TSPY_CITADEL.FLO

This spyware arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It is injected into all running processes to remain memory resident.

It modifies Internet Explorer security settings. This puts the affected computer at greater risk, as it allows malicious URLs to be accessed by the computer.

However, as of this writing, the said sites are inaccessible.

Arrival Details

This spyware 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 spyware drops the following files:

• %Application Data%\{random folder 2}\{random file name 2}.{random extension name}
• %Application Data%\{random folder 3}\{random file name 3}.{random extension name}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It drops the following copies of itself into the affected system:

• %Application Data%\{random folder 1}\{random file name 1}.exe

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It creates the following folders:

• %Application Data%\{random folder 1}
• %Application Data%\{random folder 2}
• %Application Data%\{random folder 3}

(Note: %Application Data% is the current user's Application Data folder, which is usually C:\Documents and Settings\{user name}\Application Data on Windows 2000, XP, and Server 2003, or C:\Users\{user name}\AppData\Roaming on Windows Vista and 7.)

It is injected into all running processes to remain memory resident.

Autostart Technique

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

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Run
{random} = "%Application Data%\{random folder 1}\{random file name 1}.exe"

Other System Modifications

This spyware adds the following registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
{random key}

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Windows%\explorer.exe = "%Windows%\explorer.exe:*:Enabled:Windows Explorer"

Web Browser Home Page and Search Page Modification

This spyware modifies Internet Explorer zone settings.

Download Routine

This spyware connects to the following URL(s) to download its configuration file:

• http://{BLOCKED}.{BLOCKED}.177.125/tr2102/file.php

Other Details

However, as of this writing, the said sites are inaccessible.

NOTES:

The configuration file may contain URLs where it downloads an updated copy of itself and where it sends its gathered information.

It may also contain URLs of its target online banking and finance-related sites from where it steals the information. Note that the contents of the file, hence the list of websites to monitor, may change anytime.

It may also gather the following information from the affected system:

• Data stored in cookie files (URLs)
• Email-related information such as account names, email addresses, passwords, server data, and server port
• Email information stored in the user's Windows Address Book (WAB) file