TROJ_FAKEAV.FMS

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 employs registry shell spawning by adding certain registry entries. This allows this malware to execute even when other applications are opened.

It modifies certain registry entries to disable Security Center functions. Doing this allows this malware to execute its routines without being detected.

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:

• %Application Data%\{random three letters}.exe

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

It drops the following files:

• %System Root%\Documents and Settings\All Users\Application Data\4e0b8f8f
• %User Profile%\Application Data\eb1beb3f
• %Application Data%\ebda722c
• %User Profile%\Templates\e8662524

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

Autostart Technique

This Trojan employs registry shell spawning to ensure its execution when certain file types are accessed by adding the following entries:

HKEY_CLASSES_ROOT\mdaw\shell\
open\command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"

HKEY_CURRENT_USER\Software\Classes\
.exe
{default} = "mdaw"

HKEY_CURRENT_USER\Software\Classes\
mdaw\shell\open\
command
{default} = ""%Application Data%\{random three letters}.exe" -a "%1" %*"

Other System Modifications

This Trojan modifies the following registry key(s)/entry(ies) as part of its installation routine:

HKEY_CLASSES_ROOT\.exe
{default} = "mdaw"

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

It adds the following registry keys as part of its installation routine:

HKEY_CLASSES_ROOT\mdaw

HKEY_CURRENT_USER\Software\Classes\
.exe

HKEY_CURRENT_USER\Software\Classes\
mdaw

It modifies the following registry entries to disable Security Center functions:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusDisableNotify = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallDisableNotify = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
UpdatesDisableNotify = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
AntiVirusOverride = "1"

(Note: The default value data of the said registry entry is 0.)

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Security Center
FirewallOverride = "1"

(Note: The default value data of the said registry entry is 0.)

Other Details

This Trojan connects to the following possibly malicious URL:

• http://{BLOCKED}.com
• http://{BLOCKED}.com
• http://{BLOCKED}.com
• http://{BLOCKED}.com

It deletes the initially executed copy of itself