Can .dat files be malicious?

  ened 18:56 12 Jan 2006


My Father has discovered that one day in December 25gig worth of .dat files arrived on his machine. That is not a misprint.

He seems to be unable to delete them and unfortunately I am not there.

He feels he can leave them as his machine is running normally but I certainly would not be happy if I had downloaded them. He says he was not downloading anything that he can remember but they have appeared on his C drive.

He has sent me the first (of 800 odd):

Spybot,adaware and even Trendmicro live have all given him a clean bill of health.

My question is: Can these be harmful?

I have to go now. will be back in the morning.


  mattyc_92 19:00 12 Jan 2006

A *.dat file could be litery ANYTHING.... From music to pictures, from documents to programs....

There is no way to actually be sure what they are......
Where are these *.dat files located on his drive? and what operating System is he using?

  GANDALF <|:-)> 19:14 12 Jan 2006

click here use it and see if it pulls them out. As they are temp. files it should do.


  Thalmus 19:27 12 Jan 2006

If you got some called index.dat then they are files that keep a recorde of your internet browsing and are not deleted when you clear your internet history

Download and install index.dat suite (click here) which will let you view and delete your index.dat files

  ened 06:23 13 Jan 2006

Thankyou GANDALF <|:-)> and Thalmus.

I will forward those links to him and let you know the result.

It was a month or so ago but it is still a mystery to me how they could have been downloaded without his becoming suspicious.

  octal 06:56 13 Jan 2006

You can open dat files if you have a Hex editor, most of the information will look garbled, but there sometimes is lines of text that refer to the application or system that uses them.

I have tried in my system and can read all the dat files in the Windows partition.

  ened 10:23 13 Jan 2006

Obviously I am not getting the full story and I am hundreds of miles away.

But these files are apparently sitting in the C drive (ex-directory as it were).

I have sent him the info from earlier and am waiting to hear from him.

  rawprawn 10:33 13 Jan 2006

Try changing .dat to .txt and open in Notepad, this sometimes works enough for you to see.

  ened 17:19 16 Jan 2006

Sorry not to have got back before but I have no news really except that he removed three of these files manually and then found he was unable to access any web pages.

It is a bit frustrating really but thanks for your help.

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