➔
search
✕

WORM_INSTYLER.AA

October 13, 2012
 ALIASES:

Hacktool (Symantec); ARC:Instyler, PAK:[5972932.INS]:Molebox, PAK:[5972932.INS]:UPX, [5972932.INS]:Backdoor.Win32.mIRC-ba (Kaspersky); Trojan.Win32.Generic!BT (Sunbelt); Backdoor.Bot.100628 (FSecure)

 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:

1,858,528 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

24 Jun 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.

Autostart Technique

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

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
WinXPService = "%Program Files%\k4v.pif"

Other System Modifications

This worm deletes the following files:

  • %Program Files%\password.val

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

It adds the following registry keys:

HKEY_CURRENT_USER\Software\mIRC

HKEY_LOCAL_MACHINE\Software\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC

HKEY_CLASSES_ROOT\.cha

HKEY_CLASSES_ROOT\.chat

HKEY_CLASSES_ROOT\ChatFile

HKEY_CLASSES_ROOT\ChatFile\DefaultIcon

HKEY_CLASSES_ROOT\ChatFile\Shell\
open\command

HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec

HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\Application

HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\ifexec

HKEY_CLASSES_ROOT\ChatFile\Shell\
open\ddeexec\Topic

HKEY_LOCAL_MACHINE\Software\Classes\
irc

HKEY_LOCAL_MACHINE\Software\Classes\
irc\DefaultIcon

HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
command

HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec

HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\Application

HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\ifexec

HKEY_LOCAL_MACHINE\Software\Classes\
irc\Shell\open\
ddeexec\Topic

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent

It adds the following registry entries:

HKEY_CURRENT_USER\Software\mIRC
DateUsed = "1326477047"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC
DisplayName = "mIRC"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Uninstall\
mIRC
UninstallString = "%Program Files%\k4v.pif -uninstall"

HKEY_LOCAL_MACHINE\SOFTWARE\Classes\
irc
EditFlags = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
VoiceEnabled = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseVoiceTips = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
KeyHoldHotKey = "91"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseBeepSRPrompt = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SRTimerDelay = "7d"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SRModeID = "{random values}"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
EnableSpeaking = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseBalloon = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseCharacterFont = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
UseSoundEffects = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
SpeakingSpeed = "5"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetX = "f423f"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetY = "f423f"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetWidth = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetHeight = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
PropertySheetPage = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowLeft = "ffffffff"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowTop = "ffffffff"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowWidth = "c8"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowHeight = "c8"

HKEY_CURRENT_USER\Software\Microsoft\
Microsoft Agent
CommandsWindowLocationSet = "0"

Dropping Routine

This worm drops the following files:

  • %Program Files%\0313.INS
  • %Program Files%\86102025.INS
  • %Program Files%\27296716.INS
  • %Program Files%\31861617.INS
  • %Program Files%\37224256.INS
  • %Program Files%\8204747.INS
  • %Program Files%\7058408.INS
  • %Program Files%\91723679.INS
  • %Program Files%\77463279.INS
  • %Program Files%\69768441.INS
  • %Program Files%\71793066.INS
  • %Program Files%\16263294.INS
  • %Program Files%\46602466.INS
  • %Program Files%\82562790.INS
  • %Program Files%\48171491.INS
  • %Program Files%\87432872.INS
  • %Program Files%\77279764.INS
  • %Program Files%\49258879.INS
  • %Program Files%\8272202.INS
  • %Program Files%\e21.reg
  • %Program Files%\w97.reg
  • %Program Files%\a5p63.msp

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

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

Restart in Safe Mode

[ Learn More ]

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_CURRENT_USER\Software
    • mIRC
  • In HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall
    • mIRC
  • In HKEY_CLASSES_ROOT
    • .cha
  • In HKEY_CLASSES_ROOT
    • .chat
  • In HKEY_CLASSES_ROOT
    • ChatFile
  • In HKEY_CLASSES_ROOT\ChatFile
    • DefaultIcon
  • In HKEY_CLASSES_ROOT\ChatFile\Shell\open
    • command
  • In HKEY_CLASSES_ROOT\ChatFile\Shell\open
    • ddeexec
  • In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
    • Application
  • In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
    • ifexec
  • In HKEY_CLASSES_ROOT\ChatFile\Shell\open\ddeexec
    • Topic
  • In HKEY_LOCAL_MACHINE\Software\Classes
    • irc
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc
    • DefaultIcon
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open
    • command
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open
    • ddeexec
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
    • Application
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
    • ifexec
  • In HKEY_LOCAL_MACHINE\Software\Classes\irc\Shell\open\ddeexec
    • Topic
  • In HKEY_CURRENT_USER\Software\Microsoft
    • Microsoft Agent

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\Run
    • WinXPService = "%Program Files%\k4v.pif"
  • In HKEY_CURRENT_USER\Software\mIRC
    • DateUsed = "1326477047"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\mIRC
    • DisplayName = "mIRC"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\mIRC
    • UninstallString = "%Program Files%\k4v.pif -uninstall"
  • In HKEY_LOCAL_MACHINE\SOFTWARE\Classes\irc
    • EditFlags = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • VoiceEnabled = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • UseVoiceTips = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • KeyHoldHotKey = "91"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • UseBeepSRPrompt = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • SRTimerDelay = "7d"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • SRModeID = "{random values}"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • EnableSpeaking = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • UseBalloon = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • UseCharacterFont = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • UseSoundEffects = "1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • SpeakingSpeed = "5"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • PropertySheetX = "f423f"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • PropertySheetY = "f423f"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • PropertySheetWidth = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • PropertySheetHeight = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • PropertySheetPage = "0"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • CommandsWindowLeft = "ffffffff"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • CommandsWindowTop = "ffffffff"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • CommandsWindowWidth = "c8"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • CommandsWindowHeight = "c8"
  • In HKEY_CURRENT_USER\Software\Microsoft\Microsoft Agent
    • CommandsWindowLocationSet = "0"

Step 5

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.
  • %Program Files%\0313.INS
  • %Program Files%\86102025.INS
  • %Program Files%\27296716.INS
  • %Program Files%\31861617.INS
  • %Program Files%\37224256.INS
  • %Program Files%\8204747.INS
  • %Program Files%\7058408.INS
  • %Program Files%\91723679.INS
  • %Program Files%\77463279.INS
  • %Program Files%\69768441.INS
  • %Program Files%\71793066.INS
  • %Program Files%\16263294.INS
  • %Program Files%\46602466.INS
  • %Program Files%\82562790.INS
  • %Program Files%\48171491.INS
  • %Program Files%\87432872.INS
  • %Program Files%\77279764.INS
  • %Program Files%\49258879.INS
  • %Program Files%\8272202.INS
  • %Program Files%\e21.reg
  • %Program Files%\w97.reg
  • %Program Files%\a5p63.msp

Step 6

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

Step 7

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.

  • %Program Files%\password.val


Did this description help? Tell us how we did.