PUA.Win32.MaoWifi.A

October 25, 2019
 ALIASES:

Generic PUP.mn. (McAfee); Trojan.Gen.2 (Symantec); Trojan.Win32.Generic!BT (Sunbelt)

 PLATFORM:

Windows

 OVERALL RISK RATING:
 REPORTED INFECTION:
 SYSTEM IMPACT RATING:
 INFORMATION EXPOSURE:

  • Threat Type: Potentially Unwanted Application

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This Potentially Unwanted Application 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:

168,992 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

25 Oct 2019

Arrival Details

This Potentially Unwanted Application 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 Potentially Unwanted Application adds the following processes:

  • %System%\vssvc.exe
  • %User Temp%\561b05aa5581646c5c4726b5557d867fbdd1a3a9.quarantine
  • %System%\svchost.exe -k LocalService
  • %System%\svchost.exe -k netsvcs
  • %System%\svchost.exe -k LocalSystemNetworkRestricted
  • %System%\svchost.exe -k WerSvcGroup
  • %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%\WerFault.exe -u -p 2084 -s 344
  • %System%\WerFault.exe -u -p 2388 -s 1232
  • %System%\WerFault.exe -u -p 1224 -s 200
  • %System%\WerFault.exe -u -p 1224 -s 44
  • %System%\WerFault.exe -u -p 2060 -s 172
  • %System%\WerFault.exe -u -p 2060 -s 168
  • %System%\WerFault.exe -u -p 2060 -s 184
  • %System%\WerFault.exe -u -p 2752 -s 180
  • %System%\WerFault.exe -u -p 2752 -s 176
  • %System%\WerFault.exe -u -p 1556 -s 1252

(Note: %System% is the Windows system folder, where it usually is C:\Windows\System32 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).. %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.)

It creates the following folders:

  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft

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

Autostart Technique

This Potentially Unwanted Application 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\MaohaWifiNetPro
ImagePath = "\??\%User Temp%\MaoHaWiFiNet64.sys"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiSvr
ImagePath = "{malware path and file name}.quarantine"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiNetPro
ImagePath = "%User Temp%\MaoHaWiFiNet64.sys"

Other System Modifications

This Potentially Unwanted Application deletes the following files:

  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_96.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_32.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_1024.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_256.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_sr.db
  • %AppDataLocal%\IconCache.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_idx.db

(Note: %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).)

It adds the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\VSS\Diag\
Registry Writer

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\VSS\Diag\
COM+ REGDB Writer

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\VSS\Diag\
ASR Writer

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\VSS\Diag\
Shadow Copy Optimization Writer

It adds the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro
Type = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro
Start = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro
ErrorControl = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro
DisplayName = "MaohaWifiNetPro"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\MaohaWifiNetPro
WOW64 = "1"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\SstpSvc
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\SstpSvc
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\dot3svc
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\dot3svc
Start = "2"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Wlansvc
Type = "16"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\Wlansvc
Start = "2"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache
UIStatus = "560"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\HomeGroup\
UIStatusCache
OnlyMember = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0000
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0000
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0000
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0003
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0003
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0003
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0001
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0001
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0001
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0002
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0002
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0002
EnableForOutboundRouting = "0"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\NetworkList\
Nla\Cache\Intranet
{89BCDCB3-5725-45A2-94AB-2D6B641209B0} = "\x00PV\xbcK\xa3"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiSvr
DisplayName = "MaohaWiFiService"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiSvr
Start = "SERVICE_AUTO_START"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiNetPro
DisplayName = "MaohaWifiNetPro"

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\MaohaWifiNetPro
Start = "SERVICE_SYSTEM_START"

It modifies the following registry entries:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\RasMan
Type = "16"

(Note: The default value data of the said registry entry is 20.)

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
services\RasMan
Start = "2"

(Note: The default value data of the said registry entry is 3.)

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0004
EnableForRas = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0004
EnableForRouting = "0"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\
0004
EnableForOutboundRouting = "0"

Dropping Routine

This Potentially Unwanted Application drops the following files:

  • %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
  • %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
  • %User Temp%\log\MaohaWifiSvr.log
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb

(Note: %All Users Profile% is the common user's profile folder, which is usually C:\Documents and Settings\All Users on Windows 2000(32-bit), XP, and Server 2003(32-bit), or C:\ProgramData 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).)

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 PUA.Win32.MaoWifi.A

[ 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\SYSTEM\CurrentControlSet\services
    • MaohaWifiNetPro
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup
    • UIStatusCache
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Diag
    • Registry Writer
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Diag
    • COM+ REGDB Writer
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Diag
    • ASR Writer
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VSS\Diag
    • Shadow Copy Optimization Writer

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\SYSTEM\CurrentControlSet\services\MaohaWifiNetPro
    • Type = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MaohaWifiNetPro
    • Start = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MaohaWifiNetPro
    • ErrorControl = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MaohaWifiNetPro
    • DisplayName = "MaohaWifiNetPro"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MaohaWifiNetPro
    • WOW64 = "1"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\SstpSvc
    • Type = "16"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\SstpSvc
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\dot3svc
    • Type = "16"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\dot3svc
    • Start = "2"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Wlansvc
    • Type = "16"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Wlansvc
    • Start = "2"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup\UIStatusCache
    • UIStatus = "560"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\HomeGroup\UIStatusCache
    • OnlyMember = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0000
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0000
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0000
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0003
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0003
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0003
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0001
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0001
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0001
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0002
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0002
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0002
    • EnableForOutboundRouting = "0"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Nla\Cache\Intranet
    • {89BCDCB3-5725-45A2-94AB-2D6B641209B0} = "\x00PV\xbcK\xa3"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MaohaWifiSvr
    • DisplayName = "MaohaWiFiService"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MaohaWifiSvr
    • Start = "SERVICE_AUTO_START"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MaohaWifiNetPro
    • DisplayName = "MaohaWifiNetPro"
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MaohaWifiNetPro
    • Start = "SERVICE_SYSTEM_START"

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_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RasMan
    • From: Type = "16"
      To: Type = ""20""
  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\RasMan
    • From: Start = "2"
      To: Start = ""3""
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0004
    • EnableForRas = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0004
    • EnableForRouting = "0"
  • In HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\CLASS\{4D36E972-E325-11CE-BFC1-08002BE10318}\0004
    • EnableForOutboundRouting = "0"

Step 6

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.
  • %All Users Profile%\Microsoft\Windows\DRM\drmstore.hds
  • %All Users Profile%\Microsoft\Windows\DRM\v3ks.sec
  • %User Temp%\log\MaohaWifiSvr.log
  • %AppDataLocal%\Microsoft\Media Player\CurrentDatabase_372.wmdb

Step 7

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.
  • %Windows%\ServiceProfiles\NetworkService\AppData\Local\Microsoft

Step 8

Scan your computer with your Trend Micro product to delete files detected as PUA.Win32.MaoWifi.A. 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 9

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.

  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_96.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_32.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_1024.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_256.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_sr.db
  • %AppDataLocal%\IconCache.db
  • %AppDataLocal%\Microsoft\Windows\Explorer\thumbcache_idx.db


Did this description help? Tell us how we did.