XCan

This page shows details and results of our analysis on the malware XCan

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Threat Detail

Malware Type: Trojan

Malware Sub-type: N/A

Discovery Date: 2002-09-03

Next Steps:

Overview
Characteristics
Symptoms
Method of Infection
Removal

Overview

This is a trojan detection. Unlike viruses, trojans do not self-replicate. They are spread manually, often under the premise that they are beneficial or wanted. The most common installation methods involve system or security exploitation, and unsuspecting users manually executing unknown programs. Distribution channels include email, malicious or hacked web pages, Internet Relay Chat (IRC), peer-to-peer networks, etc.

Minimum DAT

4222 (2002-09-11)

Updated DAT

4233 (2002-11-13)

Minimum Engine

5400.1158

File Length

61,440 bytes

Description Added

2002-09-16

Description Modified

2002-09-16

Malware Proliferation

Characteristics

This trojan makes extensive registry changes so that the trojan file will run rather than the default application for viewing the affected file-types.

The old Default data for the registry entries below are saved by the trojan in a new value named "SysBack".

HKEY_CLASSES_ROOT\avifile\shell\open\command

HKEY_CLASSES_ROOT\batfile\shell\open\command

HKEY_CLASSES_ROOT\chm.file\shell\open\command

HKEY_CLASSES_ROOT\Excel.Sheet.8\shell\Open\command

HKEY_CLASSES_ROOT\giffile\shell\open\command

HKEY_CLASSES_ROOT\hlpfile\shell\open\command

HKEY_CLASSES_ROOT\htmlfile\shell\open\command

HKEY_CLASSES_ROOT\inffile\shell\open\command

HKEY_CLASSES_ROOT\inifile\shell\open\command

HKEY_CLASSES_ROOT\jpegfile\shell\open\command

HKEY_CLASSES_ROOT\midfile\shell\open\command

HKEY_CLASSES_ROOT\mp3file\shell\open\command

HKEY_CLASSES_ROOT\regfile\shell\open\command

HKEY_CLASSES_ROOT\SoundRec\shell\open\command

HKEY_CLASSES_ROOT\txtfile\shell\open\command

HKEY_CLASSES_ROOT\WinZip\shell\open\command

HKEY_CLASSES_ROOT\Word.Document.8\shell\Open\command

HKEY_CLASSES_ROOT\Word.RTF.8\shell\Open\command

The new Default data is changed to point to the trojan:

"(Default)" = %SysDir%\system.exe %1 %*

Another registry entry is created to run the trojan at startup:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run_
"LoadDesktop" = C:\WINDOWS\SYSTEM\system.exe

The trojan also copies itself to the following locations:

%WinDir%\loadexe.exe

%SysDir%\system.exe

%WinDir%\TEMP\fonts.exe

The version information in the files' properties is used to make it appear to be a valid applicaton:

Company Name: xcan
Internal Name: system
Product Name: Explorer

Symptoms

Presence of the following files:

Opening of the file-types referenced in the registry entries above will cease to function

Method of Infection

The trojan infects a system upon execution by copying itself to the System directory and hooking the Registry to run at system startup.

Removal

All Users:
Use current engine and DAT files for detection and removal.

Modifications made to the system Registry and/or INI files for the purposes of hooking system startup, will be successfully removed if cleaning with the recommended engine and DAT combination (or higher).

But in some particular cases, the following steps need to be taken.

Please go to the Microsoft Recovery Console and restore a clean MBR.

On Windows XP:

Insert the Windows XP CD into the CD-ROM drive and restart the computer.
When the "Welcome to Setup" screen appears, press R to start the Recovery Console.
Select the Windows installation that is compromised and provide the administrator password.
Issue 'fixmbr' command to restore the Master Boot Record
Follow onscreen instructions.
Reset and remove the CD from CD-ROM drive.

On Windows Vista and 7:

Insert the Windows CD into the CD-ROM drive and restart the computer.
Click on "Repair Your Computer".
When the System Recovery Options dialog comes up, choose the Command Prompt.
Issue 'bootrec /fixmbr' command to restore the Master Boot Record.
Follow onscreen instructions.
Reset and remove the CD from CD-ROM drive.