# Chandi Bot 4
- 183 Points / 147 Solves
## Background
Can you beat the bot?
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225337.png)
## Find the flag
In this challenge, we need 3 commands: ***`/balance` to check how many point we have, `/rps` to play "Rock Paper Scissors" to gain points, `/dad` to gain 1 point, `/buy-flag` to buy flag for 10000 points***
**First, let's check our balance:**
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225541.png)
We got 0 point.
**Then, gain 1 point by using `/dad` command:**
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225613.png)
**Next, use `/rps` to play "Rock Paper Scissors":**
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225700.png)
Hmm... we can't wager 0 points...
I wonder can we go negative points:
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225747.png)
Ohh!! We can! And we gain 1 point!!
**Let's use that logic vulnerbility to gain 9999999 points!!**```/rps choice:Rock wager:-9999999```
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401225855.png)
Boom! We have 10000001 points!!
**Finally, we can use `/buy-flag` command to buy the flag!**
![](https://raw.githubusercontent.com/siunam321/CTF-Writeups/main/RITSEC-CTF-2023/images/Pasted%20image%2020230401230008.png)
- **Flag: `RS{TWO_NEGATIVES_DO_MAKE_A_POSITIVE}`**
## Conclusion
What we've learned:
1. Exploiting Logic Vulnerability