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Worm:Win32/Vobfus.AC

First posted on 24 September 2010.
Source: SecurityHome

Aliases :

Worm:Win32/Vobfus.AC is also known as Mal_VBNA (Trend Micro), Trojan.Win32.VBKrypt.fsk (Kaspersky), W32.Changeup (Symantec).

Explanation :

Worm:Win32/Vobfus.AC 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.
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Worm:Win32/Vobfus.AC 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. Installation Worm:Win32/Vobfus.AC creates the following files on an affected computer:

c:\documents and settings\administrator\zofoy.exe

Spreads via€¦ Removable drives Worm:Win32/Vobfus.AC may create the following files on targeted drives when spreading:

<targeted drive>:\new folder.lnk

<targeted drive>:\subst.lnk

<targeted drive>:\zofoy.exe

<targeted drive>:\zofoyx.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. Payload Contacts remote host Worm:Win32/Vobfus.AC may contact a remote host at ns1.codeconline.biz using port 8000. 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 dd2ef827ca9d14027cd0127d7980e52ab28228e9.

Last update 24 September 2010

 

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