Introduction Hi all, Over the course of the past few weeks ago, I received a number of “emergency” calls from some relatives, asking me to look at their computer because “things were broken”, “things looked different” and “I think my computer got hacked”. I quickly realized that their computers got upgraded to Windows 10. We […]
In this post, we’ll look at an application reversing challenge from HTS (hackthissite.org) resembling a real-life protection scheme.
Put simple, the program creates a key for your username, and compares it to the one you enter.
The goal of the HTS challenge is to create a key generator, but I just want to demonstrate how to retrieve the password.
About 3 months after finishing my previous exploit writing related tutorial, I finally found some time and fresh energy to start writing a new article.
In the previous tutorials, I have explained the basics of stack based overflows and how they can lead to arbitrary code execution. I discussed direct RET overflows, SEH based exploits, Unicode and other character restrictions, the use of debugger plugins to speed up exploit development, how to bypass common memory protection mechanisms and how to write your own shellcode.
While the first tutorials were really written to learn the basics about exploit development, starting from scratch (targeting people without any knowledge about exploit development) you have most likely discovered that the more recent tutorials continue to build on those basics and require solid knowledge of asm, creative thinking, and some experience with exploit writing in general.
Today’s tutorial is no different. I will continue to build upon everything we have seen and learned in the previous tutorials. Today I will talk about ROP and how it can be used to bypass DEP (and ASLR)…