WORM_HILGIL.SMRP

April 16, 2015
 Analysis by: Adrian Cofreros
 PLATFORM:

Windows

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

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

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

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

286,720 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

07 Mar 2014

Arrival Details

This worm 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 worm drops the following copies of itself into the affected system and executes them:

  • %All Users Profile%\Application Data\wmimgmt.exe
  • %All Users Profile%\wmimgmt.exe - if cant create the first one

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

It drops the following files:

  • %All Users Profile%\DRM\Media\B13A4DC0.db -windows xp
  • %All Users Profile%\DRM\Media\line.dat - windows xp
  • %Temporary Internet Files%\drivers.p
  • %Temporary Internet Files%\tmp~ghi.log
  • %User Temp%\temp.vih
  • %System Root%\Users\Public\Documents\Media\9D26B837.db -windows 7

(Note: %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.. %Temporary Internet Files% is the Temporary Internet Files folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temporary Internet Files on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Microsoft\Windows\Temporary Internet Files on Windows Vista (32- and 64-bit), Windows 7 (32- and 64-bit), and Windows Server 2008; C:\Users\{user name}\AppData\Local\Microsoft\Windows\INetCache on Windows 8 (32- and 64-bit), Windows 8.1 (32- and 64-bit), and Windows Server 2012.. %User Temp% is the user's temporary folder, where it usually is C:\Documents and Settings\{user name}\Local Settings\Temp on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\Users\{user name}\AppData\Local\Temp 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.. %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.)

It creates the following folders:

  • %System Root%\Users\Public\Documents\Media -windows 7
  • %All Users Profile%\DRM\Media\

(Note: %System Root% is the Windows root folder, where it usually is C:\ on all Windows operating system versions.. %All Users Profile% is the All Users folder, where it usually is C:\Documents and Settings\All Users on Windows 2000, Windows Server 2003, and Windows XP (32- and 64-bit); C:\ProgramData 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.)

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
wmi32 = "%All Users Profile%\Application Data\wmimgmt.exe"

Other System Modifications

This worm adds the following registry entries:

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
exefile
NeverShowExt = ""

HKEY_CLASSES_ROOT\exefile
NeverShowExt = ""

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced\Folder\SuperHidden
UncheckedValue = "0"

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

Propagation

This worm creates the following folders in all removable drives:

  • {removable drive letter}:\RECYCLER

It drops copies of itself in network drives such as the following:

  • {network drive letter}:\RECYCLER\wmimgmt.com

It drops the following copy(ies) of itself in all removable drives:

  • {removable drive letter}:\RECYCLER\wmimgmt.com

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

NOTES:

It hides the folder it finds and drops a copy of itself using the folder names on the affected drive (removable, network):

  • {folder name}.exe

It creates the following folder in the network drive:

  • {network drive letter}:\RECYCLER

It drops the following file in network and removable drive:

  • {network drive letter}:\RECYCLER\desktop.ini
  • {removable drive letter}:\RECYCLER\desktop.ini

  SOLUTION

Minimum Scan Engine:

9.700

FIRST VSAPI PATTERN FILE:

10.648.05

FIRST VSAPI PATTERN DATE:

07 Mar 2014

VSAPI OPR PATTERN File:

10.649.00

VSAPI OPR PATTERN Date:

08 Mar 2014

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

Scan your computer with your Trend Micro product and note files detected as WORM_HILGIL.SMRP

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_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
    • wmi32 = "%All Users Profile%\Application Data\wmimgmt.exe"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\exefile
    • NeverShowExt = ""
  • In HKEY_CLASSES_ROOT\exefile
    • NeverShowExt = ""

Step 5

Restore this modified 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\Explorer\Advanced
    • From: ShowSuperHidden = "0"
      To: ShowSuperHidden = "1"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\SuperHidden
    • From: UncheckedValue = "0"
      To: UncheckedValue = "1"

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.
  • %System Root%\Users\Public\Documents\Media
  • %All Users Profile%\DRM\Media
  • {network drive letter}:\RECYCLER
  • {removable drive letter}:\RECYCLER

Step 7

Search and delete these files

[ Learn More ]
There may be some component 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.
  • %Temporary Internet Files%\drivers.p
  • %Temporary Internet Files%\tmp~ghi.log
  • %User Temp%\temp.vih
  • {network drive letter}:\AuT

Step 8

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_HILGIL.SMRP. 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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