Downloader-AZG

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

Overview

-- Update: October 3, 2007 ---

A recent variant was found to be downloaded by malicous scripts hosted on web sites.This variant will be detected as Downloader-AZG with DAT 5134 or later.

Downloaders are designed to pull files from a remote website and execute the files that have been downloaded.


Minimum DAT

4896 (2006-11-15)

Updated DAT

6561 (2011-12-15)

Minimum Engine

5400.1158

File Length

Varies

Description Added

2006-11-15

Description Modified

2007-10-04

Malware Proliferation

Characteristics

-- Update: October 3, 2007 --
The risk assessment of this threat has been updated to Low-Profiled due to media attention at:
http://www.cio.com/article/143254/Malicious_Code_Infects_Chinese_Security_Site

-- Update: October 3, 2007 ---
A recent variant was found to be downloaded by malicous scripts hosted on web sites. This variant will be detected as Downloader-AZG with DAT 5134 or later.

--

Upon execution, the trojan drops the following files.

  • %SystemDrive%:\servets.exe (Downloader-AZG)
  • %SystemDrive%:\AutoRun.inf
  • %SystemDir%\servets.exe (Downloader-AZG)

The following registry keys are added:

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WindowsDowns
    "Description" = (Chinese string)
    "DisplayName" = "Telephots google"
    "ErrorControl" = 0
    "ImagePath" = "%SystemDir%\servets.exe"
    "ObjectName" = "LocalSystem"
    "Start" = 2
    "Type" = 0x110
  • HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\WindowsDowns
    "Description" = (Chinese string)
    "DisplayName" = "Telephots google"
    "ErrorControl" = 0
    "ImagePath" = "%SystemDir%\servets.exe"
    "ObjectName" = "LocalSystem"
    "Start" = 2
    "Type" = 0x110

The trojan attemps to download files from the remote site.

  • http://ads.[removed].com

The following virus/trojan are downloaded.

  • PWS-Mmorpg.gen trojan
  • PWS-LegMir trojan
  • PWS-Zhengtu trojan
  • PWS-OnlineGames.c.dll trojan
  • PWS-QQGame trojan
  • W32/HLLP.Philis.kl virus
  • W32/Fujacks virus

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There are several versions existed. This is a general description. Newer versions require the latest DATs for detection and cleaning.

Upon execution, the trojan drops itself to the following file.

  • %SystemDir%\notaped.exe

Then it adds the following registry key.

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\KSD2Service
    ImagePath = %SystemDir%\notaped.exe

It injects a code into the process "svchost.exe" and downloads a text file that contains a list of URLs from the remote site.

  • http://[removed]ilman.cn/m2.txt

The trojan attempts to download the files listed in the text file.

 

Symptoms

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.

Method 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.

Removal

All Users:
Use specified engine and DAT files for detection and removal.

Additional Windows ME/XP removal considerations

Variants