# Dirt

## Background


## Find the flag

**In the challenge's description, we can download an attachment. Let's download it:**


```shell
┌[root♥siunam]-(~/ctf/KnightCTF-2023/Misc/Dirt)-[2023.01.21|13:42:50(HKT)]
└> file dirt.zip
dirt.zip: Zip archive data, at least v1.0 to extract, compression method=store
```

**It's a `zip` archive file. We can `unzip` that:**
```shell
┌[root♥siunam]-(~/ctf/KnightCTF-2023/Misc/Dirt)-[2023.01.21|13:42:52(HKT)]
└> unzip dirt.zip
Archive: dirt.zip
creating: challenge/
creating: challenge/}/
creating: challenge/}/s/
creating: challenge/}/s/r/
creating: challenge/}/s/r/3/
creating: challenge/}/s/r/3/d/
creating: challenge/}/s/r/3/d/l/
creating: challenge/}/s/r/3/d/l/0/
creating: challenge/}/https://siunam321.github.io/ctf/KnightCTF-2023/Misc/Dirt/s/r/3/d/l/0/f/
creating: challenge/}/s/r/3/d/l/0/f/_/
creating: challenge/}/s/r/3/d/l/0/f/_/3/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/{/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/{/F/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/{/F/T/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/{/F/T/C/
creating: challenge/}/s/r/3/d/l/0/f/_/3/d/1/5/n/1/_/s/r/3/d/l/0/f/{/F/T/C/K/
```

**Oh! Looks like we found the flag??**
```
}sr3dl0f_3d15n1_sr3dl0f{FTCK
```

**However, it looks like it's reversed. Let's use `rev` to reverse it back:**
```shell
┌[root♥siunam]-(~/ctf/KnightCTF-2023)-[2023.01.21|13:44:58(HKT)]
└> echo '}sr3dl0f_3d15n1_sr3dl0f{FTCK' | rev
KCTF{f0ld3rs_1n51d3_f0ld3rs}
```

Nice! We found the flag!


- **Flag: `KCTF{f0ld3rs_1n51d3_f0ld3rs}`**

# Conclusion

What we've learned:

1. Unziping File & Reversing Strings

Original writeup (https://siunam321.github.io/ctf/KnightCTF-2023/Misc/Dirt/).