digitalmars.D - Obfuscating function names and the like inside exe file

bobef (3/3) Mar 20 2010 Hello all,

Bane (2/7) Mar 20 2010 Compress/encode sensitive data and give meaningless names to function/cl...

Steve Teale (5/7) Mar 20 2010 Bane,

Robert Jacques (8/15) Mar 20 2010 Regarding function names/etc. I'd expect any industry standard obfuscato...

Ellery Newcomer (3/20) Mar 20 2010 Doesn't that just put "important name" in the mangled name of ct_encrypt...

BCS (5/30) Mar 20 2010 Use a CTFE compression function and that problem should go away (as long...

Walter Bright (9/14) Mar 20 2010 1. make sure you're not compiling with debug info (-g) on.

Nick Sabalausky (3/20) Mar 20 2010 Wouldn't compiler errors still refer to the obfuscated name?

Walter Bright (2/9) Mar 20 2010 Sometimes.

Mike James (2/12) Mar 21 2010 Ah... An obfuscated answer to an obfuscation question.

Bane (3/13) Mar 20 2010 Lol :))))
Daniel Keep (29/34) Mar 20 2010 module seakrit;
bobef (5/17) Mar 21 2010 Too much manual work. Any clues how I can automate this? At least where ...

Walter Bright (4/11) Mar 21 2010 You can write a simple D program that contains a list of strings to patc...
BCS (10/33) Mar 21 2010 If you know what to look for, some kind of find/replace might work.

bobef <_asd_ASd_ASD_Asdasd_ASd asdasda___dasd.com> writes:

Hello all,

I was wondering if someone know of way to obfuscate all the strings and
function names and class names inside DMD Windows generated exe file. Opening
the file with notepad shows all kinds of strings and names in clear text and
since my application handles some sensitive data it gives me an extra feeling
of insecurity. Any suggestions?

Thanks

Mar 20 2010

Bane <branimir.milosavljevic gmail.com> writes:

bobef Wrote:

 Hello all,
 
 I was wondering if someone know of way to obfuscate all the strings and
function names and class names inside DMD Windows generated exe file. Opening
the file with notepad shows all kinds of strings and names in clear text and
since my application handles some sensitive data it gives me an extra feeling
of insecurity. Any suggestions?
 
 Thanks

Compress/encode sensitive data and give meaningless names to function/classes ?
:)

Mar 20 2010

Steve Teale <steve.teale britseyeview.com> writes:

On Sat, 20 Mar 2010 09:53:17 -0400, Bane wrote:

 Compress/encode sensitive data and give meaningless names to

 function/classes ? :)

Bane,

You have become a changed person - these days you are tolerant to a 
fault. Do try to keep a balance!

Steve

Mar 20 2010

"Robert Jacques" <sandford jhu.edu> writes:

On Sat, 20 Mar 2010 10:12:14 -0300, bobef  
<_asd_ASd_ASD_Asdasd_ASd asdasda___dasd.com> wrote:
 Hello all,

 I was wondering if someone know of way to obfuscate all the strings and  
 function names and class names inside DMD Windows generated exe file.  
 Opening the file with notepad shows all kinds of strings and names in  
 clear text and since my application handles some sensitive data it gives  
 me an extra feeling of insecurity. Any suggestions?

 Thanks

Regarding function names/etc. I'd expect any industry standard obfuscator  
would scramble them for you. A bigger problem is the data segment which  
stores any constant strings, etc. If you really have to include them in  
your program, I'd recommend writing a compile time encrypt and runtime  
decrypt function pair. i.e.

string name = rt_decrypt(ct_encrypt!"important name");

Mar 20 2010

Ellery Newcomer <ellery-newcomer utulsa.edu> writes:

On 03/20/2010 11:24 AM, Robert Jacques wrote:
 On Sat, 20 Mar 2010 10:12:14 -0300, bobef
 <_asd_ASd_ASD_Asdasd_ASd asdasda___dasd.com> wrote:
 Hello all,

 I was wondering if someone know of way to obfuscate all the strings
 and function names and class names inside DMD Windows generated exe
 file. Opening the file with notepad shows all kinds of strings and
 names in clear text and since my application handles some sensitive
 data it gives me an extra feeling of insecurity. Any suggestions?

 Thanks

 Regarding function names/etc. I'd expect any industry standard
 obfuscator would scramble them for you. A bigger problem is the data
 segment which stores any constant strings, etc. If you really have to
 include them in your program, I'd recommend writing a compile time
 encrypt and runtime decrypt function pair. i.e.

 string name = rt_decrypt(ct_encrypt!"important name");

Doesn't that just put "important name" in the mangled name of ct_encrypt 
(albeit in hex)?

Mar 20 2010

BCS <none anon.com> writes:

Hello Ellery,

 On 03/20/2010 11:24 AM, Robert Jacques wrote:
 
 On Sat, 20 Mar 2010 10:12:14 -0300, bobef
 <_asd_ASd_ASD_Asdasd_ASd asdasda___dasd.com> wrote:
 Hello all,
 
 I was wondering if someone know of way to obfuscate all the strings
 and function names and class names inside DMD Windows generated exe
 file. Opening the file with notepad shows all kinds of strings and
 names in clear text and since my application handles some sensitive
 data it gives me an extra feeling of insecurity. Any suggestions?
 
 Thanks
 

 Regarding function names/etc. I'd expect any industry standard
 obfuscator would scramble them for you. A bigger problem is the data
 segment which stores any constant strings, etc. If you really have to
 include them in your program, I'd recommend writing a compile time
 encrypt and runtime decrypt function pair. i.e.
 
 string name = rt_decrypt(ct_encrypt!"important name");
 

 Doesn't that just put "important name" in the mangled name of
 ct_encrypt (albeit in hex)?
 

Use a CTFE compression function and that problem should go away (as long 
as you can force CTFE).

-- 
... <IXOYE><

Mar 20 2010

Walter Bright <newshound1 digitalmars.com> writes:

bobef wrote:
 I was wondering if someone know of way to obfuscate all the strings and
 function names and class names inside DMD Windows generated exe file. Opening
 the file with notepad shows all kinds of strings and names in clear text and
 since my application handles some sensitive data it gives me an extra feeling
 of insecurity. Any suggestions?

1. make sure you're not compiling with debug info (-g) on.

2. you can just use a bit editor to stomp on those names in the executable 
(replace them with XXXXX or whatever). The exe files are not checksummed, so 
this should be straightforward.

3. rename your sensitive classes to obscure names, then alias them to a
readable 
name. The alias name shouldn't appear in the executable:

     class CXX97ASDFXX { }
     alias CXX97ASDFXX mySensitiveName;

Mar 20 2010

"Nick Sabalausky" <a a.a> writes:

"Walter Bright" <newshound1 digitalmars.com> wrote in message 
news:ho34du$2lij$1 digitalmars.com...
 bobef wrote:
 I was wondering if someone know of way to obfuscate all the strings and
 function names and class names inside DMD Windows generated exe file. 
 Opening
 the file with notepad shows all kinds of strings and names in clear text 
 and
 since my application handles some sensitive data it gives me an extra 
 feeling
 of insecurity. Any suggestions?

 1. make sure you're not compiling with debug info (-g) on.

 2. you can just use a bit editor to stomp on those names in the executable 
 (replace them with XXXXX or whatever). The exe files are not checksummed, 
 so this should be straightforward.

 3. rename your sensitive classes to obscure names, then alias them to a 
 readable name. The alias name shouldn't appear in the executable:

     class CXX97ASDFXX { }
     alias CXX97ASDFXX mySensitiveName;

Wouldn't compiler errors still refer to the obfuscated name?

Mar 20 2010

Walter Bright <newshound1 digitalmars.com> writes:

Nick Sabalausky wrote:
 3. rename your sensitive classes to obscure names, then alias them to a 
 readable name. The alias name shouldn't appear in the executable:

     class CXX97ASDFXX { }
     alias CXX97ASDFXX mySensitiveName;

 
 Wouldn't compiler errors still refer to the obfuscated name? 

Sometimes.

Mar 20 2010

Mike James <foo bar.com> writes:

Walter Bright Wrote:

 Nick Sabalausky wrote:
 3. rename your sensitive classes to obscure names, then alias them to a 
 readable name. The alias name shouldn't appear in the executable:

     class CXX97ASDFXX { }
     alias CXX97ASDFXX mySensitiveName;

 
 Wouldn't compiler errors still refer to the obfuscated name? 

 
 Sometimes.

Ah... An obfuscated answer to an obfuscation question.

Mar 21 2010

Bane <branimir.milosavljevic gmail.com> writes:

Walter Bright Wrote:

 Nick Sabalausky wrote:
 3. rename your sensitive classes to obscure names, then alias them to a 
 readable name. The alias name shouldn't appear in the executable:

     class CXX97ASDFXX { }
     alias CXX97ASDFXX mySensitiveName;

 
 Wouldn't compiler errors still refer to the obfuscated name? 

 
 Sometimes.

Lol :))))

There goes determinism down the drain.

Mar 20 2010

Daniel Keep <daniel.keep.lists gmail.com> writes:

bobef wrote:
 Hello all,
 
 I was wondering if someone know of way to obfuscate all the strings and
function names and class names inside DMD Windows generated exe file. Opening
the file with notepad shows all kinds of strings and names in clear text and
since my application handles some sensitive data it gives me an extra feeling
of insecurity. Any suggestions?
 
 Thanks

module seakrit;

char[] supar_enkript(char[] mah_secret)
{
    char[] result = mah_secret.dup;
    for( size_t i=0; i<result.length; ++i )
        result[i] = ~result[i];
    return result;
}

alias supar_enkript supar_dekript;

const supar_seakrit_password = supar_enkript("O HAI THAR");

import tango.io.Stdout;

void main()
{
    Stdout("Tha supar seakrit password is: ")
        (supar_dekript(supar_seakrit_password)).newline;
}


Note that simply using supar_enkript("O HAI THAR") isn't sufficient; you
have to make sure you trigger compile-time evaluation or you'll end up
with the seakrit in the object file.

For extra sekuritee, put supar_enkript in another module that you never
link to.

Of course, the reason for all the bad spelling is to indicate that this
isn't really something I can imagine helping.  If your program handles
sensitive data, protect the data, not your program.

If your program *contains* sensitive information, don't give it to the
wrong people.

If someone is really, seriously determined to get at that information,
there's nothing you can do to stop them.

Mar 20 2010

bobef <_asd_ASd_ASD_Asdasd_ASd asdasda___dasd.com> writes:

Walter Bright Wrote:

 
 1. make sure you're not compiling with debug info (-g) on.
 

Bye bye stack traces... :(

 2. you can just use a bit editor to stomp on those names in the executable 
 (replace them with XXXXX or whatever). The exe files are not checksummed, so 
 this should be straightforward.
 

Too much manual work. Any clues how I can automate this? At least where I
should look for info?

 3. rename your sensitive classes to obscure names, then alias them to a
readable 
 name. The alias name shouldn't appear in the executable:
 
      class CXX97ASDFXX { }
      alias CXX97ASDFXX mySensitiveName;

Nice idea. Didn't thought about it. But it won't work for external libraries.
For example if I'm using dcrypt it will be obvious I'm using one of its
supported ciphers for my encrypted data. I wouldn't wish this to be so obvious,
at least not for people without reverse-engineering skills.

Thanks.

Mar 21 2010

Walter Bright <newshound1 digitalmars.com> writes:

bobef wrote:
 Walter Bright Wrote:

  >> 2. you can just use a bit editor to stomp on those names in the executable
  (replace them with XXXXX or whatever). The exe files are not checksummed,
 so this should be straightforward.
 

 
 Too much manual work. Any clues how I can automate this? At least where I
 should look for info?


You can write a simple D program that contains a list of strings to patch. It 
reads the exe file, patches it, and writes it back out.

Mar 21 2010

BCS <none anon.com> writes:

Hello bobef,

 Walter Bright Wrote:
 
 1. make sure you're not compiling with debug info (-g) on.
 

 Bye bye stack traces... :(
 

Only for release builds.

 2. you can just use a bit editor to stomp on those names in the
 executable (replace them with XXXXX or whatever). The exe files are
 not checksummed, so this should be straightforward.
 

 Too much manual work. Any clues how I can automate this? At least
 where I should look for info?
 

If you know what to look for, some kind of find/replace might work.

 3. rename your sensitive classes to obscure names, then alias them to
 a readable name. The alias name shouldn't appear in the executable:
 
 class CXX97ASDFXX { }
 alias CXX97ASDFXX mySensitiveName;

 Nice idea. Didn't thought about it. But it won't work for external
 libraries. For example if I'm using dcrypt it will be obvious I'm
 using one of its supported ciphers for my encrypted data. I wouldn't
 wish this to be so obvious, at least not for people without
 reverse-engineering skills.

I'd assume anyone who can identify the cypher from function names and apply 
it to strings in the file already has reverse-engineering skills. And if 
you are considering the attacker knowing what cypher you are using to be 
a security issue, don't bother I anyone able to think about cracking any 
real cypher can get that from the binary no matter what you do.

-- 
... <IXOYE><

Mar 21 2010

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digitalmars.D - Obfuscating function names and the like inside exe file