Question

My dearest stackoverflowers,

I want to access the serialized data contained in files with strange, to me, extensions. The bulk of the data seems to be in a .st and an .idt file.

The program is meant to be run on Windows, and the unix file command gives me only false positives. Any ideas on either what these extensions mean or on how to investigate and extract their contents?

Below I provide the entirety of the extensions in a long list in hope somebody recognizes them. Googling also gives me false positives. For example: .st is commonly used for ATARI emulation files.

Thanks in advance!

• .cix
• .cmp
• .cnt
• .dam
• .das
• .drf
• .idt
• .irc
• .lxp
• .mp
• .mbr
• .str
• .vlf
• .rpf
• .st
• .st

Answer 1

Some general advice on how to approach this:

1. One way to approach this is to use a site like http://filext.com/ to try to figure out where the files came from. This can be tough, because it’s not like there’s a file extension standard anywhere – anyone can use any extension, so you’re going to have a lot of conflicts/disambiguation issues to solve.
2. Sometimes you can get lucky, and if you open up the files in a plain text editor you can occasionally see plain string data that is readable, which can help identify the general sort of data contained in a file, and therefore help cut down on the possible number of sources for a file. For example, I have often helped people who received a file as an email attachment with no extension, figure out what file type it was using this technique, adding the file extension, and then opening it in the appropriate program.
3. There are also sites like http://www.oldversion.com/ that keep old versions of programs that you (typcially) can download for free. This is especially helpful if the data you’re working with was created 5+ years ago, in a proprietary program, and that program is no longer available/purchasable from the vendor who created it.
4. Once you have a good idea of what files belong to what programs, then you’re probably going to spend a lot of time trying to find online resources for what the structure of the files are. If that isn’t available, you can get a copy of the original program, but either the program won’t open the files you’re interested in or you still want raw access to the data, then try generating some sample output files with data that you input, and go Rosetta Stone on it, comparing your known file to the original file.
5. From there, the additional knowledge you’ll probably want, is to try to find out what language/compiler the software was written in, which can give you a lead on what code libraries were used to serialize the data in the first place. Once you know all that, then it’s matter of reading through any available documentation on the serialization process, and then writing a deserializer.

The one thing this technique won’t solve is, if you’re dealing with corrupt/truncated data files, it may be very difficult to tell the difference between that and whether or not you have the file structure correct. The “Rosetta Stone” technique might be helpful in that case.

Depending on how many different pieces of source software you’re talking about, sounds like a pretty big project. Good luck!