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WORM_COINMINER.FHE

October 19, 2016
 Analysis by: Jeanne Jocson
 ALIASES:

Trojan:Win32/CoinMiner!rfn (Microsoft), Trojan.Win32.Miner.ays (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Propagates via shared drives, Propagates via FTP

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:

1,578,496 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

18 Oct 2016

Payload:

Executes Bitcoin Miners

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 files:

  • %User Temp%\pools.txt - contains Bitcoin Mining Pool addresses

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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 and executes the following files:

  • %User Temp%\NsCpuCNMiner32.exe - detected as TROJ_COINMINER.FHE

(Note: %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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
Run = "{malware path and filename}"

Other Details

This worm does the following:

  • This Trojan connects to the website http://{domain name}/test.html?{7 random numbers}to read its configuration file. The variable {domain name} may be any of the following:

  • {BLOCKED}est.ru
  • {BLOCKED}s.ru
  • {BLOCKED}est.ru
  • {BLOCKED}y.ru
  • {BLOCKED}s.ru
  • {BLOCKED}t.ru
  • {BLOCKED}s.ru
  • {BLOCKED}ts.ru
  • {BLOCKED}i.ru

  • The configuration file contains the parameters to be used when executing the drop NsCpuCNMiner32.exe file.

  • It executes the file %User Temp%\NsCpuCNMiner32.exe {parameter from the configuration file}. An example of the parameter is below:
    • -dbg -1 -o {pool address} -t 0 -u {Wallet Address} -p x
  • This Trojan is used for CryptoNote (cryptocurrency) CPU Mining. It can mine the following supported coins:
    • AeonCoin(AEON)
    • Bytecoin (BCN)
    • Dashcoin (DSH)
    • DuckDuckCoin (DUCK)
    • Fantomcoin (FCN)
    • Monero (XMR)
    • MonetaVerde(MCN)
    • OneEvilCoin(OEC)
    • ORION
    • QuazarCoin (QCN)
  • It drops copies of itself in all drives using the following command line:
    • xcopy /c for %%i in (A B C D E F G H J K L M N O P R S T Q U Y I X V X W Z) do xcopy /y ""%s"" %%i:\
  • It generates random IP address where it attempts to connect as FTP. It then drops a copy of itself as "Photo.scr".
  • It searches for ".php" files in the FTP folder and inserts an iframe code to automatically executed the dropped file "Photo.scr" when the PHP file is opened.

  SOLUTION

Minimum Scan Engine:

9.800

FIRST VSAPI PATTERN FILE:

12.844.04

FIRST VSAPI PATTERN DATE:

18 Oct 2016

VSAPI OPR PATTERN File:

12.845.00

VSAPI OPR PATTERN Date:

19 Oct 2016

Step 1

Before doing any scans, Windows XP, Windows Vista, and Windows 7 users must disable System Restore to allow full scanning of their computers.

Step 2

Remove the malware/grayware file dropped/downloaded by WORM_COINMINER.FHE. (Note: Please skip this step if the threat(s) listed below have already been removed.)

     TROJ_COINMINER.FHE

Step 3

Identify and terminate files detected as WORM_COINMINER.FHE

[ Learn More ]
  1. Windows Task Manager may not display all running processes. In this case, please use a third-party process viewer, preferably Process Explorer, to terminate the malware/grayware/spyware file. You may download the said tool here.
  2. If the detected file is displayed in either Windows Task Manager or Process Explorer but you cannot delete it, restart your computer in safe mode. To do this, refer to this link for the complete steps.
  3. If the detected file is not displayed in either Windows Task Manager or Process Explorer, continue doing the next steps.

Step 4

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • Run = "{malware path and filename}"

Step 5

Search and delete this file

[ Learn More ]
There may be some files that are hidden. Please make sure you check the Search Hidden Files and Folders checkbox in the "More advanced options" option to include all hidden files and folders in the search result. %User Temp%\pools.txt

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_COINMINER.FHE. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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