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Downloader-AAZ

This page shows details and results of our analysis on the malware Downloader-AAZ

Threat Detail

Malware Type: Trojan

Malware Sub-type: Downloader

Discovery Date: 2005-05-21

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

4497 (2005-05-23)

Updated DAT

4498 (2005-05-24)

 Minimum Engine

5.1.00

File Length

53,248 bytes

 Description Added

2005-05-21

Description Modified

2005-05-21

Malware Proliferation

Characteristics

This trojan simply attempts to connect to a remote FTP server to download and execute a file. The FTP server is reference by IP number (rather than a DNS name).  At the time of this writing, the file download was a new trojan installer, detected as MultiDropper-AV with DAT files going back four years ago.  This new variant of MultiDropper-AV installs a new keylogger trojan (Keylog-LPK).

Symptoms

- Unexpected outbound FTP connection
- Firewall program alerting that application is attempting to access the Interent

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:
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