TROJ_AUTOIT.VI
Trojan:Win32/Sisron (Microsoft); W32/YahLover.worm!j (McAfee); W32.Imaut (Symantec); PAK:UPX, ARC:Embedded (Kaspersky); Trojan.Win32.AutoIt.gen.1 (v) (Sunbelt); Trojan.Autoit.Agent.Z (FSecure)
Windows 2000, Windows XP, Windows Server 2003
![](/vinfo/imgFiles/legend.jpg)
Threat Type: Trojan
Destructiveness: No
Encrypted:
In the wild: Yes
OVERVIEW
This Trojan 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
Arrival Details
This Trojan 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 Trojan drops the following copies of itself into the affected system:
- %System%\chromechrist.exe
- %Windows%\chromechrist.exe
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.. %Windows% is the Windows folder, which is usually C:\Windows or C:\WINNT.)
Autostart Technique
This Trojan adds the following registry entries to enable its automatic execution at every system startup:
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
Chrome3 = "%System%\chromechrist.exe"
HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
google = "http://www.{BLOCKED}10.com "
It 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 chromechrist.exe"
(Note: The default value data of the said registry entry is Explorer.exe.)
Other System Modifications
This Trojan adds the following registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes
HKEY_CURRENT_USER\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes
It adds the following registry entries:
HKEY_CURRENT_USER\Software\Microsoft\
Search Assistant
DefaultSearchURL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\SearchScopes
URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search={searchTerms}"
HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\SearchScopes
URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search={searchTerms}"
It modifies the following registry entries:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Page_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Default_Search_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Internet Explorer\Main
Search Page = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
(Note: The default value data of the said registry entry is http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch.)
Dropping Routine
This Trojan drops the following files:
- %Desktop%\Search here.lnk
- %Desktop%\Make friends.lnk
- %Favorites%\Sioril.lnk
- %User Startup%\Search bar.lnk
- %User Profile%\My Documents\Search bar.lnk
- %User Profile%\Quick Launch\Search.lnk
- %Desktop%\Toolbar.exe
- %Desktop%\sioril.gadget
(Note: %Desktop% is the current user's desktop, which is usually C:\Windows\Profiles\{user name}\Desktop on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Desktop on Windows NT, and C:\Documents and Settings\{User Name}\Desktop on Windows 2000, XP, and Server 2003.. %Favorites% is the current user's Favorites folder, which is usually C:\Windows\Favorites on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Favorites on Windows NT, and C:\Documents and Settings\{user name}\Favorites on Windows 2000, XP, and Server 2003.. %User Startup% is the current user's Startup folder, which is usually C:\Windows\Profiles\{user name}\Start Menu\Programs\Startup on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu\Programs\Startup on Windows NT, and C:\Documents and Settings\{User name}\Start Menu\Programs\Startup.. %User Profile% is the current user's profile folder, which is usually C:\Windows\Profiles\{user name} on Windows 98 and ME, C:\WINNT\Profiles\{user name} on Windows NT, and C:\Documents and Settings\{user name} on Windows 2000, XP, and Server 2003.)
Other Details
This Trojan connects to the following possibly malicious URL:
- http://toolbar99999.{BLOCKED}3.amazonaws.com/toolbar.zip
- http://sioriltoolbar.{BLOCKED}3.amazonaws.com/sioril.gadget
This report is generated via an automated analysis system.
SOLUTION
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 TROJ_AUTOIT.VI using either the Startup Disk or Recovery Console
Step 3
Delete this registry key
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\Internet Explorer
- SearchScopes
- In HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer
- SearchScopes
Step 4
Delete this registry value
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
- Chrome3 = "%System%\chromechrist.exe"
- In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
- google = "http://www.{BLOCKED}10.com "
- In HKEY_CURRENT_USER\Software\Microsoft\Search Assistant
- DefaultSearchURL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\SearchScopes
- URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search={searchTerms}"
- In HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\SearchScopes
- URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search={searchTerms}"
Step 5
Restore this modified registry value
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\Internet Explorer\Main
- From: Default_Page_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
To: Default_Page_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&pver=6&ar=msnhome""
- From: Default_Page_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
- From: Default_Search_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
To: Default_Search_URL = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
- From: Default_Search_URL = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main
- From: Search Page = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
To: Search Page = ""http://www.microsoft.com/isapi/redir.dll?prd=ie&ar=iesearch""
- From: Search Page = "http://www.{BLOCKED}l.co.uk/index.php?page=search/web&search="
- In HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
- From: Shell = "Explorer.exe chromechrist.exe"
To: Shell = ""Explorer.exe""
- From: Shell = "Explorer.exe chromechrist.exe"
Step 6
Search and delete these files
- %Desktop%\Search here.lnk
- %Desktop%\Make friends.lnk
- %Favorites%\Sioril.lnk
- %User Startup%\Search bar.lnk
- %User Profile%\My Documents\Search bar.lnk
- %User Profile%\Quick Launch\Search.lnk
- %Desktop%\Toolbar.exe
- %Desktop%\sioril.gadget
Step 7
Scan your computer with your Trend Micro product to delete files detected as TROJ_AUTOIT.VI. 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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