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TrojanSpy.Win32.BANKER.AMC

January 12, 2019
 Analysis by: John Donnie Celestre
 ALIASES:

HEUR:Trojan.Win32.Agent.gen (KASPERSKY)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 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.

  TECHNICAL DETAILS

File Size:

7,154,688 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

10 Jan 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 and executes them:

  • %User Temp%\default.exe

(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.)

It drops the following files:

  • %AppDataLocal%\Microsoft Windows\Config.ini
  • %AppDataLocal%\Microsoft Windows\libeay32.dll
  • %AppDataLocal%\Microsoft Windows\ssleay32.dll
  • %AppDataLocal%\Microsoft Windows\sqlite3.dll
  • %AppDataLocal%\Microsoft Windows\taskWin.exe
  • %AppDataLocal%\Microsoft Windows\winPrsv.exe
  • %AppDataLocal%\Microsoft Windows\default.exe

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

It creates the following folders:

  • %AppDataLocal%\Microsoft Windows

(Note: %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Local 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_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Kernel System = "%AppDataLocal%\Microsoft Windows\taskWin.exe"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Control Network = "%AppDataLocal%\Microsoft Windows\winPrsv.exe"

Other System Modifications

This Trojan Spy modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
EnableBalloonTips = 0

(Note: The default value data of the said registry entry is 1.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Policies\
System
EnableLUA = 0

(Note: The default value data of the said registry entry is 1.)

  SOLUTION

Minimum Scan Engine:

9.850

FIRST VSAPI PATTERN FILE:

14.744.04

FIRST VSAPI PATTERN DATE:

11 Jan 2019

VSAPI OPR PATTERN File:

14.745.00

VSAPI OPR PATTERN Date:

12 Jan 2019

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
    • Kernel System = "%AppDataLocal%\Microsoft Windows\taskWin.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    • Control Network = "%AppDataLocal%\Microsoft Windows\winPrsv.exe"

Step 5

Restore these modified registry values

[ Learn More ]

Important:Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this only if you know how to or you can seek your system administrator's help. You may also check out this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: EnableBalloonTips = 0
      To: EnableBalloonTips = 1
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
    • From: EnableLUA = 0
      To: EnableLUA = 1

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.
  • %AppDataLocal%\Microsoft Windows\Config.ini
  • %AppDataLocal%\Microsoft Windows\libeay32.dll
  • %AppDataLocal%\Microsoft Windows\ssleay32.dll
  • %AppDataLocal%\Microsoft Windows\sqlite3.dll
  • %AppDataLocal%\Microsoft Windows\taskWin.exe
  • %AppDataLocal%\Microsoft Windows\winPrsv.exe
  • %AppDataLocal%\Microsoft Windows\default.exe
  • %User Temp%\default.exe

Step 7

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