Rating: 3.0

Problem:
JVM
(rev, 25 points)

"Bytecodes everywhere, reverse them."

Attachment
rev25_3100aa76fca4432f.zip

Solution:
In the zip file there was a .class file. It can be immediately recognized that this is a Java .class file (the name of the challenge "JVM" is also a hint as it stands for "Java Virtual Machine"), and while the .class file is just the binary, Java (like C# or VB.NET) can easily be decompiled because of how highly detailed the bytecode is. Pop this into a decompiler such as http://www.javadecompilers.com/, and we'll get the following source:

public class EKO {
    public static void main(String[] arrstring) {
        int n = 0;
        for (int i = 0; i < 1337; ++i) {
            n += i;
        }
        String string = "EKO{" + n + "}";
    }
}

If we run the source, we'll get our flag.

Flag: EKO{893116}