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I Can Crack Your App With Just A Shell (And How To Stop Me)

kswizz.com

91–93 of 93 posts

Re: I Can Crack Your App With Just A Shell (And How To Stop Me)

#91
post #74

Earlier quoted context omitted.

As someone who has been down this path I can offer a couple of comments. 1. Crashing or crippling the program indeed has an obvious negative PR side-effect. However it can be mitigated by inducing a very exotic crash, something like "Division by zero" or better yet - "Illegal Instruction", which would clearly point at mangled code being at fault. Also stick a thread titled "Illegal Instruction" in Support forums, exp…

"Division by zero" and "illegal instruction" don't sound exactly exotic. And even with a proper error message, a crshy app is perceived as defective. Assuming that the users will google the message is a long shot. I'd assume that most would simply show your binary the trash can / recycle bin / dev/null and move on. Your second strategy sounds very interesting. Especially because you can A/B test the licensing period…

> I'd assume that most would simply show your binary the trash can / recycle bin / dev/null and move on.

And this is totally fine. These are the users who consciously decided to run hacked version instead of the original. Why they would do that is beyond me, but I am damn sure I will not ever see a one of them as my customer.

The only drawback is that of that them making a fuss because of the crashes and this is easily mitigated as per above. You just have to keep in mind that checking Referrers in website logs and following up on any product related discussions out there should also be a routine. So for anyone complaining about the crashes - post a link to the support article explain why and when it does that.

> However, I don't understand how it helps paying customers.

Primarily by not needing to spend any time on support/PR issues stemming from the use of hacked versions.

Re: I Can Crack Your App With Just A Shell (And How To Stop Me)

#92
post #53
post #20

The most stealth cracking countermeasure I ever witnessed was the application would XOR some of its UI messages with the hash sig of the application binary file, so if you edited the application binary file directly the crack seemed to work just fine ... but then the application would gradually go insane. The cracker who finally posted a working crack was impressed with how simple and devious the countermeasures were…

Brilliant, but be careful about this. There was an article here years ago about an indie game developer who put tons of different piracy checks all throughout his game. He was pretty clever, and made it so that several didn't activate until partway through the levels — that way the crackers might miss them. Also, he didn't show any "pirated copy detected!" messages, which would have made the checks trivial to find. I…

DRM = functionally indistinguishable from broken

Re: I Can Crack Your App With Just A Shell (And How To Stop Me)

#93
post #20

The most stealth cracking countermeasure I ever witnessed was the application would XOR some of its UI messages with the hash sig of the application binary file, so if you edited the application binary file directly the crack seemed to work just fine ... but then the application would gradually go insane. The cracker who finally posted a working crack was impressed with how simple and devious the countermeasures were…

I am almost certain Ableton Live for the mac does something like this. It is a piece of music production/performance software. It will appear to function normally, but the audio engine will gradually begin to fail in increasingly ugly ways, especially when you use plugins. It usually starts doing this after a few weeks or months of regular uninterrupted use. Considering this app is used by professional musicians to p…

I think that Ableton does this too. Almost every month or few weeks it would reliably crash.
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