Re: AMD Sledgehammer and ascii-only shellcode

[Sebastian <scut () NB IN-BERLIN DE>]

Hi.

On Wed, Aug 16, 2000 at 04:33:40AM +0200, Holger van Koll wrote:

> > AFAIK it´s still considered impossible to code shellcode using only
> > ascii-data as commands like jmp, call are not within this range.

Well, it is possible to write ASCII only shellcode (I have seen an
experimental 'a-Z' shellcode decoder), the problem is not the shellcode,
but the data which cannot replaced in most cases: the return address.
On most architectures/operating systems the return address has bytes
that aren't within the 'a-Z' range, and hence couldn't be modified with
a simple overwrite smash if the data is ASCII-filtered.

ciao,
scut

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