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You have been re-routed to the Worm:Win32/Autorun.LD write up because Worm%3aWin32%2fAutorun.LD has been renamed to Worm:Win32/Autorun.LD
 

Worm:Win32/Autorun.LD


Worm:Win32/Autorun.LD is a worm - a self-propagating program that can spread itself from one computer to another. Worms may spread themselves via a variety of different channels in order to compromise new computers. Variants of Worm:Win32/Autorun usually spread using methods that include, but may not be limited to, copying themselves to removable or network drives, and placing an autorun.inf file in the root directory of each affected drive in an attempt to ensure that the worm is run when the removable drive is attached, or the network drive is visited from a remote system supporting the Autorun feature.


What to do now

To detect and remove this threat and other malicious software that may have been installed in your computer, run a full-system scan with an up-to-date antivirus product such as the following: For more information about using antivirus software, see http://www.microsoft.com/windows/antivirus-partners/.

Additional remediation instructions

This threat may make lasting changes to an affected system's configuration that will NOT be restored by detecting and removing this threat. For more information on returning an affected system to its pre-infected state, please see the following information:
Disable Autorun functionality
Worm:Win32/Autorun.LD attempts to spread via removable drives on computers that support Autorun functionality. This is a particularly common method of spreading for many current malware families. For information on disabling Autorun functionality, please see the following article: http://support.microsoft.com/kb/967715/

Threat behavior

Worm:Win32/Autorun.LD is a worm - a self-propagating program that can spread itself from one computer to another. Worms may spread themselves via a variety of different channels in order to compromise new computers. Variants of Worm:Win32/Autorun usually spread using methods that include, but may not be limited to, copying themselves to removable or network drives, and placing an autorun.inf file in the root directory of each affected drive in an attempt to ensure that the worm is run when the removable drive is attached, or the network drive is visited from a remote system supporting the Autorun feature.
Installation
When executed, Worm:Win32/Autorun.LD copies itself to <system folder>\rundll.exe.

Note: <system folder> refers to a variable location that is determined by the malware by querying the Operating System. The default installation location for the System folder for Windows 2000 and NT is C:\Winnt\System32; and for XP, Vista, and 7 is C:\Windows\System32.

The malware modifies the following registry entries to ensure that its copy executes at each Windows start:

Adds value: "rundll"
With data: "c:\windows\system32\rundll.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

The malware creates the following files on an affected computer:

  • c:\autorun.inf
  • c:\rundll.exe
Spreads via…
Removable and network drives
Worm:Win32/Autorun.LD may create the following files on targeted drives when spreading:

  • <targeted drive>:\rundll.exe

It also places an autorun.inf file in the root directory of the targeted drive. Such autorun.inf files contain execution instructions for the operating system, so that when the removable drive is accessed from another computer supporting the Autorun feature, the malware is launched automatically.

Note: This worm was observed to write an executable and create an autorun.inf file on a targeted drive in our automated testing environment. This is particularly common malware behavior, generally utilized in order to spread malware from computer to computer.
It should also be noted that autorun.inf files on their own are not necessarily a sign of infection, as they are used by legitimate programs and installation CDs.

This malware description was produced and published using our automated analysis system's examination of file SHA1 30cbbed2949404dee63fde301fe65d15b29b6d23.

Symptoms

System changes
The following system changes may indicate the presence of this malware:

  • The presence of the following files:

  • <system folder>\rundll.exe
    c:\autorun.inf
    c:\rundll.exe

  • The presence of the following registry modifications:
  • Adds value: "rundll"
    With data: "c:\windows\system32\rundll.exe"
    To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run


Prevention


Alert level: Severe
First detected by definition: 1.55.492.0
Latest detected by definition: 1.187.2293.0 and higher
First detected on: Mar 25, 2009
This entry was first published on: Mar 29, 2012
This entry was updated on: Mar 30, 2012

This threat is also detected as:
  • W32/USBAgent (McAfee)
  • Possible_Otorun8 (Trend Micro)
  • Worm.Win32.VB.fi (Kaspersky)
  • W32.SillyFDC (Symantec)