> For the complete documentation index, see [llms.txt](https://wintertia.gitbook.io/ctf/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wintertia.gitbook.io/ctf/writeups-2025/acectf-2025/underflow.md).

# !Underflow

"Binary Exploitation"

{% hint style="danger" %}
My blog has migrated to <https://wintertia.pages.dev/> ! This Gitbook will no longer be maintained.
{% endhint %}

> Something simple to warm you up.

{% file src="/files/ppsKj2tuxtnmZDPGNDGq" %}

Given a binary called "exploit-me", we decided to decompile with Ghidra.

![image](https://hackmd.io/_uploads/rymjzR0qkl.png)

Looking at the function list, we were curious about the `print_flag` function so we decided to take a look further.

![Screenshot 2025-02-27 163105](https://hackmd.io/_uploads/SyRDfCCcJx.png)

The flag was just written in plain text: `ACECTF{buff3r_0v3rfl3w}`