Analysis by: David John Agni
ALIASES:

W32/MewsSpy.Q!tr (Fortinet), Virus.Win32.MewsSpy (Ikarus), Virus:Win32/Mewsei.A (Microsoft)

 PLATFORM:

Windows

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

  • Threat Type: File infector

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This file infector 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: 342,744 bytes
File Type: EXE
Memory Resident: Yes
Initial Samples Received Date: 17 Apr 2015

Arrival Details

This file infector 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 file infector drops the following copies of itself into the affected system:

  • %Application Data%\{random folder}\{random filename 2}.exe
  • %ProgramData%\{random folder}\{random filename 2}.exe

(Note: %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.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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.)

It drops the following file(s)/component(s):

  • %Application Data%\{random folder}\{random filename}.mui
  • %Application Data%\{random folder}\{random folder 2}\{random filename 3}.sys
  • %ProgramData%\{random folder}\{random filename 4}.ocx
  • %ProgramData%\{random folder}\{random filename 5}.mui
  • %ProgramData%\{random folder}\{random filename 6}.cat
  • %ProgramData%\{random folder}\{random filename 7}
  • %ProgramData%\{random folder}\{random folder 3}\{random filename 8}.sys
  • %ProgramData%\{random folder}\{random folder 3}\{random filename 9}.cat
  • %ProgramData%\{random folder}\{random folder 4}\{random folder 5}\{random filename 10}.sys
  • %ProgramData%\{random folder}\{random folder 4}\{random folder 5}\{random filename 11}.drv
  • %ProgramData%\{random folder}\{random folder 4}\{random folder 5}\{random filename 12}.dmp
  • %ProgramData%\{random folder}\{random folder 4}\{random folder 5}.dmp
  • %ProgramData%\{random folder}\{random folder 4}\{random folder 5}.drv
  • %ProgramData%\{random folder}\{random filename 7}

(Note: %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.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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.)

It creates the following folders:

  • %Application Data%\{random folder}
  • %ProgramData%\{random folder}

(Note: %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.. %ProgramData% is the Program Data folder, where it usually is C:\Program Files in Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData in 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.)

Autostart Technique

This file infector registers as a system service to ensure its automatic execution at every system startup by adding the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{random}
ImagePath = "%Application Data%\{random folder}\[random filename 2}.exe"

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\
services\{random}
ObjectName = "LocalSystem"

Other System Modifications

This file infector adds the following registry keys:

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\AppCompat

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\AppCompat

HKEY_USERS\{SID}\{random key}

It adds the following registry entries:

HKEY_USERS\{SID}\{random key}\
shell\open\command
(Default) = "%Application Data%\{random folder}\[random filename 2}.exe" /START "%1" %*

HKEY_USERS\{SID}\{random key}\
shell\open\command
IsolatedCommand = "%Application Data%\{random folder}\[random filename 2}.exe" /START "%1" %*

HKEY_USERS\{SID}\{random key}\
shell\runas\command
(Default) = "%Application Data%\{random folder}\[random filename 2}.exe" /RUNAS /START "%1" %*

HKEY_USERS\{SID}\{random key}\
shell\runas\command
IsolatedCommand = "%Application Data%\{random folder}\[random filename 2}.exe" /RUNAS /START "%1" %*

HKEY_CURRENT_USER\Software\Policies\
Microsoft\Windows\AppCompat
DisablePCA = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\
Microsoft\Windows\AppCompat
DisablePCA = "1"

Other Details

This file infector connects to the following possibly malicious URL:

  • http://{BLOCKED}bi.ddns.net/si.php?xd={data}
  • http://{BLOCKED}eki.ddns.net/si.php?xd={data}
  • http://{BLOCKED}leulp.ddns.net/si.php?xd={data}
  • http://{BLOCKED}itogos.ddns.net/si.php?xd={data}
  • http://{BLOCKED}esb.ddns.net/si.php?xd={data}
  • http://{BLOCKED}enk.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ruohifx.ddns.net/si.php?xd={data}
  • http://{BLOCKED}le.ddns.net/si.php?xd={data}
  • http://{BLOCKED}aqhou.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ceduuc.ddns.net/si.php?xd={data}
  • http://{BLOCKED}om.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ow.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ahecpi.ddns.net/si.php?xd={data}
  • http://{BLOCKED}of.ddns.net/si.php?xd={data}
  • http://{BLOCKED}mopefuimu.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ar.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ucxealt.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ged.ddns.net/si.php?xd={data}
  • http://{BLOCKED}erfem.ddns.net/si.php?xd={data}
  • http://{BLOCKED}acfaosoc.ddns.net/si.php?xd={data}
  • http://{BLOCKED}dea.ddns.net/si.php?xd={data}
  • http://{BLOCKED}opfod.ddns.net/si.php?xd={data}
  • http://{BLOCKED}veicroen.ddns.net/si.php?xd={data}
  • http://{BLOCKED}xureaktex.ddns.net/si.php?xd={data}
  • http://{BLOCKED}xeoriqx.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ala.ddns.net/si.php?xd={data}
  • http://{BLOCKED}tido.ddns.net/si.php?xd={data}
  • http://{BLOCKED}uxo.ddns.net/si.php?xd={data}
  • http://{BLOCKED}riqib.ddns.net/si.php?xd={data}
  • http://{BLOCKED}lulesab.ddns.net/si.php?xd={data}
  • http://{BLOCKED}etx.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ibapweefe.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ihe.ddns.net/si.php?xd={data}
  • http://{BLOCKED}uxnu.ddns.net/si.php?xd={data}
  • http://{BLOCKED}otm.ddns.net/si.php?xd={data}
  • http://{BLOCKED}al.ddns.net/si.php?xd={data}
  • http://{BLOCKED}osweub.ddns.net/si.php?xd={data}
  • http://{BLOCKED}iximloir.ddns.net/si.php?xd={data}
  • http://{BLOCKED}xaosena.ddns.net/si.php?xd={data}
  • http://{BLOCKED}urveapi.ddns.net/si.php?xd={data}
  • http://{BLOCKED}fe.ddns.net/si.php?xd={data}
  • http://{BLOCKED}olpo.ddns.net/si.php?xd={data}
  • http://{BLOCKED}olpo.ddns.net/si.php?xd={data}
  • http://{BLOCKED}la.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ovv.ddns.net/si.php?xd={data}
  • http://{BLOCKED}owfanui.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ilfomu.ddns.net/si.php?xd={data}
  • http://{BLOCKED}amw.ddns.net/si.php?xd={data}
  • http://{BLOCKED}fopeugb.ddns.net/si.php?xd={data}
  • http://{BLOCKED}lea.ddns.net/si.php?xd={data}
  • http://{BLOCKED}liadgosee.ddns.net/si.php?xd={data}
  • http://{BLOCKED}otlus.ddns.net/si.php?xd={data}
  • http://{BLOCKED}akneecleo.ddns.net/si.php?xd={data}
  • http://{BLOCKED}feq.ddns.net/si.php?xd={data}
  • http://{BLOCKED}overhuonb.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ipofop.ddns.net/si.php?xd={data}
  • http://{BLOCKED}vohapi.ddns.net/si.php?xd={data}
  • http://{BLOCKED}qerew.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ikho.ddns.net/si.php?xd={data}
  • http://{BLOCKED}taucifm.ddns.net/si.php?xd={data}
  • http://{BLOCKED}ewsuas.ddns.net/si.php?xd={data}
  • http://{BLOCKED}okwaiqp.ddns.net/si.php?xd={data}
  • http://{BLOCKED}afxiewqee.ddns.net/si.php?xd={data}
  • http://{BLOCKED}axofwefut.ddns.net/si.php?xd={data}
  • http://{BLOCKED}di.ddns.net/si.php?xd={data}
  • http://{BLOCKED}upmtw5b2xx.onion/si.php?xd={data}

NOTES:

This malware infects files found in all removable and network drives to propagate to other system.

  SOLUTION

Minimum Scan Engine: 9.750
FIRST VSAPI PATTERN FILE: 11.640.02
FIRST VSAPI PATTERN DATE: 30 Apr 2015
VSAPI OPR PATTERN File: 11.641.00
VSAPI OPR PATTERN Date: 01 May 2015

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

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.
  • %Application Data%\{random folder}
  • %ProgramData%\{random folder}

Step 5

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\ControlSet001\services
    • {random}
  • In HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows
    • AppCompat
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows
    • AppCompat
  • In HKEY_USERS\{SID}
    • {random key}

Step 6

Restart in normal mode and scan your computer with your Trend Micro product for files detected as PE_MEWSPY.A-O. 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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