Analysis by: RonJay Kristoffer Caragay
ALIASES:

Worm:Win32/NeksMiner.A (Microsoft); Trojan.BitCoinMiner (Malwarebytes); Mal/Miner-C (Sophos); not-a-virus:RiskTool.Win32.BitCoinMiner.xou (Kaspersky); Riskware/BitCoinMiner (Fortinet); Trojan.Win64.CoinMiner (Ikarus); TR/BitCoinMiner.fra (Avira); a variant of Win32/BitCoinMiner.BX potentially unsafe (ESET-NOD32)

 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: Downloaded from the Internet, Dropped by other malware, Via physical/removable drives

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.

It uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It does not have any backdoor routine.

As of this writing, the said sites are inaccessible.

  TECHNICAL DETAILS

File Size: 3,334,944 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 11 Aug 2015
Payload: Downloads files

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:

  • {Drive Letter}:\{malware filename}.exe
  • %Application Data%\{user name}\{malware filename}.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%\NsCpuCNMiner\NsCpuCNMiner32.exe ← detected as TROJ_COINMINE.NC
  • %Application Data%\NsCpuCNMiner\NsCpuCNMiner64.exe ← detected as TROJ_COINMINE.NC
  • %Application Data%\NsCpuCNMiner\CNminer.exe ← detected as TROJ_COINMINE.NC
  • %Application Data%\NsCpuCNMiner\pools.txt ← contains Bitcoin Mining Pool addresses

(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 non-malicious files:

  • %User Temp%\ns{random}.tmp\inetc.dll - NSIS plugin (Deleted after use)
  • %User Temp%\ns{random}.tmp\System.dll - NSIS plugin (Deleted after use)
  • %User Temp%\ns{random}.tmp\nsExec.dll - NSIS plugin (Deleted after use)

(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 uses the Windows Task Scheduler to add a scheduled task that executes the copies it drops.

It creates the following folders:

  • %Application Data%\NsCpuCNMiner
  • %User Temp%\ns{random}.tmp

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

  • %User Startup%\{malware filename}.exe ← copy of itself

(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 adds the following shared folders into which it drops copies of itself:

  • %Application Data%\{user name}

(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 copies of itself in all physical and removable drives:

  • {Drive Letter}:\{malware filename}.exe

It uses the following user name and password to gain access to password-protected shares:

  • administrator
  • admin
  • adm
  • àäìèíèñòðàòîð
  • àäìèí
  • user
  • test
  • system
  • office
  • Sveta
  • guest
  • tivoli
  • symbiator
  • qwerty
  • login
  • support
  • manager
  • users
  • computer
  • windows
  • pc
  • asus
  • director
  • sklad
  • moderator
  • service
  • root
  • usr
  • temp
  • tester
  • user1
  • user2
  • user3
  • sergey
  • oleg
  • lab
  • bughalter
  • 1
  • a
  • q
  • 123456
  • ñêëàä
  • adminadmin
  • radmin
  • admin1
  • account
  • qwert
  • arcserve
  • admins
  • èìüÿ-ïîëüüçîâàòåëüÿ
  • backup
  • welcome
  • anna
  • ìàãàçèí
  • áóõãàëòåð
  • elena
  • irina
  • natasha
  • administrators
  • 123
  • 1234
  • remote
  • 12345678
  • lena
  • áóõ
  • ãëáóõ
  • êàññèð
  • server
  • demo
  • administrator
  • adm
  • admin
  • Admin
  • password
  • pass
  • àäìèíèñòðàòîð
  • àäìèí
  • test
  • system
  • abc123
  • qwerty
  • pass1
  • password1
  • derok080880
  • admin1
  • admin123
  • user
  • user1
  • 123
  • 1234
  • 0
  • Ïàðîëüü1
  • guest
  • welcome
  • support
  • computer
  • irina
  • administrators
  • pc
  • Administrator
  • Ïàðîëüü
  • ïàðîëüü
  • ïàðîëüü1
  • security
  • sysadm
  • root
  • demo
  • temp
  • share
  • write
  • full
  • 2011
  • read
  • 123456
  • access
  • server
  • local
  • tmesrvd
  • arcada
  • login
  • user2
  • adminadmin
  • qwert
  • director
  • qwerty1
  • Admin123
  • windows
  • sklad
  • tester
  • 1
  • pwd
  • usr
  • passwordpassword
  • P@ssw0rd
  • flvbybcnhfnjh
  • both
  • office
  • natasha
  • anna
  • 111
  • @dmin
  • manager
  • lab
  • tivoli
  • gfhjkm
  • cthdth
  • 123321
  • as400
  • 1
  • ronaldo
  • liverpool
  • 12345
  • !@#$
  • 123123
  • symbiator
  • files
  • 55555
  • user1
  • user2
  • user3
  • qwert
  • oleg
  • lena
  • users
  • asus
  • 2010
  • èìüÿ-ïîëüüçîâàòåëüÿ
  • èìüÿ-êîìïàíèè
  • qwerty123
  • moderator
  • service
  • lab
  • arcserve
  • backup
  • xxx
  • 2009
  • 666
  • 777
  • 000
  • 11111
  • 54321
  • ñêëàä
  • radmin
  • admin1
  • pass1234
  • 2009
  • 0
  • a
  • q
  • 12345678
  • account
  • demo
  • server
  • natasha
  • sergey
  • *
  • èìüÿ_ìàøèíû

Backdoor Routine

This worm does not have any backdoor routine.

Download Routine

This worm connects to the following URL(s) to download its component file(s):

  • http://{BLOCKED}t.ru/tmp.php

It saves the files it downloads using the following names:

  • %User Temp%\tmp.exe

(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.)

As of this writing, the said sites are inaccessible.

NOTES:
The created scheduled task is used to execute copies of itself to another system within the network upon logon.

It does not have rootkit capabilities.

It does not exploit any vulnerability.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.848.05
FIRST VSAPI PATTERN DATE: 11 Aug 2015
VSAPI OPR PATTERN File: 11.849.00
VSAPI OPR PATTERN Date: 12 Aug 2015

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

Note that not all files, folders, and registry keys and entries are installed on your computer during this malware's/spyware's/grayware's execution. This may be due to incomplete installation or other operating system conditions. If you do not find the same files/folders/registry information, please proceed to the next step.

Step 3

Remove malware/grayware files dropped/downloaded by WORM_COINMINE.B. (Note: Please skip this step if the threats listed below have already been removed.)

Step 4

Restart in Safe Mode

[ Learn More ]

Step 5

Search and delete these files

[ 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.
  • %Application Data%\NsCpuCNMiner\pools.txt
  • %User Temp%\ns{random}.tmp\inetc.dll
  • %User Temp%\ns{random}.tmp\System.dll
  • %User Temp%\ns{random}.tmp\nsExec.dll
  • %User Temp%\tmp.exe

Step 6

Search and delete this folder

[ Learn More ]
Please make sure you check the Search Hidden Files and Folders checkbox in the More advanced options option to include all hidden folders in the search result.
  • %Application Data%\NsCpuCNMiner
  • %User Temp%\ns{random}.tmp
  • %Application Data%\{user name}

Step 7

Delete the Scheduled Tasks added by this malware/grayware

[ Learn More ]

To delete the added Scheduled Task file:

For Windows 2000, Windows XP, and Windows Server 2003:

  1. Open the Windows Scheduled Tasks. To do this, click Start>Programs>Accessories>System Tools>Scheduled Tasks.
  2. Double-click on a .JOB file.
  3. Check if the malware path and file name exists in the .JOB file. To do this, check the value in the Run field.
  4. If found, select the .JOB file then press SHIFT+DELETE to permanently delete the file.
  5. Repeat the steps above for the remaining .JOB files.

For Windows Vista, Windows 7, Windows Server 2008, Windows 8, Windows 8.1, and Windows Server 2012:

  1. Open the Windows Task Scheduler. To do this:
    • On Windows Vista, Windows 7, and Windows Server 2008, click Start, type taskschd.msc in the Search input field, then press Enter.
    • On Windows 8, Windows 8.1, and Windows Server 2012, right-click on the lower left corner of the screen, click Run, type taskschd.msc, then press Enter.
  2. In the left panel of the Task Scheduler Window, click Task Scheduler Library.
  3. In the upper-middle panel, click a Task.
  4. In the lower middle panel, click the Actions tab
  5. Check if the malware path and file name exists in the task. To do this, check the value in the Details column under the Actions tab.
  6. If found, select the task and press DELETE and click Yes to delete the task.
  7. Repeat the steps above for the remaining tasks.

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_COINMINE.B. 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.

Step 9

Scan your computer with your Trend Micro product to delete files detected as WORM_COINMINE.B. 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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