Um, I'm trying to write a course review, but I'm really having a hard time. I don't know how to express it. I solved a lot of problems like CTF, but I only understood the download vulnerability briefly. Even if I searched and understood it on my own, it was hard to draw the big picture. However, before taking this course, I had some doubts and arrogant thoughts like, "Is this just some kind of course?" (I guess I understand most of it!) I guess I can call it pride! I'm sorry to the instructor..ㅠ I knew some parts in the first few parts! But as I went further and further back, I started to see umm???????? ???????????? ???????? and I suddenly thought, "Ah!" I watched and ... There may be some people who think, "There's only one download vulnerability ~ There's only one upload vulnerability ~" and "Oh, there are really no reviews, so it must not be that good ~"! But! It includes really advanced lectures that you can't hear in those lectures! (This is not a criticism of other lectures! It means that it was that good of a lecture!ㅎㅎ) I understand that you can get a refund if you don't receive the practice materials. (According to Inflearn policy? Check the details!!) I think it would be good to listen to it. Disadvantages: There were none! ㅎㅎㅎ