

Exploit Linux Machines Through Fun Challenges - turnersr
http://exploit-exercises.com/

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EthanHeilman
* I haven't played with exploit-exercises yet (definitely will when I get some downtime), but I've had a blast solving the challenges at <http://io.smashthestack.org:84>. They are hosted so no need to download VMs. They have a several more here that I haven't played with: <http://smashthestack.org/>

* I recently came across a computer security course which used CTF virtual machines for an assignment (you can download the VM and see how you do against Tufts University students): <http://www.cs.tufts.edu/comp/116/assignments/a04.php>

* Offensive Security's "Penetration Testing with BackTrack" (PWB) course uses a series of CTF challenges as the final exam.

* Any recommendations on any encryption challenges in this style?

We are seeing a return to the old guild system of masterpieces as proof of
ability and learning aid. I couldn't be happier. I'd love to see a mash up
between stackoverflow's gamification and Offensive Security
certification/teaching process.

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ahel
upvote for the smashthestack.org link. really interesting place.

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jiggy2011
I've never really had much luck with stuff like this.

Whenever I have tried to write code in the C to be deliberately vulnerable and
have tried to overwrite memory etc it never seems to work in the way I expect.

For example I will have two arrays that are contiguous in memory (checking
this with gdb) and I will then write a big set of values into one array that
should overflow into the other. Then try and do something like print the
values that should have been overflowed into but I often find I either get a
segfault or that the values that are printed are actually the correct values
assigned the the array that should be overwritten.

I haven't tried these specific puzzles with the VMs though. I always do -fno-
stack-protector when compiling but I don't know if there is some other
security mechanism that could be stopping it from working?

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ZephyrP
-fno-stack-protector does a number of things that interfere with "standard" smashing of the stack, You'll learn a lot if you keep stack protections in place!

Also, be sure to turn off Write^Execute memory pages and ASLR as another
commenter has suggested.

Alternatively, you could try your hand at defeating these protection
mechanisms yourself with a number of (relatively) newfangled techniques.

JITSpray - <http://dsecrg.com/pages/pub/show.php?id=22> ROP -
<http://cseweb.ucsd.edu/~hovav/talks/blackhat08.html>

and more!

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SoftwareMaven
This looks awesome. I've taken a large interest in security over the last
couple years and am always looking for ways to increase my knowledge in this
space (FWIW, the Stanford crypto course has been great so far). This will be a
good follow-on to that.

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chuckbot
What exactly does the getflag command do? I seems like I can do all the levels
anyway, so it doesn't seem to enable the next level.

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haberman
Awesome! I was always jealous of people who had problem sets like this in
their CS curriculum.

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why-el
I think the curricula you are talking about are surprisingly few. In fact I
think this website offers more interesting things than my Security class did.
:)

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spydum
I am _really_ digging the uptick in CTF related posts! Keep 'em coming!

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mituljain
it's down :/

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aw3c2
Works for me. Anyways, the torrent for the beginner VM is
magnet:?xt=urn:btih:77cfd777dd287da30dcdc5c82aa72f0ffb6c67eb

