WORM_MALEX.SRY


 ALIASES:

Trojan:Win32/Malex.gen!E (Microsoft); BehavesLike.Win32.Malware.wlk (mx-v) (Sunbelt)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

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

  • 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.

  TECHNICAL DETAILS

File Size:

335,872 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

16 Oct 2012

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:

  • winlogons.exe
  • c\svchost1.exe
  • d\svchost2.exe
  • e\svchost3.exe
  • f\svchost4.exe
  • g\svchost5.exe
  • h\svchost6.exe
  • wins\svchost.exe

It creates the following folders:

  • c
  • d
  • e
  • f
  • g
  • h
  • wins
  • WinAxA

Autostart Technique

This worm modifies the following registry entries to ensure it automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows NT\CurrentVersion\Winlogon
shell = "Explorer.exe winlogons.exe"

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

Other System Modifications

This worm modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 2.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
HideFileExt = "1"

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

Dropping Routine

This worm drops the following files:

  • winlogons.exe
  • c\svchost1.exe
  • d\svchost2.exe
  • e\svchost3.exe
  • f\svchost4.exe
  • g\svchost5.exe
  • h\svchost6.exe
  • wins\svchost.exe
  • %Windows%\c\svchost1.exe
  • %Windows%\d\svchost2.exe
  • %Windows%\e\svchost3.exe
  • %Windows%\f\svchost4.exe
  • %Windows%\g\svchost5.exe
  • All Users.exe
  • Application Data.exe
  • Adobe.exe
  • Acrobat.exe
  • 10.0.exe
  • Replicate.exe
  • Security.exe
  • Setup.exe
  • {AC76BA86-7AD7-1033-7B44-AA0000000001}.exe
  • Microsoft.exe
  • Crypto.exe
  • DSS.exe
  • MachineKeys.exe
  • RSA.exe
  • S-1-5-18.exe
  • HTML Help.exe
  • Media Index.exe
  • Media Player.exe
  • Network.exe
  • Connections.exe
  • Cm.exe
  • Pbk.exe
  • User Account Pictures.exe
  • Default Pictures.exe
  • Desktop.exe
  • Documents.exe
  • My Music.exe
  • My Playlists.exe
  • Sample Music.exe
  • Sample Playlists.exe
  • 0008044E.exe
  • My Pictures.exe
  • Sample Pictures.exe
  • My Videos.exe
  • DRM.exe
  • Favorites.exe
  • Start Menu.exe
  • Programs.exe
  • Accessories.exe
  • Accessibility.exe
  • Communications.exe
  • Entertainment.exe
  • System Tools.exe
  • Administrative Tools.exe
  • Games.exe
  • Startup.exe
  • WinPcap.exe
  • Templates.exe
  • Default User.exe
  • Internet Explorer.exe
  • SystemCertificates.exe
  • My.exe
  • Certificates.exe
  • CRLs.exe
  • CTLs.exe
  • Cookies.exe
  • Local Settings.exe
  • Windows Media.exe
  • 9.0.exe
  • History.exe
  • History.IE5.exe
  • Temp.exe
  • Temporary Internet Files.exe
  • Content.IE5.exe
  • 09RWHJQN.exe
  • BVLBNMKH.exe
  • ZDGZNKA5.exe
  • ZSGKJKO6.exe
  • My Documents.exe
  • NetHood.exe
  • PrintHood.exe
  • Recent.exe
  • SendTo.exe
  • LocalService.exe
  • Credentials.exe
  • S-1-5-19.exe
  • Windows.exe
  • 246FT6TD.exe
  • 9STOYKO4.exe
  • NF72HY20.exe
  • PHOM4UYK.exe
  • NetworkService.exe
  • S-1-5-20.exe
  • Wilbert.exe
  • Identities.exe
  • {8A24C031-62FE-4BF5-94F0-BFD4FBCD674B}.exe
  • S-1-5-21-1645522239-1292428093-682003330-1003.exe
  • Quick Launch.exe
  • MMC.exe
  • Themes.exe
  • Links.exe
  • CD Burning.exe
  • Microsoft .NET Framework 4 Setup_4.0.30319.exe
  • Microsoft Visual C++ 2010 x86 Redistributable Setup_10.0.30319.exe

(Note: %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)

This report is generated via an automated analysis system.

  SOLUTION

Minimum Scan Engine:

9.200

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Identify and delete files detected as WORM_MALEX.SRY using either the Startup Disk or Recovery Console

[ Learn More ]

Step 3

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: Hidden = "2"
      To: Hidden = ""2""
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: HideFileExt = "1"
      To: HideFileExt = ""1""
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
    • From: shell = "Explorer.exe winlogons.exe"
      To: shell = ""Explorer.exe""

Step 4

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.
  • winlogons.exe
  • c\svchost1.exe
  • d\svchost2.exe
  • e\svchost3.exe
  • f\svchost4.exe
  • g\svchost5.exe
  • h\svchost6.exe
  • wins\svchost.exe
  • %Windows%\c\svchost1.exe
  • %Windows%\d\svchost2.exe
  • %Windows%\e\svchost3.exe
  • %Windows%\f\svchost4.exe
  • %Windows%\g\svchost5.exe
  • All Users.exe
  • Application Data.exe
  • Adobe.exe
  • Acrobat.exe
  • 10.0.exe
  • Replicate.exe
  • Security.exe
  • Setup.exe
  • {AC76BA86-7AD7-1033-7B44-AA0000000001}.exe
  • Microsoft.exe
  • Crypto.exe
  • DSS.exe
  • MachineKeys.exe
  • RSA.exe
  • S-1-5-18.exe
  • HTML Help.exe
  • Media Index.exe
  • Media Player.exe
  • Network.exe
  • Connections.exe
  • Cm.exe
  • Pbk.exe
  • User Account Pictures.exe
  • Default Pictures.exe
  • Desktop.exe
  • Documents.exe
  • My Music.exe
  • My Playlists.exe
  • Sample Music.exe
  • Sample Playlists.exe
  • 0008044E.exe
  • My Pictures.exe
  • Sample Pictures.exe
  • My Videos.exe
  • DRM.exe
  • Favorites.exe
  • Start Menu.exe
  • Programs.exe
  • Accessories.exe
  • Accessibility.exe
  • Communications.exe
  • Entertainment.exe
  • System Tools.exe
  • Administrative Tools.exe
  • Games.exe
  • Startup.exe
  • WinPcap.exe
  • Templates.exe
  • Default User.exe
  • Internet Explorer.exe
  • SystemCertificates.exe
  • My.exe
  • Certificates.exe
  • CRLs.exe
  • CTLs.exe
  • Cookies.exe
  • Local Settings.exe
  • Windows Media.exe
  • 9.0.exe
  • History.exe
  • History.IE5.exe
  • Temp.exe
  • Temporary Internet Files.exe
  • Content.IE5.exe
  • 09RWHJQN.exe
  • BVLBNMKH.exe
  • ZDGZNKA5.exe
  • ZSGKJKO6.exe
  • My Documents.exe
  • NetHood.exe
  • PrintHood.exe
  • Recent.exe
  • SendTo.exe
  • LocalService.exe
  • Credentials.exe
  • S-1-5-19.exe
  • Windows.exe
  • 246FT6TD.exe
  • 9STOYKO4.exe
  • NF72HY20.exe
  • PHOM4UYK.exe
  • NetworkService.exe
  • S-1-5-20.exe
  • Wilbert.exe
  • Identities.exe
  • {8A24C031-62FE-4BF5-94F0-BFD4FBCD674B}.exe
  • S-1-5-21-1645522239-1292428093-682003330-1003.exe
  • Quick Launch.exe
  • MMC.exe
  • Themes.exe
  • Links.exe
  • CD Burning.exe
  • Microsoft .NET Framework 4 Setup_4.0.30319.exe
  • Microsoft Visual C++ 2010 x86 Redistributable Setup_10.0.30319.exe

Step 5

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.
  • c
  • d
  • e
  • f
  • g
  • h
  • wins
  • WinAxA

Step 6

Scan your computer with your Trend Micro product to delete files detected as WORM_MALEX.SRY. 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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