why "00 DB 00" in the binaries

[thomas_remkus]

Trying to understand more of my current work in progress and I ran in through OllyDbg. The ASM is very interesting but what's more interesting is that this very small file (2k) has hundreds of lines of "00 DB 00" after what I thought was the end of the file. Why are these important?

[Vortex]

Those padding bytes are used to align the size of files. Sections of portable executables are aligned to the standard value 512.

[thomas_remkus]

The binary I have in question is really very small where it's related to code. Is there a switch that I can use that will make this pad as limited as possible?

[hutch--]

Thomas,

Its the format of a portable executable file that sets its minimum size. old DOS COM files were pure memory images so they could be very small but a 32 bit PE file has a dos header, a PE header and any section headers required. The minimum is 2 * 512 byte sections and the rest is PE specification data and any padding required to make the section the right size.

[thomas_remkus]

Perfect. That taught me the answer. Thank you.

[jdoe]

You can use the /ALIGN swith of link.exe to get smaller win32 PE (<1024 bytes) but it may not run on every win32 platform.

[thomas_remkus]

Oh. Then I'll avoid this. Thanks for the information, and the warning.