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.
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:
Removable and network drives
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.