ZeroAccess.as

This page shows details and results of our analysis on the malware ZeroAccess.as

Overview

Rootkits are programs that can potentially be used by any malware to hide, or stealth, files, processes, registry keys, and network connections. ZeroAccess.a is one of such detections for this class of malicious programs. Unlike viruses, ZeroAccess does not self-replicate. It is spread manually, often under the premise that it is 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.

Aliases

  • AntiVir - TR/ATRAPS.Gen2
  • Microsoft - Trojan:Win64/Sirefef.E
  • NOD32 - a variant of Win32/Agent.TEO


Minimum Engine

5600.1067

File Length

varies

Description Added

2012-01-04

Description Modified

2012-03-21

Malware Proliferation

Characteristics

ZeroAccess.as Trojan is a component of the ZeroAccess.a rootkit.

ZeroAccess.a is a multi-component malware that moderates an infected user's Internet experience by modifying search results.

ZeroAccess.as Trojan is the component responsible for clicking links supplied by a remote attacker.  The links are determined by a file located in a remote server accessed by this Trojan.

This Trojan generates traffic for certain websites without the user's knowledge.

ZeroAccess.as may be present as the file "click_shell.dll" in the %WinDir% folder. However, if a user attempts to access these folders, the rootkit may terminate the accessing process.

Also it creates an event with the following name:

\BaseNamedObjects\{8A73A2A1-7628-4123-88AD-FF9F4F2F6FEA}

Symptoms

These symptoms of this detection are the files, registry, and network communication referenced in the characteristics section.

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, e-mail, 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.

Variants