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Hex Editing a File

    Question

  • Hello Friends,

    I have a big doubt regarding hex editing....

    I was hex editing a file and found that

    When i delete  any hex content of an exe file the whole file(exe)  becomes invalid..whereas when i do the same for mp3 file the file still runs

    can anybody explain me why such difference???

    Thanks

    Thursday, September 22, 2011 12:45 PM

Answers

  • The EXE and DLL files in Windows are digitally signed which allows one to easily distinguish the original binary shipped by Microsoft from one that has been tampered with or modified. As soon as any bit of the binary is modified, the digital signature no longer matches and becomes invalid.

    By contrast, MP3 files aren't digitally signed so they can be edited without altering the integrity of the file. 

    For more information:

    http://en.wikipedia.org/wiki/Digital_signature

    Cheers,
    Ben 

    Friday, September 23, 2011 1:49 AM

All replies

  • Hello Friends,

    I have a big doubt regarding hex editing....

    I was hex editing a file and found that

    When i delete  any hex content of an exe file the whole file(exe)  becomes invalid..whereas when i do the same for mp3 file the file still runs

    can anybody explain me why such difference???

    Thanks


    EXE file is supposed secure so noone can edit them. If your editing a system file that will violate the EULA. 

    Microsoft MVP - Windows Expert (IT Pro)
    • Edited by CaptainMVP Thursday, September 22, 2011 1:04 PM
    Thursday, September 22, 2011 1:03 PM
  • Hello Friends,

    I have a big doubt regarding hex editing....

    I was hex editing a file and found that

    When i delete  any hex content of an exe file the whole file(exe)  becomes invalid..whereas when i do the same for mp3 file the file still runs

    can anybody explain me why such difference???

    Thanks


    EXE file is supposed secure so noone can edit them. If your editing a system file that will violate the EULA. 

    Microsoft MVP - Windows Expert (IT Pro)
    So i think only modifying or replacing is the option...right
    Thursday, September 22, 2011 1:12 PM


  • EXE file is supposed secure so noone can edit them. If your editing a system file that will violate the EULA. 

    Microsoft MVP - Windows Expert (IT Pro)
    But in case of virus attack the virus attaches itself to the code of exe file...doesnt that violate the EULA..???
    Thursday, September 22, 2011 1:43 PM
  • Why you choose the Windows 8 developer preview forum and ask a virus question? Are you writing a virus for Windows 8? 



    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP
    Thursday, September 22, 2011 2:27 PM
  • Why you choose the Windows 8 developer preview forum and ask a virus question? Are you writing a virus for Windows 8? 



    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP

    Why do you think I am creating a virus........ there are many forums that give direct detail knowledge for creating virus...I just want to know how does virus attach to a program????
    Thursday, September 22, 2011 5:08 PM
  • This forum is for Windows 8 developer preview, when you post something here the assumptions is that you are a software developer and your question has something to do with the topic of the forum, thus the question. If you know forums that are closer to your question a better choice is to post to those forums, as off-topic questions get ignored even if the read knows the answer, and get less exposure to the experts in the area you need help with. 



    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP

    Thursday, September 22, 2011 5:47 PM
  • Why you choose the Windows 8 developer preview forum and ask a virus question? Are you writing a virus for Windows 8? 



    The following is signature, not part of post
    Please mark the post answered your question as the answer, and mark other helpful posts as helpful, so they will appear differently to other users who are visiting your thread for the same problem.
    Visual C++ MVP

    Why do you think I am creating a virus........ there are many forums that give direct detail knowledge for creating virus...I just want to know how does virus attach to a program????


    I think with Developer Preview, they meant for "decent developers" or people that would make something useful.
    I'm sorry but I refuse to help you with creating a virus, this is childsplay.
    If you're trying to learn programming, pick up a book or follow lessons, don't make virus's.

    Regards,

    Dylan Meeus


    0x2B |~ 0x2B Blog : www.it-ca.net/blogdylan
    Friday, September 23, 2011 12:55 AM
  • The EXE and DLL files in Windows are digitally signed which allows one to easily distinguish the original binary shipped by Microsoft from one that has been tampered with or modified. As soon as any bit of the binary is modified, the digital signature no longer matches and becomes invalid.

    By contrast, MP3 files aren't digitally signed so they can be edited without altering the integrity of the file. 

    For more information:

    http://en.wikipedia.org/wiki/Digital_signature

    Cheers,
    Ben 

    Friday, September 23, 2011 1:49 AM