Re: problem in bypassing stack randomization ("call *%edx" technique)

[purelysp4m () hotmail com]

The technique is explained in greater detail at http://milw0rm.org/papers/55 , but unfortunately it only talks about 
JMP *%esp

By playing around a bit, it looks like %edx always points to the command-line argument after the one you pass to 
strcpy(). That is, if you do strcpy(vuln,argv[73]), %edx will point to argv[74].
If you use strncpy, no registers will point to any of your command-line arguments.

It is, to my knowledge, not possible to directly edit %edx. I'd suggest using gdb to find the contents of the registers 
when the program crashes, and then figure out how to control the data at one of those locations :)