Okay, I found the answer. I gave this a go but failed. I think my progress as a spy will be limited to mixing my martinis shaken, not stirred. Answer is Pr0t3ct! Explore these posts. Find out how. Have you been to the Geek Native Chat Portal? Notify of. Oldest Newest Most Voted. Inline Feedbacks. Just sayin' Offline. Sdfdsffdfdfd Offline. What a terrible clue!
Get the comment from the png file. I used python. Jerzzy Offline. Wako Offline. Reply to Jerzzy. Reply to Wako Aef Offline. Troll Offline. Reply to Aef. Great pension and the ability to strike if they try and take it away from you?
My customers love the new look and are always complimenting it so I cannot thank them enough. We wanted to modernise our branding but keeping a traditional homely feel that our customers are used to when visiting our hotel. The team at Crack IT Solutions were excellent and understood exactly what we wanted and worked with us to achieve this.
The attention to detail and constant feedback gave us confidence in what they were doing and we are very happy with the finished design of the website. The app looks great and is very easy to use and we could not be happier with it. Thank you for everything you have done and will be sure to recommend to anyone building mobile phone apps in future. So, promptly, I got onto the job and it was surprisingly easy and I imagine it will be for most people who can reverse engineer and has experience doing so.
Click read more to see how I did it, but I suggest you have a good attempt beforehand. I sat around for a good few minutes just reading the hex. However, I noticed something! So shoving it into a disassembler, I get some nasty x86 code. After whimpering at the sight of it, I cracked on and reversed engineered the code into lovely C.
But there was something missing! In the x86, it does a near call which pushes the return address onto the stack. This sneaky little program then pops this off the stack and then sets it as the new top of stack. After the return address, a sneaky pop loads 0x, the last 32 bit value in the file, and then checks it does equal that.
Then, it does another pop… wait a second. Solving this stage will reveal the final stage of the challenge. The final stage is a reverse engineering challenge.
An executable file can be downloaded from the location revealed in stage 2. This executable parses a licence file - if it gets given a correct input, the challenge is revealed to be over, and a link to the 'success' page is provided to the participant.
We included a number of ways that this stage could be solved, as we are interested to see how people would attack the problem - coming up with innovative solutions to seemingly impossible problems is the day job at GCHQ. For example, there has been some comment by security experts on the fscanf buffer overflow that we included in this executable - one option to solving the problem would be to use this overflow to skip over certain checks in the executable.
Other alternatives for this stage involved breaking the weak crypt, patching the executable directly to bypass the check, or analysing the assembly instructions and realising that this was all a complete diversion.
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