How to decompile a certain file type

[AinsleyHarriot539]

I was wanting to know how I can decompile a file that has no extension and the file type shown in file explorer reads "file". If anyone knows how you would be a great help.

[AlwaysFSX]

Do you know what file type it's supposed to be? If you do you can just assign it a file type.

[AinsleyHarriot539]

Just now, AlwaysFSX said:

Do you know what file type it's supposed to be? If you do you can just assign it a file type.

I believe it is a folder but i don't know how to turn it into a folder.

[zMeul]

10 minutes ago, AinsleyHarriot539 said:

I believe it is a folder but i don't know how to turn it into a folder.

what?!

a file can't be a folder nor a folder can be a file

 

maybe you meant an archive

[AlwaysFSX]

6 minutes ago, AinsleyHarriot539 said:

I believe it is a folder but i don't know how to turn it into a folder.

A folder isn't a file type.

[vorticalbox]

post it i will have a go

[mariushm]

It's either a file or a folder.

 

My advice would be to download and use Total Commander , it's like Windows Explorer but much, much better (it's like two windows explorers in parallel and it's super easy to use without mouse, if you bother to learn shortcuts and everything in time).

 

Go in the folder where your file is and press F3 (or click on the button in the bar at the bottom) that says View.  If it's a file, a file viewer should open up and you should be able to see the contents of the file.

If the viewer opens, you should be able to see the first few characters. If it's just a bunch of weird characters, you can switch to viewing the file in Hex mode  (type 3 or go in Options menu then select  Hex mode) and see if it makes it easier.

Most file types have some kind of unique signature at the beginning, for example a JPG picture usually has the string of characters "JFIF" at the beginning, PNG pictures have "PNG", PDF files start with "%PDF" , MKV files have "matroska" near the beginning and so on ... you can see a lot of such signatures here: https://en.wikipedia.org/wiki/List_of_file_signatures

So if you figure out what the file was supposed to be, you can simply right click on the file and hit rename, add the dot and then enter the file extension.

 

 

 

 

[Nuluvius]

1 hour ago, mariushm said:

My advice would be to download and use Total Commander

More like Total Crap... Just don't.

[PirateFish]

Try to use 7zip to see if it's a ZIP or RAR.

[Nuluvius]

9 minutes ago, PirateFish said:

Try to use 7zip to see if it's a ZIP or RAR.

You don't need to, all you need to do is to inspect the hex for a signature.

[Mira Yurizaki]

https://en.wikipedia.org/wiki/File_format#Magic_number

 

If you have a hex editor to open the file with, you can see if it's in one of the common file formats.

 

Or you can throw darts at the board and hope for the best

[Unimportant]

Use the linux "file" command on the file to determine it's type.

If you're on windows, find some windows port of the linux GNU utils.

[AinsleyHarriot539]

To the people who are still interested I have gotten the hex code of the file I would appreciate any help that anyone can give as I am struggling to determine the file type still. As a reference I am using the following wikipedia link.

https://en.wikipedia.org/wiki/List_of_file_signatures

[PirateFish]

22 hours ago, Nuluvius said:

You don't need to, all you need to do is to inspect the hex for a signature.

If it turns out to be a compressed file, then yes you have to unzip it. Also it's a lot easier to try to unzip it then looking for the zip/tar.gz/rar signatures.

 

You don't need to look at the hex for signatures, you could put the file on a HDD, and use a magnetised needle to feel the individual bits, and determine the file that way.

[Nuluvius]

1 hour ago, PirateFish said:

If it turns out to be a compressed file, then yes you have to unzip it.

No... you don't...

1 hour ago, PirateFish said:

Also it's a lot easier to try to unzip it then looking for the zip/tar.gz/rar signatures. Also it's a lot easier to try to unzip it then looking for the zip/tar.gz/rar signatures.

So you think that randomly trying to guess the compression algorithm/methodology, if it is even compressed for that matter - which you won't know upfront, is going to be easier than simply pattern matching the exact one? You will be there for an awfully long time if it turns out to be corrupted, encrypted or indeed not even compressed!

1 hour ago, PirateFish said:

You don't need to look at the hex for signatures, you could put the file on a HDD, and use a magnetised needle to feel the individual bits, and determine the file that way.

Do you even know what you are talking about... What do you think you are looking at in hex?

[PirateFish]

10 minutes ago, Nuluvius said:

No... you don't...

So you think that randomly trying to guess the compression algorithm/methodology, if it is even compressed for that matter - which you won't know upfront, is going to be easier than simply pattern matching the exact one? You will be there for an awfully long time if it turns out to be corrupted, encrypted or indeed not even compressed!

Do you even know what you are talking about... What do you think you are looking at in hex?

There's a hex dump now - get going with your magnetic needle.

[Nuluvius]

4 hours ago, PirateFish said:

There's a hex dump now - get going with your magnetic needle.

And now you have ceased making any sense whatsoever...

[Steven Horton]

On 12/12/2016 at 6:44 AM, Nuluvius said:

You don't need to, all you need to do is to inspect the hex for a signature.

 

I came here to post this, however, the only magic number I could find that matches doesn't seem to indicate anything useful.

I give up -- upload the file and let a linux user 'file' it.

[mariushm]

@AinsleyHarriot539

The file has no recognizable pattern.

 

If you think it may be a movie, you could try dragging it over a video player like VLC (Video Lan Client) or MPC-HC (Media Player Classic Home Cinema), these usually ignore the file extension and are smart enough to try different ways of decoding the file.

[AinsleyHarriot539]

@mariushm I was able to work out that this file contains models for a game. If that is able to help someone who has experience with this. Good luck to you because I am tempted to give up and delete this file.

[straight_stewie]

On 12/14/2016 at 6:01 AM, AinsleyHarriot539 said:

 

@mariushm I was able to work out that this file contains models for a game. If that is able to help someone who has experience with this. Good luck to you because I am tempted to give up and delete this file.

Do you know why the file exists or what program it is attached to?

[AinsleyHarriot539]

13 minutes ago, straight_stewie said:

Do you know why the file exists or what program it is attached to?

The only information I was able to get from the person who this file to me said it was from a Unity game.

[straight_stewie]

5 minutes ago, AinsleyHarriot539 said:

The only information I was able to get from the person who this file to me said it was from a Unity game.

So that makes me question about it's value anyway. If someone sent you a file that you have no use for, and you don't even know what it is, I would delete it for safety and then do a full malware check/file cleaning.

[AinsleyHarriot539]

2 minutes ago, straight_stewie said:

So that makes me question about it's value anyway. If someone sent you a file that you have no use for, and you don't even know what it is, I would delete it for safety and then do a full malware check/file cleaning.

I know the person and he has no clue on how to form malware he said it was from the game Rust and said the file contains models used in game.