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Trojan.Win32.DAPATO.AK

October 14, 2019
 PLATFORM:

Windows

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

  • Threat Type: Trojan

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Trojan 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:

933,760 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

14 Oct 2019

Arrival Details

This Trojan 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 adds the following processes:

  • %User Temp%\RarSFX0\update_service.exe -install
  • %User Temp%\RarSFX0\service_monitor.exe -install "Aisino Deamon Services"
  • %Application Data%\Nuoabaifegbf.exe
  • %Windows%\Microsoft.NET\Framework\v4.0.30319\mscorsvw.exe
  • %System%\svchost.exe -k LocalServiceAndNoImpersonation
  • %Windows%\Microsoft.NET\Framework64\v4.0.30319\mscorsvw.exe
  • %System%\sppsvc.exe
  • "%System Root%\Program Files\Windows Media Player\wmpnetwk.exe"
  • %System%\svchost.exe -k WerSvcGroup

(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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System% is the Windows system folder, where it usually is C:\Windows\System32 on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %User Profile%\AppData
  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft
  • %System Root%\Users
  • %User Temp%\RarSFX0

(Note: %User Profile% is the current user's profile folder, which is usually C:\Documents and Settings\{user name} on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name} on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %Windows% is the Windows folder, where it usually is C:\Windows on all Windows operating system versions.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Autostart Technique

This Trojan registers itself as a system service to ensure its automatic execution at every system startup by adding the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
ImagePath = "%Application Data%\Nuoabaifiich.exe -svc Aisino Deamon Services"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nuo Update Monitor
ImagePath = "%Application Data%\Nuoabaifegbf.exe"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Rpc Monitor
ImagePath = "%Application Data%\Nuoabaifiich.exe -svc Aisino Deamon Services"

Other System Modifications

This Trojan deletes the following files:

  • %Windows%\LastGood.Tmp

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

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Paths\
NuoYan

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Paths\
NuoYan
update_service = "%System Root%"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
DisplayName = "Rpc Monitor"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
WOW64 = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
ObjectName = "LocalSystem"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Rpc Monitor
Description = "\xe5\x85\xb3\xe9\x94\xae\xe6\x9c\x8d\xe5\x8a\xa1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\App Paths\
NuoYan
service_monitor = "%System Root%"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nuo Update Monitor
DisplayName = "Nuo Update Monitor"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Nuo Update Monitor
Start = "SERVICE_AUTO_START"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Rpc Monitor
DisplayName = "Rpc Monitor"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Rpc Monitor
Start = "SERVICE_AUTO_START"

Dropping Routine

This Trojan drops the following files:

  • %Application Data%\Nuoabaifegbf.exe
  • %User Temp%\RarSFX0\update_service.exe
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
  • %User Temp%\RarSFX0\service_monitor.exe
  • %Application Data%\Nuoabaifiich.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(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Roaming on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %User Temp% is the current user's Temp folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local\Temp on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).. %AppDataLocal% is the Local Application Data folder, which is usually C:\Documents and Settings\{user name}\Local Settings\Application Data on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\Users\{user name}\AppData\Local on Windows Vista, 7, 8, 8.1, 2008(64-bit), 2012(64-bit) and 10(64-bit).)

Other Details

This Trojan connects to the following possibly malicious URL:

  • http://update.{BLOCKED}s.com.cn/interfaceCtr/getVersion.do?version=0.0.0.0&i_type=36
  • http://www.{BLOCKED}u.com

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.850

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

Identify and terminate files detected as Trojan.Win32.DAPATO.AK

[ 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 3

Delete this registry key

[ 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\App Paths
    • NuoYan
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services
    • Rpc Monitor

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\App Paths\NuoYan
    • update_service = "%System Root%"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • Type = "16"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • DisplayName = "Rpc Monitor"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • WOW64 = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • ObjectName = "LocalSystem"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Rpc Monitor
    • Description = "\xe5\x85\xb3\xe9\x94\xae\xe6\x9c\x8d\xe5\x8a\xa1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths\NuoYan
    • service_monitor = "%System Root%"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nuo Update Monitor
    • DisplayName = "Nuo Update Monitor"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Nuo Update Monitor
    • Start = "SERVICE_AUTO_START"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Rpc Monitor
    • DisplayName = "Rpc Monitor"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Rpc Monitor
    • Start = "SERVICE_AUTO_START"

Step 5

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%\Nuoabaifegbf.exe
  • %User Temp%\RarSFX0\update_service.exe
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb
  • %User Temp%\RarSFX0\service_monitor.exe
  • %Application Data%\Nuoabaifiich.exe

Step 6

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.
  • %User Profile%\AppData
  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft
  • %System Root%\Users
  • %User Temp%\RarSFX0

Step 7

Scan your computer with your Trend Micro product to delete files detected as Trojan.Win32.DAPATO.AK. 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 the following Trend Micro Support pages for more information:

Step 8

Restore this file from backup only Microsoft-related files will be restored. If this malware/grayware also deleted files related to programs that are not from Microsoft, please reinstall those programs on you computer again.

  • %Windows%\LastGood.Tmp


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