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I have a binary file. I don't know how it's formatted, I only know it comes from a delphi code.

Does it exist any way to analyze a binary file?

Does it exist any "pattern" to analyze and deserialize the binary content of a file with unknown format?

MSalters
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Ricibald
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12 Answers12

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Try these:

  1. Deserialize data: analyze how it's compiled your exe (try File Analyzer). Try to deserialize the binary data with the language discovered. Then serialize it in a xml format (language-indipendent) that every programming language can understand
  2. Analyze the binary data: try to save various versions of the file with little variation and use a diff program to analyze the meaning of every bit with an hex editor. Use it in conjunction with binary hacking techniques (like How to crack a Binary File Format by Frans Faase)
  3. Reverse Engineer the application: try getting code using reverse engineering tools for the programming language used for build the app (found with File Analyzer). Otherwise use disassembler analysis tool like IDA Pro Disassembler
Ramesh Maharjan
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Ricibald
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    maybe you should have marked an answer, instead of providing a summary of what was said. – Geo Jun 23 '09 at 09:33
  • I think that all are "partial" answer. So I reconstruct a summary and if there are no answer I will mark this summary as the answer – Ricibald Jun 23 '09 at 09:39
  • Yeah, except none of them were your own. – Geo Jun 23 '09 at 11:01
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    Ok, so this question will never have an answer! If you want, copy and paste this answer. I will be very happy to mark your answer! And you will be very happy too! I'm not interested about reputation, I only want to mark an answer for this question. And you? What is your real interest? – Ricibald Jun 23 '09 at 11:29
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    if you look at other questions, when the author wanted to provide a summary, he edited the question and added that there. I don't care about the reputation, but these answers were provided by the users. – Geo Jun 23 '09 at 13:59
  • ok, I think that was correct to put the answer here. But if not I move it in my question – Ricibald Jun 23 '09 at 14:16
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    @Geo Sometimes who he asked the question is the one that has invested the more effort on the topic. Having said that, he might be a good candidate to provide an answer, since he probably has checked users' recommended solution. I can't find anything bad on that for the community, once more since there are rules in place. – thanos.a Jan 19 '17 at 09:48
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    The link to File Analyzer is broken. Where can it be found today? – leifericf Apr 09 '18 at 08:04
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    http://vnet.times.lv/exe/fa.rar link is not working @Ricibald – Chaminda Bandara May 21 '20 at 19:06
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For my hobby project I had to reverse engineer some old game files. My approaches were:

  • Have a good hex editor.
  • Look for readable words in the binary file. Note how their distribution is. If the distance between them is constant you know it is a listing.
  • Look for 2-3 consequent zeros. Might indicate an int32 value.
  • Some dwords might be pointers into the file.
  • Try to identify reoccurring patterns in the file.
  • Seeing lots of C0-CF might indicate RLE compressed data.
akarnokd
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7

Reverse engineering a binary file when you have some idea of what it represents is a very time consuming process. If you have no idea what it is then it will be even harder.

It is possible though, but you have to have a pretty good reason for doing so.

The first step would be to open it up in a hex editor of your choice and see if you can find any English text to point you in the direction of what the file is even supposed to represent. From there, Google "Reverse Engineering binary files", there are much more knowledgeable people than me that have written guides about it.

colithium
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5

The "strings" program from GNU binutils is very useful. It will print the strings of printable characters in a file, quite often giving a clue to what a file contains or a program does.

Andreas Fugl
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If the data represents serialized Delphi objects, you should start reading about the Delphi serialization process. If that's the case, I think your best bet would be to load it using Delphi and continue your analysis from the IDE. Some informations about Delphi serialization can be found here.

EDIT: if the file does contain serialized delphi objects, then you should write a small delphi program that loads it, and "convert" the data yourself to something neutral, like xml. If you manage to do this, you should check and see if delphi supports serializing to xml. Then, you could access those objects from any language.

Geo
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  • If it's a serialized delphi data, how can I use it in a c# or objective-c program? – Ricibald Jun 22 '09 at 09:53
  • but it needs a delphi interpreter. If I have my single application that open this file I can't. I have to execute two distinct applications. – Ricibald Jun 22 '09 at 10:46
  • Yes. You need to convert the object to something usable from anywhere. You can execute the converter from your main application's code, and work on the resulted files. It's how I would do it. – Geo Jun 22 '09 at 10:55
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The unix "file" command is really useful - I don't know if there is anything like it in windows. You run it like this:

file myfile.ext

And it spits out a text description based on the magic numbers and data contained therein.

Probably it is contained within cygwin.

1800 INFORMATION
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    He will probably get "octet-stream" which will confuse him more. ".bin" files (I guess it is) aren't "standardized" and as colithium said, he probably needs to RE. – LiraNuna Jun 22 '09 at 08:36
  • That's what "file" does - it doesn't look at the extension at all – 1800 INFORMATION Jun 22 '09 at 08:42
  • "file" looks for magic numbers as you said, but only magic numbers of knows filetypes. So it most likely will find .jpg, .tar.gz, .avi etc. etc., but a custom binary file-structure is not a known filetype (if it was, he wouldn't have this problem in the first place :) ) – cwap Jun 22 '09 at 14:15
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If you have access to the application that creates the file, you can apply changes to the application, then save the file and see the effects (Keep in mind that numbers are probably stored in little endian):

  • First create the file repeatedly. If the files are not binary equal, the current date/time is probably stored in the area where hte differences occur.
  • Maybe you want to repeat that with the software running under different environments, to see if OS version etc are stored, but this is rather unusual.
  • Next you can try to change single variables and create several files that only differ in the value of this variable. This helps you identify where this variable is stored.
  • That way you can also exclude variables that are not stored in the file: If you change them, but the files created are identical, they are not stored.

In order to test the hypotheses you worked out with the steps above, edit one of the files and have the application read it.

If you don't have access to the application itself, I suggest that you forget about it and find another way to solve your problem. There is a very high probability that it will be faster...

Treb
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If file does not give a meaningful answer, you may want to try TRiD by Marco Pontello to determine whether your data is stored in a known format.

hillu
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  • I tried it but it says about the file: "Program X Format". Well... I already know that it's a file coming from the program X – Ricibald Jun 22 '09 at 14:40
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Get the Delphi application and open it in IDA Pro freeware version, and find where it writes the file, and decode how it writes the file that way.

Unless it's plan text.

Simeon Pilgrim
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Unlike traditional hex editors which only display the raw hex bytes of a file, 010 Editor can also parse a file into a hierarchical structure using a Binary Template. The results of running a Binary Template are much easier to understand and edit than using just the raw hex bytes.

http://www.sweetscape.com/010editor/

Ray Hulha
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Do you know the program that uses it? If so you can hook that programs write to file function and get an idea of what data its writing, the size of the data and where.

More Info: http://www.codeproject.com/KB/DLL/Win32APIHooking_Trouble.aspx

Lodle
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Try to open it in a hex editor and analyse.

Alan Haggai Alavi
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