> For the complete documentation index, see [llms.txt](https://jedi.gitbook.io/jedi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jedi.gitbook.io/jedi/ctf-archive/downunderctf-2025/zeus-100-pts.md).

# zeus (100 pts)

### Description

Dear CSI,

To Zeus Maimaktes, Zeus who comes when the north wind blows, we offer our praise, we make you welcome!

Regards,\
jzt

#### Attachments

* [zeus](https://storage.googleapis.com/downunderctf-2025-noctf-files/noctf-files/e8CmMDbnsXs3EcmKAxYrW?X-Amz-Algorithm=AWS4-HMAC-SHA256\&X-Amz-Credential=GOOG1ELBSKCSEHWDHBGZCFZBP3RXLJBHVAZJTTYKCMYMRJRM6O5N35G46S26H%2F20250720%2Fauto%2Fs3%2Faws4_request\&X-Amz-Date=20250720T145000Z\&X-Amz-Expires=1200\&X-Amz-SignedHeaders=host\&X-Amz-Signature=562320cd11bce5b45150cd4394f84615f011c5ed190cfcf7a734924dc27ff90f)

### Solution

This is a pretty easy challenge. We were given a binary file named **zeus**

```
jedi@aqua: /mnt/d/CTF/ductf/beginner
$ file zeus                                                                                                              
zeus: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=95542c1d888f30465172c1c77dd1eef1109b4c29, for GNU/Linux 3.2.0, not stripped
```

After that, we can try to open it with IDA

<figure><img src="/files/rcRDb624eGsTDOBcFKyV" alt=""><figcaption></figcaption></figure>

From the main function of the binary, we see that there is some data that is saved in several variable, and a function named xor, with the key is **Maimaktes1337**

There is also a conditional if that is checking 3 things : is there exist 3 arguments? is the second argument is "-invocation"? is the third argument is the string "**To Zeus Maimaktes, Zeus who comes when the north wind blows, we offer our praise, we make you welcome!"** ?

There are 2 ways to solve this

1. Use the parameter invocation
2. Xor the data manually

Because i wanna keep it simple, we can just use the run this to get the flag

```
./zeus -invocation 'To Zeus Maimaktes, Zeus who comes when the north wind blows, we offer our praise, we make you welcome!'
```

### Flag

<figure><img src="/files/mDFEwYB6nAewieXJDf21" alt=""><figcaption></figcaption></figure>

`DUCTF{king_of_the_olympian_gods_and_god_of_the_sky}`


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