Analysis by: Michael Jay Villanueva
ALIASES:

Trojan:Win32/CoinMiner!rfn (Microsoft); Trojan-CoinMiner (McAfee); W32/Miner.AYF!tr (Fortinet)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm 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: 3,552,168 bytes
File Type: EXE
Initial Samples Received Date: 02 Jun 2016

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system and executes them:

  • %Application Data%\NsMiner\IMG001.exe

(Note: %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.)

It drops the following files:

  • %Application Data%\NsMiner\pools.txt
  • %Application Data%\NsMiner\makensis.exe
  • %Application Data%\NsMiner\NsCpuCNMiner32.exe
  • %Application Data%\NsMiner\NsCpuCNMiner64.exe

(Note: %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.)

It creates the following folders:

  • %Application Data%\NsMiner\

(Note: %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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{Default} = %Application Data%\NsMiner\IMG001.exe

It drops the following file(s) in the Windows Startup folder to enable its automatic execution at every system startup:

  • %User Startup%\Run.lnk

(Note: %User Startup% is the current user's Startup folder, which is usually C:\Documents and Settings\{user}\Start Menu\Programs\Startup on Windows 2000 and XP, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup on Windows Vista, 7, and 8.)

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • {Drive Letter}:\IMG001.exe

Other Details

This worm connects to the following possibly malicious URL:

  • http://{string}.ru/test.html
  • http://{string}.ru/stat.html
  • http://{string}.ru/text.html
    where {string} may be of the following:
    • {BLOCKED}s
    • {BLOCKED}ti
    • {BLOCKED}ts
    • {BLOCKED}est
    • {BLOCKED}s
    • {BLOCKED}ts
    • {BLOCKED}t
    • {BLOCKED}est
    • {BLOCKED}sy