Worm:W32/Autorun.GA

Classification

Category :

Malware

Type :

Worm

Summary

A standalone malicious program which uses computer or removable drives to make complete copies of itself.

Removal

Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.

A False Positive is when a file is incorrectly detected as harmful, usually because its code or behavior resembles known harmful programs. A False Positive will usually be fixed in a subsequent database update without any action needed on your part. If you wish, you may also:

  • Check for the latest database updates

    First check if your F-Secure security program is using the latest updates, then try scanning the file again.

  • Submit a sample

    After checking, if you still believe the file is incorrectly detected, you can submit a sample of it for re-analysis.

    Note: If the file was moved to quarantine, you need to collect the file from quarantine before you can submit it.

  • Exclude a file from further scanning

    If you are certain that the file is safe and want to continue using it, you can exclude it from further scanning by the F-Secure security product.

    Note: You need administrative rights to change the settings.

Technical Details

AutoRun.GA creates a copy of itself as the following:

  • C:\Program Files\Microsoft Common\wuauclt.exe

It will change the title of the process to "notepad window".

It also drops two files into the root of available removable drives:

  • autorun.inf
  • wuauclt.exe

It injects codes to svchost.exe and explorer.exe.

It looks for a service that will run manually and then temporarily replaces the driver with malicious driver. It then runs the service and the returns the original driver.

Launchpoint

  • Key: HKLM\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\explorer.exeValue: DebuggerData: C:\Program Files\Microsoft Common\wuauclt.exe

This entry is created for automatic execution when explorer.exe is launched.

The autorun.inf file is an autorun file of wuauclt.exe and contains the following strings:

  • [autorun]open=system.exeshellexecute=system.exeshell\Explore\command=system.exeshell\Open\command=system.exeshell=Explore

Stealth

The worm uses rootkit stealth techniques to hide its presence on the infected machine, including deleting its own installation file once the installation has been completed.

File System Changes

Creates these files:

  • C:\Program Files\Microsoft Common\wuauclt.exe

Process Changes

Writes in memory of these processes:

  • svchost.exe
  • explorer.exe

Network Connections

Attempts to connect to:

  • http://aaszxt.ru/load4/[...].php?v=1&rs=%u&uid=1
  • http://aaszxt.ru/load4/[...].php?v=1&id=%s&rs=%u&cc=0&uid=1
  • http://aaszxt.ru/load4/[...].php?v=1&rs=%u&n=1&uid=1
  • http://aaszxt.ru/load4/[...].php?v=1&id=%s&rs=%u&n=1&cc=0&uid=1
  • http://aaszxr.ru/loadx/[...].php?v=1&rs=%u&uid=1
  • http://aaszxr.ru/loadx/[...].php?v=1&id=%s&rs=%u&cc=0&uid=1
  • http://aaszxr.ru/loadx/[...].php?v=1&rs=%u&n=1&uid=1
  • http://aaszxr.ru/loadx/[...].php?v=1&id=%s&rs=%u&n=1&cc=0&uid=1

Registry Modifications

Sets these values:

  • HKLM\Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\explorer.exeDebuggerC:\Program Files\Microsoft Common\wuauclt.exe