Alphanumeric shellcode: Difference between revisions

Revision as of 15:14, 3 September 2008

Revision as of 17:27, 1 February 2009

Line 7:

In [[BSCS]] the alphanumeric character have meaning: "a"-"z", "A"-"Z", "0"-"9". No special characters are included.

More specifically, in computer underground terminology, alphanumeric code is [[machine code]] that is written so that it assembles into entirely alphanumeric [[ASCII]] characters such as 0-9, A-Z and a-z<ref>[http://skypher.com/wiki/index.php?title=X86_alphanumeric_opcodes List of x86 Alphanumeric opcodes]</ref><ref>[http://skypher.com/wiki/index.php?title=X64_alphanumeric_opcodes List of x64 alphanumeric opcodes]</ref>. This type of encoding was created by [[Hacker (computer security)|hackers]] to be able to pass machine code through a filter that removes any non-alphanumeric character and still be able to have it perform its intended tasks successfully. (Because normal machine code frequently uses non-alphanumeric characters, these would get removed by such a filter and the code would not be able to pass the filter without being modified to the point where it no longer works). A slightly less restrictive form of this type of encoding is printable code, which uses all [[Control character|printable]] characters such as 0-9, A-Z, a-z, !@#%^&*() etc...

Writing alphanumeric or printable code requires a good understanding of the [[instruction set architecture]] of the machine on which the code is to be executed.

Line 20:

* [http://skypher.com/wiki/index.php?title=Www.edup.tudelft.nl/~bjwever/documentation_alpha2.html.php ALPHA2], an alphanumeric shellcode encoder: Utility to encode normal machine code into alphanumeric (upper-case or mixed-case) ASCII or Unicode text

* [http://www.vividmachines.com/shellcode/shellcode.html#ps Shellcoding for Linux and Windows &mdash; Printable Shellcode]: Explanation and tutorial

== References ==

{{reflist}}

[[Category:Security exploits]]