Modified by: Kiyoshi Obuchi

ALIASES:

Trojan:Win32/Fuerboos.C!cl (Microsoft); Trojan-Banker.Win32.Gozi.cgm (Kaspersky)

 PLATFORM:

Windows

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

  • Threat Type: Trojan Spy

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan Spy arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It deletes itself after execution.

  TECHNICAL DETAILS

File Size: 545,280 bytes
File Type: EXE
Initial Samples Received Date: 16 Apr 2019

Arrival Details

This Trojan Spy 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 Trojan Spy drops the following copies of itself into the affected system:

  • %Application Data%\Microsoft\Bitssole\defrvmgr.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

It adds the following processes:

  • cmd /C nslookup myip.opendns.com resolver1.opendns.com %User Temp%\D258.bi1
  • cmd /C echo -------- %User Temp%\D258.bi1
  • nslookup myip.opendns.com resolver1.opendns.com

It creates the following folders:

  • %Application Data%\Microsoft\Bitssole

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
authtlib = "%Application Data%\Microsoft\Bitssole\defrvmgr.exe"

Dropping Routine

This Trojan Spy drops the following files:

  • %User Temp%\D258.bi1
  • %System Root%\test\test32.dll
  • %Application Data%\Microsoft\{random values}

(Note: %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, and 8.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, and 8.)

Other Details

This Trojan Spy connects to the following possibly malicious URL:

  • http://{BLOCKED}-medicine.at/{random path}
  • http://{BLOCKED}lzaelooop11.club
  • http://resolver1.{BLOCKED}s.com
  • http://{BLOCKED}2.{BLOCKED}2.67.208.in-addr.arpa
  • http://myip.{BLOCKED}s.com

It deletes itself after execution.

  SOLUTION

Minimum Scan Engine: 9.850
FIRST VSAPI PATTERN FILE: 14.942.03
FIRST VSAPI PATTERN DATE: 16 Apr 2019
VSAPI OPR PATTERN File: 14.943.00
VSAPI OPR PATTERN Date: 17 Apr 2019

Step 1

Before doing any scans, Windows 7, Windows 8, Windows 8.1, and Windows 10 users must disable System Restore to allow full scanning of their computers.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

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
    • authtlib = "%Application Data%\Microsoft\Bitssole\defrvmgr.exe"

Step 4

Search and delete these components

[ Learn More ]
There may be some components 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%\Microsoft\{random values}
  • %User Temp%\D258.bi1
  • %System Root%\test\test32.dll

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.
  • %Application Data%\Microsoft\Bitssole

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as TrojanSpy.Win32.URSNIF.TIABOEBE. 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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