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Worm:Win32/Autorun.AHT

First posted on 01 April 2014.
Source: Microsoft

Aliases :

There are no other names known for Worm:Win32/Autorun.AHT.

Explanation :

Threat behavior

Installation

Worm:Win32/Autorun.AHT creates the following files on your PC:

• \inrv.exe

Spreads via€¦

Removable and network drives

Worm:Win32/Autorun.AHT can copy itself to network and removable drives, such as USB flash drives. It also creates an autorun.inf file in the root folder of the removable drive. The file has instructions to launch the malware automatically when the removable drive is connected to a PC with the Autorun feature turned on. This is a common way for malware to spread. However, autorun.inf files on their own are not necessarily a sign of infection; they are also used by legitimate programs.

We haven't seen this worm create an autorun.inf file. This could be because it doesn't spread immediately, or it might be ordered to spread from a remote source.

Payload

Changes browser settings

Worm:Win32/Autorun.AHT changes the start page for Internet Explorer to http://www.microsoft.com/isapi/redir.dll?prd={sub_prd}&clcid={sub_clsid}&pver={sub_pver}&ar=home by making the following registry modification:

Sets value: "Start Page"
With data: "http://www.microsoft.com/isapi/redir.dll?prd={sub_prd}&clcid={sub_clsid}&pver={sub_pver}&ar=home"
In subkey: HKCU\Software\Microsoft\Internet Explorer\Main
This malware description was produced and published using automated analysis of file SHA1 895c08f65ec7fab5f5c44fc48d62a41b9fb3801c.Symptoms

System changes

The following could indicate that you have this threat on your PC:

• You have these files:
  
  \inrv.exe

• You see these entries or keys in your registry:

Sets value: "Start Page"
With data: "http://www.microsoft.com/isapi/redir.dll?prd={sub_prd}&clcid={sub_clsid}&pver={sub_pver}&ar=home"
In subkey: HKCU\Software\Microsoft\Internet Explorer\Main

Last update 01 April 2014

 

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