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BackDoor-COK

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

Threat Detail

Malware Type: Trojan

Malware Sub-type: Remote Access

Discovery Date: 2005-02-24

Next Steps:

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

4433 (2005-02-24)

Updated DAT

4433 (2005-02-24)

 Minimum Engine

5.1.00

File Length

33,068

 Description Added

2005-02-24

Description Modified

2005-03-15

Malware Proliferation

Characteristics

This is a remote access trojan.

When run, it drops the following files in the system directory, typically:

  • C:\Windows\system32\spool.exe (45,056 bytes)
  • C:\Windows\system32\spool.dll (32,768 bytes)

The trojan runs the "spool.exe" file and registers as a windows service named "Logical Disk Manager Provider" with the comment "Manager the local hard disk and record the status of the disk".

The process "spool.exe" injects "spool.dll" into all processes in the victim's machine except for the following processes:

  • cl.exe
  • conime.exe
  • csrss.exe
  • ctfmon.exe
  • lsass.exe
  • NOTEPAD.EXE
  • rundll32.exe
  • services.exe
  • smss.exe
  • spool.exe
  • svchost.exe
  • winlogon.exe
  • WINWORD.EXE

The trojan scans and monitors files with the extensions ".doc", ".ppt", and ".xls". It then creates the file named "C:\WINDOWS\system32\sysinfo2033043~1.info" and writes the network interface information of the victim's machine. It also drops a list of the remote url to a text file named "C:\WINDOWS\system32\srvchost.dll"

The trojan sends the notification to the author via htttp using a url list. Then it connects to the remote sites and waits for commands, including download/upload files, and send the file information.

Symptoms

  • Existence of files mentioned above.

Method of Infection

Trojans do not self-replicate. They are spread manually, often under the premise that the executable is something beneficial. Distribution channels include IRC, peer-to-peer networks, newsgroup postings, email, etc.

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.

Variants

United States - English