BKDR_BIFROSE.WINB

 Analysis by: Joachim Suico

 ALIASES:

Backdoor:Win32/Bifrose.HM (Microsoft); Trojan horse BackDoor.Bifrose.PBR (AVG); W32/Bifrose.NSZ!tr (Fortinet)

 PLATFORM:

Windows

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

  • 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:

32,640 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Apr 2015

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:

  • %Program Files%\netko\netko.exe (Windows XP and below)
  • %Application Data%\netko\netko.exe (Windows Vista and above)

(Note: %Program Files% is the Program Files folder, where it usually is C:\Program Files on all Windows operating system versions; C:\Program Files (x86) for 32-bit applications running on Windows 64-bit operating systems.. %Application Data% is the Application Data folder, where it usually is C:\Documents and Settings\{user name}\Application Data on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Roaming on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), Windows Server 2008, and Windows Server 2012.)

Other System Modifications

This backdoor adds the following registry entries:

HKEY_CURRENT_USER\Software\netko
pnp = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\netko
Ask = "{hex values}"

Other Details

This backdoor connects to the following possibly malicious URL:

  • alive.{BLOCKED}e.com