Worm:Win32/SillyFDC.O

Also detected as: W32/YahLover.worm (McAfee), Mal_OtorunN (Trend Micro), W32.SillyFDC (Symantec),

Severe
Worm:Win32/SillyFDC.O
Alert level: Severe
First published: Feb 28, 2013
Latest published: Mar 03, 2013
This radar visually represents the alert level for this malware detection. The red color spreads throughout the disc to indicate whether a threat is moderate, high or severe.

Worm:Win32/SillyFDC.O 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. Commonly, worms may spread directly by copying themselves to removable or network drives, or by attempting to exploit particular vulnerabilities on targeted computers. Worms also often attempt to spread via platforms that require user interaction in order to run. They may send themselves as an attachment to an email or an instant message, or send a link to a copy of themselves in the body of a message. In these cases the message needs to be convincing enough to encourage the victim to click on the link or attachment and run or download a copy of the worm.

Threat behavior

Installation

When executed, Worm:Win32/SillyFDC.O copies itself to <system folder>\msng.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: "msng"
With data: "c:\windows\system32\msng.exe"
To subkey: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

The malware creates the following files on an affected computer:

<system folder>\rundii32.exe
c:\~0002ftd.tmp

Spreads via…

Removable drives

Worm:Win32/SillyFDC.O copies itself to the following locations on removable drives:

<targeted drive>:\show.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.

The malware may also create the following files on targeted drives when spreading:

<targeted drive>:\hot.exe

Payload

Contacts remote host

Worm:Win32/SillyFDC.O may contact a remote host at www.openclose.ir using port 80. Commonly, malware may contact a remote host for the following purposes:

To report a new infection to its author
To receive configuration or other data
To download and execute arbitrary files (including updates or additional malware)
To receive instruction from a remote attacker
To upload data taken from the affected computer

This malware description was produced and published using our automated analysis system's examination of file SHA1 b303ad5c5ee8f1a25169be41df9f87053fd6e090.

Prevention

Take these steps to help prevent infection on your computer.

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Worm:Win32/SillyFDC.O

Symptoms

System changes

What to do now

Additional remediation instructions

Disable Autorun functionality

Threat behavior

Installation

Spreads via…

Payload

Prevention

Search the malware encyclopedia

Worm:Win32/SillyFDC.O /*<![CDATA[*/var threatName=$("#contentTitleText");threatName.html(threatName.html().replace(":",": "))/*]]>*/

Symptoms

System changes

What to do now

Additional remediation instructions

Disable Autorun functionality

Threat behavior

Installation

Spreads via…

Payload

Prevention

Search the malware encyclopedia

Worm:Win32/SillyFDC.O