BKDR_NANOCORE.SM

October 09, 2017
 Analysis by: Joselyn Canuela
 ALIASES:

Backdoor.MSIL.NanoBot.ymb (Kaspersky), Backdoor:MSIL/Noancooe.C (Microsoft), Msil.Backdoor.Nanobot.Wnlu (Tencent)

 PLATFORM:

Windows

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

  • Threat Type: Backdoor

  • Destructiveness: No

  • Encrypted: No

  • In the wild: Yes

  OVERVIEW

Infection Channel:

Dropped by other malware, Downloaded from the Internet

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.

It executes commands from a remote malicious user, effectively compromising the affected system.

It gathers certain information on the affected computer.

  TECHNICAL DETAILS

File Size:

745,472 bytes

File Type:

EXE

Memory Resident:

No

Initial Samples Received Date:

25 Sep 2017

Payload:

Connects to URLs/IPs, Executes commands, Steals information

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 files:

  • %Application Data%\{random CLSID}\run.dat
  • %Application Data%\{random CLSID}\Logs{User}\KB_{random}.dat - where keylogger data will be saved

(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 into the affected system:

  • %Application Data%\{random CLSID}\PCI Service\pcisv.exe - when executed as non-admin
  • %Program Files%\PCI Service\pcisv.exe - when executed as admin

(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.. %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.)

It creates the following folders:

  • %Application Data%\{random CLSID}
  • %Application Data%\{random CLSID}\PCI Service
  • %Application Data%\{random CLSID}\Logs\{User}
  • %Program Files%\PCI Service

(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.. %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.)

It adds the following mutexes to ensure that only one of its copies runs at any one time:

  • Global\{CLSID}

Autostart Technique

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

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Run
PCI Service = %Program Files%\PCI Service\pcisv.exe

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
PCI Service = %Application Data%\random CLSID}\PCI Service\pcisv.exe

Backdoor Routine

This Backdoor executes the following commands from a remote malicious user:

  • Manage its backdoor file
    • Update itself
    • Restart connection
    • Terminate itself
    • Uninstall itself
  • System Control
    • Restart Machine
    • Shutdown Machine
    • Locks the machine
    • Browse Directory
    • View Task Manager
    • Edit Registry
    • Remote CMD
    • Used to DDOS
    • Mouse swap
    • Remote Execution(from web/file)
    • Remote Script Execution
      • Html
      • Batch
      • VBS
      • Python
      • Java
      • PHP
    • Recover Browser Passwords
    • Open CDTray
    • Monitor Keyboard
    • Keyboard logging
    • View Monitor/webcam
    • Control Mouse
    • Send Messages / Chat with the attacker

It connects to the following URL(s) to send and receive commands from a remote malicious user:

  • {BLOCKED}.{BLOCKED}.181.70:7893

Information Theft

This Backdoor gathers the following information on the affected computer:

  • CPU and OS Information
  • Malware File Name
  • Installed Anti-Virus/Anti-Spyware

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.694.05

FIRST VSAPI PATTERN DATE:

02 Oct 2017

VSAPI OPR PATTERN File:

13.695.00

VSAPI OPR PATTERN Date:

03 Oct 2017

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

Identify and terminate files detected as BKDR_NANOCORE.SM

[ 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_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
    • PCI Service = "%Program Files%\PCI Service\pcisv.exe"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • PCI Service = "%Application Data%\random CLSID}\PCI Service\pcisv.exe"

Step 5

Search and delete these folders

[ 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%\{random CLSID}
  • %Program Files%\PCI Service

Step 6

Scan your computer with your Trend Micro product to delete files detected as BKDR_NANOCORE.SM. 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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