This Trojan connects to the following possibly malicious URL:

  • {BLOCKED}c14.blogspot.com.br
  • {BLOCKED}suszas.hu
  • {BLOCKED}res.com.br