> For the complete documentation index, see [llms.txt](https://kos0ng.gitbook.io/ctfs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kos0ng.gitbook.io/ctfs/write-up/2023/flare-on-10/challenge-1-x.md). # Challenge #1 - X ### Description Welcome to the 10th Annual Flare-On Challenge! Statistically, you probably won’t finish every challenge. Every journey toward excellence starts somewhere though, and yours starts here. Maybe it ends here too. This package contains many files and, I can’t believe i’m saying this, click the one with the “.exe” file extension to launch the program. Maybe focus your “reverse engineering” efforts on that one too. ### Solution Since the pin only 2 digits, i bruteforce it manually.

Another solution is by decompiling the program using dnspy. At the time of competition i used old version of [dnspy](https://github.com/dnSpy/dnSpy) which didn't produce the actual code. But after competition i notice that there is a new version of [dnspy](https://github.com/dnSpyEx/dnSpy) that maintained by another user. Download the latest version from the repository and then decompile the X.dll.

By executing the program we know that the flag will be shown if we input valid 2 digits and click the "lock" button. Based on the function structure name, the function lockButton\_Click will be the called function when we click the "lock" button. So by looking at decompiler result we can get the flag directly in plaintext. Flag :