Exetools  

Go Back   Exetools > General > General Discussion

Notices

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old 12-12-2015, 15:24
BlackWhite BlackWhite is offline
Friend
 
Join Date: Apr 2013
Posts: 85
Rept. Given: 4
Rept. Rcvd 14 Times in 6 Posts
Thanks Given: 14
Thanks Rcvd at 56 Times in 25 Posts
BlackWhite Reputation: 14
Post It's not so difficult to produce two md5-collided exe files

It's well known that for a given md5 hash, we have no way to
calculate its message. And for the same reason, for a given file,
we have no way to produce another file whose md5 hash equals
to the given one.
According to Wang Xiaoyun's theory, we can produce two
128-bit data blocks whose md5 hashes collide. So why don't
we exploit these 128-bit collisions to produce two md5-collided
exe files?
Here is my method. Let's assume the first exe file is exe1, and
the other is exe2, then these two files are composed as follows:
exe1 = if(condition) func1(); else func2(); + func1() + func2() + md5_1
exe2 = if(condition) func1(); else func2(); + func1() + func2() + md5_2
Here "if(condition) func1(); else func2(); + func1() + func2()" is the
compiled exe file corresponding to exe1 or exe2(actually their source codes
are the same), while md5_1 & md5_2 are overlays appended to the compiled
exe file. And, md5_1 and md5_2 are two 128-bit md5-collided data blocks
calculated by applying Wang's theory, and on producing these collided
blocks, we should not use MD5's default seed values(0x67452301,
0xEFCDAB89, 0x98BADCFE, 0x10325476), in stead, we should use
md5(compiled exe file) as md5's seed value where the final step called
md5_final() should be removed, so that the collision between
md5_1 and md5_2 can be enlarged and finally results in the collision between
exe1 and exe2.
The "condition" mentioned above is to check one bit of the overlay.
The attachment is a zip file containing the source code and 2 md5-collided exe files.
Attached Files
File Type: zip collide.zip (55.9 KB, 37 views)
Reply With Quote
The Following User Gave Reputation+1 to BlackWhite For This Useful Post:
niculaita (12-12-2015)
The Following 2 Users Say Thank You to BlackWhite For This Useful Post:
quygia128 (12-30-2015), synkro (02-13-2016)
 


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Difficult debugging situation Git General Discussion 4 10-21-2005 20:13
cracking jcreator, is it difficult? doby General Discussion 6 09-27-2004 16:15


All times are GMT +8. The time now is 05:39.


Always Your Best Friend: Aaron, JMI, ahmadmansoor, ZeNiX, chessgod101
( Since 1998 )