BKDR_NANOBOT.AUSX

 Analysis by: Byron Jon Gelera

 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:

470,002 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

11 Apr 2017

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 adds the following folders:

  • %System Root%\U5v8R11awsU5v8R11aws (Hidden)

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It drops the following files:

  • %User Profile%\U5v8R11aws\FJFfFb.vbs
  • %User Profile%\U5v8R11aws\x
  • %User Profile%\U5v8R11aws\690r.dll
  • %System Root%\U5v8R11awsU5v8R11aws\U5v8R11aws.vbs
  • %System Root%\U5v8R11awsU5v8R11aws\x
  • %System Root%\U5v8R11awsU5v8R11aws\690r.dll
  • %Application Data%\{GUID}\Logs\{user name}\KB_{random}.dat
  • %Application Data%\{GUID}\run.dat
  • %Program Files%\PCI Service\pcisv.exe

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003, or C:\Users\{user name} on Windows Vista and 7.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %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.)

Other System Modifications

This Backdoor adds the following registry entries as part of its installation routine:

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\RunOnce
U5v8R11aws = %System Root%\U5v8R11awsU5v8R11aws\U5v8R11aws.vbs

Other Details

This Backdoor connects to the following possibly malicious URL:

  • {BLOCKED}.{BLOCKED}.143.104
  • {BLOCKED}7.{BLOCKED}s.net

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

13.334.02

FIRST VSAPI PATTERN DATE:

11 Apr 2017

VSAPI OPR PATTERN File:

13.335.00

VSAPI OPR PATTERN Date:

12 Apr 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

Restart in Safe Mode

[ Learn More ]

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\RunOnce
    • U5v8R11aws = %System Root%\U5v8R11awsU5v8R11aws\U5v8R11aws.vbs

Step 5

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.
  • %System Root%\U5v8R11awsU5v8R11aws

Step 6

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.  
  • %User Profile%\U5v8R11aws\FJFfFb.vbs
  • %User Profile%\U5v8R11aws\x
  • %User Profile%\U5v8R11aws\690r.dll
  • %Application Data%\{GUID}\Logs\{user name}\KB_{random}.dat
  • %Application Data%\{GUID}\run.dat
  • %Program Files%\PCI Service\pcisv.exe

Step 7

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


Did this description help? Tell us how we did.