Alphanumeric shellcode: Difference between revisions
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In general, in [[computing]], an '''alphanumeric code''' is a series of letters and numbers (hence the name) which are written in a form that can be processed by a computer. |
In general, in [[computing]], an '''alphanumeric code''' is a series of letters and numbers (hence the name) which are written in a form that can be processed by a computer. |
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In [[BSCS]] the alphanumeric character have meaning: "a"-"z", "A"-"Z", "0"-"9". No special characters are included. |
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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>{{cite web |last=SkyLined |url=http://skypher.com/wiki/index.php?title=X86_alphanumeric_opcodes |title=List of x86 Alphanumeric opcodes |publisher=Skypher.com}}</ref><ref>{{cite web |last=SkyLined |url=http://skypher.com/wiki/index.php?title=X64_alphanumeric_opcodes |title=List of x64 alphanumeric opcodes |publisher=Skypher.com}}</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... |
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>{{cite web |last=SkyLined |url=http://skypher.com/wiki/index.php?title=X86_alphanumeric_opcodes |title=List of x86 Alphanumeric opcodes |publisher=Skypher.com}}</ref><ref>{{cite web |last=SkyLined |url=http://skypher.com/wiki/index.php?title=X64_alphanumeric_opcodes |title=List of x64 alphanumeric opcodes |publisher=Skypher.com}}</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... |
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Revision as of 12:06, 4 October 2009
 | This article possibly contains original research. (February 2008) |
- You may be looking for Character encoding.
- or SYNOP and CLIMAT (alphanumeric codes used for meteorological and climatological data transmission)
In general, in computing, an alphanumeric code is a series of letters and numbers (hence the name) which are written in a form that can be processed by a computer.
In BSCS the alphanumeric character have meaning: "a"-"z", "A"-"Z", "0"-"9". No special characters are included.
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[1][2]. This type of encoding was created by 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 printable characters such as 0-9, A-Z, a-z, !@#%^&*() etc...
Writing alphanumeric or printable codes require good understanding instruction set architecture of the machine on which the code is to be executed.
See also
- EICAR test file - a test pattern used to test the installation of the anti virus software, which is written in printable code.
External links
- Writing ia32 alphanumeric shellcodes, an article on how to write alphanumeric shellcode.
- Building IA32 'Unicode-Proof' shellcodes, an article on how to write Unicode proof shellcode.
- Writing IA32 restricted instruction set shellcodes, an article on how to write code that is very limited in the number of characters it can use (such as alphanumeric code).
- ALPHA2, an alphanumeric shellcode encoder: Utility to encode normal machine code into alphanumeric (upper-case or mixed-case) ASCII or Unicode text
- Shellcoding for Linux and Windows — Printable Shellcode: Explanation and tutorial
References
- ^ SkyLined. "List of x86 Alphanumeric opcodes". Skypher.com.
- ^ SkyLined. "List of x64 alphanumeric opcodes". Skypher.com.