TROJ_FAKEAV.GRO

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.

It connects to certain URLs. It may do this to remotely inform a malicious user of its installation. It may also do this to download possibly malicious files onto the computer, which puts the computer at a greater risk of infection by other threats.

It deletes the initially executed copy of itself.

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 and executes them:

• %System Root%\Documents and Settings\All Users\Application Data\{random name}.exe

(Note: %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.)

It drops the following files:

• %Desktop%\System Check.lnk
• %Start Menu%\Programs\System Check\System Check.lnk
• %Start Menu%\Programs\System Check\Uninstall System Check.lnk
• %System Root%\Documents and Settings\All Users\Application Data\{random name}
• %User Profile%\Application Data\Microsoft\Internet Explorer\Quick Launch\System Check.lnk

(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.. %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.. %System Root% is the root folder, which is usually C:\. It is also where the operating system is located.. %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.)

It creates the following folders:

• %Start Menu%\Programs\System Check

(Note: %Start Menu% is the current user's Start Menu folder, which is usually C:\Windows\Profiles\{user name}\Start Menu on Windows 98 and ME, C:\WINNT\Profiles\{user name}\Start Menu on Windows NT and C:\Windows\Start Menu or C:\Documents and Settings\{User name}\Start Menu on Windows 2000, XP, and Server 2003.)

Other System Modifications

This Trojan adds the following registry entries as part of its installation routine:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Main
Use FormSuggest = "Yes"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnOnZoneCrossing = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
WarnonBadCertRecving = "0"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings
CertificateRevocation = "0"

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Internet Settings\
Zones\3
1601 = "0"

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\WinTrust\
Trust Providers\Software Publishing
State = "23e00"

(Note: The default value data of the said registry entry is 23c00.)

Download Routine

This Trojan connects to the following malicious URLs:

• {BLOCKED}.{BLOCKED}.13.19
• {BLOCKED}ward.com
• {BLOCKED}ward.com/britix/a
• {BLOCKED}ward.com/britix/ar
• {BLOCKED}ward.com/up.php?0Q9oBPXEN0uECUgzEJ95RQsajjnvq1aG3F/2q5oNvBGAyHya0iCkBIHoIxsgj7n41ezh
• {BLOCKED}sprin.com
• {BLOCKED}locen.com
• {BLOCKED}locen.com/britix/a
• {BLOCKED}locen.com/customers/buy.php?pid=DEFRAG_ADV_BASIC&id=543&subid=01&guid=333470043334410233344203&version_name=System%20Check
• {BLOCKED}redir.com

Other Details

This Trojan deletes the initially executed copy of itself