ALIASES:

Dorifel

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

Canal de infección Dropped by other malware

SIMBOT is a backdoor family that accesses certain remote servers in order to receive commands from a remote attacker. The following are the executed commands on the affected system:

  • Download and executes files
  • Execute a DOS command sent by the remote user
  • Send an encrypted copy of the content of a specified file to its C&C server
  • Sleep for a specified amount of time

It also checks if there are registry keys related to security applications. It does this to avoid detection and easy removal.

  TECHNICAL DETAILS

Residente en memoria Yes

Installation

This Trojan drops the following files:

  • %User Profile%\ntuser.cfg
  • %User Temp%\{random}.tmp

(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 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.)

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

  • %User Profile%\Local Settings\{random}.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.)

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} = "%User Profile%\Local Settings\{random}.exe"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
NTUCF = "rundll32 %User Profile%\ntuser.cfg,Config"

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://{C&C}:443/{random characters}.php?id={random}
  • http://{C&C}:80/{random characters}.php?id={random}
  • {BLOCKED}.{BLOCKED}.206.150:80
  • http://vmompq.{BLOCKED}Z.info/apps/fc.asp
  • http://vmompq.{BLOCKED}Z.info/apps/dw.html