Skip to main content

Alphanumeric Shellcode

Writing Alphanumeric Shellcode

Step1: First we will write assembly program to spawn a shell:

Objdump of shellcode.s 


Step2: Now lets test this hex shellcode using a C program:

C program to execute shellcode directly

Shellcode Execution

Step3: Convert instruction opcodes from hex to ascii using table given below:

ASCII Shellcode Table
ASCII ValueHex OpcodeAssembly Equivalent
4\x34xor al, 0x## [byte]
5\x35xor eax, 0x######## [DWORD]
6\x36SS Segment Override
<\x3ccmp al, 0x## [byte]
=\x3dcmp eax, 0x######## [DWORD]
>\x3e[undocced nop]
@\x40inc eax
A\x41inc ecx
B\x42inc edx
C\x43inc ebx
D\x44inc esp
E\x45inc ebp
F\x46inc esi
G\x47inc edi
H\x48dec eax
I\x49dec ecx
J\x4adec edx
K\x4bdec ebx
L\x4cdec esp
M\x4ddec ebp
N\x4edec esi
O\x4fdec edi
P\x50push eax
Q\x51push ecx
R\x52push edx
S\x53push ebx
T\x54push esp
U\x55push ebp
V\x56push esi
W\x57push edi
X\x58pop eax
Y\x59pop ecx
Z\x5apop edx
[\x5bpop ebx
\\x5cpop esp
]\x5dpop ebp
^\x5epop esi
_\x5fpop edi
d\x64FS Segment Override
e\x65GS Segment Override
f\x6616 Bit Operand Size
g\x6716 Bit Address Size
h\x68push 0x######## [dword]
i\x69imul reg/mem with immediate to reg/mem
j\x6apush 0x## [byte]
k\x6bimul immediate with reg into reg
l\x6cinsb es:[edi], [dx]
m\x6dinsl es:[edi], [dx]
n\x6eoutsb [dx], dx:[esi]
o\x6foutsl [dx], ds:[esi]
p\x70jo 0x## [byte relative offset]
q\x71jno 0x## [byte relative offset]
r\x72jb 0x## [byte relative offset]
s\x73jae 0x## [byte relative offset]
t\x74je 0x## [byte relative offset]
u\x75jne 0x## [byte relative offset]
v\x76jbe 0x## [byte relative offset]
w\x77ja 0x## [byte relative offset]
x\x78js 0x## [byte relative offset]
y\x79jns 0x## [byte relative offset]
z\x7ajp 0x## [byte relative offset]

After converting instruction we will get Pure Alphanumeric Shellcode:

Alphanumeric Shellcode Execution using C/ASM Program

For more click here
*Feel free to comment below 


Popular posts from this blog

Hacking Windows 10 UWP App: DLL Injection & common Vulnerabilities

I recently started working on  widows 10 Apps( Apps not Applications) security. Before diving deep in hacking terms lets try to understand what's new in Windows 10 UWP( Universal Platform) as compared to old Apps. Lets begin with how apps actually work on windows 10(desktop/tablet). Now windows 10 comes with a container only for running apps inside the isolated environment. By default, /APPCONTAINER(Linker Flag) is off. This option modifies an executable to indicate whether the app must be run in the appcontainer process-isolation environment. Specify /APPCONTAINER for an app that must run in the appcontainer environment—for example, a Windows Store app. (The option is set automatically in Visual Studio when you create a Windows Store app from a template.) For a desktop app, specify /APPCONTAINER:NO or just omit the option. The /APPCONTAINER option was introduced in Windows 8. Now there is no registry entry concept for these app in the System HIVE rather they install they own hiv

SSI Injection Attack

SSIs are directives present on Web applications used to feed an HTML page with dynamic contents. They are similar to CGIs, except that SSIs are used to execute some actions before the current page is loaded or while the page is being visualized. In order to do so, the web server analyzes SSI before supplying the page to the user. The Server-Side Includes attack allows the exploitation of a web application by injecting scripts in HTML pages or executing arbitrary codes remotely. It can be exploited through manipulation of SSI in use in the application or force its use through user input fields. It is possible to check if the application is properly validating input fields data by inserting characters that are used in SSI directives, like:  Code: < ! # = / . " - > and [a-zA-Z0-9] Another way to discover if the application is vulnerable is to verify the presence of pages with extension .stm, .shtm and .shtml. However, the lack of these type of pages does not mean that th

Assignment 01(Enroll TO Offensive-Security Course)

Steps 1:download the page. 2:open fc4.js in your favourite editor and add following lines in it or just replace it with vode given below. 3:then open the download html file in browser and fill the form with your email and a garbage value string. 4:thats it? it will show you the real security string?? yeah but  ...theirs another challenge waiting for you ... :D function fc4me(srvstr) {    if(! || !document.pleazfc4me.securitystring.value) {       alert("Please fill in all the required fields!");       return false;    }    else {       document.pleazfc4me.submit();     }    var t=hexMD5("\x74\x72\x79\x68\x61\x72\x64\x65\x72"+srvstr) alert(t) document.write(t) } Finally Got In :-)