Virus Profile: Downloader-ABA

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Virus Profile information details
Risk Assessment: Home Low | Corporate Low
Date Discovered: 5/24/2005
Date Added: 5/24/2005
Origin: Unknown
Length: N/A
Type: Trojan
Subtype: Downloader
DAT Required: 4498
Removal Instructions
   
 
 
   

Description

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.

Indication of Infection

Many of these Downloaders install other malware including viruses as well as other Trojans.

Additionally many of them are used to remotely install Adware packages onto the affected host machine for the purposes of gaining referral revenue from the Adware software vendor.

Please note: If Adware is installed via a Downloader it may install it "cleanly" with the relevant uninstaller included for the user to terminate this Adware, although frequently this is not the case.

Methods of Infection

N/A. Downloaders are not viruses, and as such do not themselves contain any method to replicate. However they may themselves be downloaded by other viruses and/or Trojans to be installed on the user's system.

Many of these additionally are mass spammed by the author to entice people into double-clicking on them.

Alternatively they may be installed by visiting a malicious web page (either by clicking on a link, or by the website hosting a scripted exploit which installs the Downloader onto the user's system with no user interaction.

   

Virus Characteristics

Downloaders are designed to pull files from a remote website and execute the files that have been downloaded. As it is trivial for the malware author to modify the Downloader to refer to a different website or web address, McAfee write detection routines for Downloaders which as a general rule do not include these strings in the detection routines. This allows McAfee to write more generic detections for these threats and to proactively protect customers against future minor variants.

Therefore it is not possible to guarantee which website and/or port is being communicated with.

Also, as the website being communicated is normally controlled by the malware author, any files being downloaded can be remotely modified and the behaviour of these new binaries altered - possibly with every user infection.

Upon execution the sample evaluated copies itself to the system.  The file name and the registry value name are randomly generated.

System Changes

File Added

• c:\d3.log (10 bytes)

Registry

The following registry keys are created:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Explorer\Discardable\PostSetup\Component Categories\{00021492-0000-
 0000-C000-000000000046}
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Explorer\Discardable\PostSetup\Component Categories\{00021492-0000-
 0000-C000-000000000046}\Enum

The following values are added:

• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Games Acceleration" svshost.exe
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Internet Connection Wizard" stisvsq.exe
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Internet Mail and News" msqdevl.exe
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Microsoft Internet Acceleration Utility" iau.exe
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Microsoft Management Console" lssas.exe
• HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
 Run "Multimedia extensions" mservice.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Games Acceleration" svshost.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Internet Connection Wizard" stisvsq.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Internet Mail and News" msqdevl.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Microsoft Internet Acceleration Utility" iau.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Microsoft Management Console" lssas.exe
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\
 CurrentVersion\Run "Multimedia extensions" mservice.exe

   

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.

   

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