TROJ_FAKEAV.NBE

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 modifies the Internet Explorer Zone Settings.

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

(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.)

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

Other System Modifications

This Trojan adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\{random name}

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\{random name}\
DEBUG

It adds the following registry entries:

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"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Associations
LowRiskFileTypes = ".zip;.rar;.nfo;.txt;.exe;.bat;.com;.cmd;.reg;.msi;.htm;.html;.gif;.bmp;.jpg;.avi;.mpg;.mpeg;.mov;.mp3;.m3u;.wav;.scr;"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Attachments
SaveZoneInformation = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
ESENT\Process\{random name}\
DEBUG
Trace Level = ""

It modifies the following registry entries:

HKEY_CURRENT_USER\Software\Microsoft\
Internet Explorer\Download
CheckExeSignatures = "No"

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

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.)

Web Browser Home Page and Search Page Modification

This Trojan modifies the Internet Explorer Zone Settings.

Download Routine

This Trojan connects to the following malicious URLs:

• {BLOCKED}coomerc.com
• {BLOCKED}ingona.com
• {BLOCKED}isful.com
• {BLOCKED}esier.com
• {BLOCKED}retin.com
• {BLOCKED}truct.com

Other Details

This Trojan deletes the initially executed copy of itself