BackDoor-CYL

This page shows details and results of our analysis on the malware BackDoor-CYL

Download Current DAT: 6617

Threat Detail

Malware Type: Trojan

Malware Sub-type: Remote Access

Discovery Date: 2006-03-23

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

4725 (2006-03-23)

Updated DAT

4918 (2006-12-13)

Minimum Engine

5.1.00

File Length

N/A

Description Added

2006-03-23

Description Modified

2006-03-24

Malware Proliferation

Characteristics

The main installer drops a DLL file and injects the DLL into Explorer.exe memory. This results in Explorer.exe listening on a random TCP port for commands.

System Changes

Files Added

%WINDIR% \system\svchost.exe
%WINDIR% \system\svchost.dll ( 35328 bytes )

Registry

The following registry keys are created:

hkey_local_machine\software\microsoft\windows\currentversion
\shellbot
\adrress="b1"
controller_backup="(binary registry data)
controller="(binary registry data)
version="variable"
id="variable id"
delay="variable"
conn_limit="variable"
white_ip_id="variable"
hkey_local_machine\software\microsoft\windows\currentversion\run
\windowsupdate="%WINDIR% \System\svchost.exe /s"

Server Component:

When the server component (svchost.dll) is executed, it connects to following IP addresses awaiting commands from the attacker using the client component.

198.wwwsky[hidden] - TCP port: 1199
www.gifts[hidden]com: - TCP port: 1520

The trojan can download updated copies of itself from following IPs. Few of the links are down while few are still active at the time of writing this description.

216.255.1[hidden]
65.19.1[Hidden]
64.71.1[Hidden]
64.182.2[hidden]
87.249.3[hidden]
67.18.1[hidden]
64.191.8[hidden]
209.160.7[hidden]
66.111.5[hidden]
64.182.2[hidden]
66.111.5[hidden]

Symptoms

Presence of the files mentioned above

Unexplained activity on the victim's machine indicative of someone having remote access via the client component

Method of Infection

Trojans do not self-replicate. They spread manually, often under the premise that the executable is something beneficial.

Trojans may also be received as a result of poor security practices, or un-patched machines and vulnerable systems.

Distribution channels include IRC, peer-to-peer networks, email, newsgroups postings, etc.

Removal

All Users:

Please use the following instructions for all supported versions of Windows to remove threats and other potential risks:

1.Disable System Restore .

2.Update to current engine and DAT files for detection and removal.

3.Run a complete system scan.

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).

1. 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.