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MIHIP



Joined: 14 Feb 2013
Posts: 130
MIHIP
Hello! After compiling the program source code on FASM, which he introduces signature (saves) in the file? That is something he himself leaves from? For example, the text "FASM". Well signatures to determine what the program was compiled?
Post 24 Feb 2014, 16:06
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MIHIP



Joined: 14 Feb 2013
Posts: 130
MIHIP
For example, in ever file, compiled by fasm i see the "G‡оR а  ".
Post 24 Feb 2014, 16:07
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
MIHIP,

Why are you guessing? 47 87 EE 52 is a timestamp (IMAGE_FILE_HEADER.TimeDateStamp), it's absolutely normal for it to be equal in the several PEs, especially if they're examples and were compiled together.

P.S. There is "Edit" button (unless you're talking to yourself).
Post 24 Feb 2014, 16:25
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JohnFound



Joined: 16 Jun 2003
Posts: 3502
Location: Bulgaria
JohnFound
FASM does not put any signatures in the compiled files, other than needed for the target file format.

But, because FASM is multipass assembler, it compiles some instructions in a way other assemblers or HLL compilers can't. But IMO, to identify FASM as a compiler for random binary file is impossible (at least with high reliability).
Post 24 Feb 2014, 16:27
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 7751
Location: Kraków, Poland
Tomasz Grysztar
There is no such signature in general, because fasm tries to put into an output file as few things as possible, and so it will not put there anything that is was not told to (or that is not required data for a given format).

However it is sometimes possible to recognize code created with a given assembled by looking at the "footprint" of what instruction encodings it chooses when it has some alternatives to choose from. For example there are two possible encoding of "xor reg,reg" and different assemblers may choose either one.

Other than that, there is one more detail in case of PE output. The PE header contains field called "version of the linker". In case of fasm, it writes its own version there (because it uses no additional linker). AFAIK there are no other linkers with the version numbers in range of the ones used by fasm (but I may be wrong - I do not know all of the linkers out there), so it probably could be used to detect fasm-created PE file.
Post 24 Feb 2014, 16:30
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