Movfuscator – A single-instruction C compiler

Yes, but you probably need something more sophisticated than just running the same instruction type over and over again: https://dl.acm.org/citation.cfm?id=2744295.2724718

slacka• 10 years ago

This wouldn't do any noticeable damage. Modern CPUs have excellent thermal management. As far a wear goes, a hot spot in chip would in theory slightly decrease the long life span of a CPU.

If you expanded your question to hardware in the computer, then yes you can easily cause damage. BIOS’s can be flashed to make the system unbootable or overclock/stress components. Back in the bad old days of Linux, you could easily damage your monitor with the wrong xorg.conf settings.

Your question got me thinking what’s the MTBF of modern CPUs? My google-fu failed me finding any reliable source of this, but I’m sure it’s long, 10+ years.

TazeTSchnitzel• 10 years ago

Probably not for MOV, given x86 uses it a heck of a lot anyway, so surely processors are already equipped to handle it.

amelius2• 10 years ago

Well, I think this can be answered by considering that even under normal conditions there are transistors that are used as much as in your hypothetical scenario. For example, the instruction decoding logic is invoked for every instruction. Since all logic transistors are the same (afaik), I don't think that using one type of instruction would significantly reduce the life-time of your CPU.

koytch2• 10 years ago

Uhm, not really, but you might make 20 smaller ones.

http://x86.renejeschke.de/html/file_module_x86_id_176.html

mappu• 10 years ago

You should also regularly rotate your CPU in its socket, to ensure all the cores wear evenly.

mighty_atomic_c• 10 years ago

Seems like it would give a large performance penalty. I don't get it.

detaro2• 10 years ago

It's a joke/demonstration that it is possible, not something you're supposed to use.

posterboy• 10 years ago

Obfuscation is surely used in malware.

One instruction set computers (OISC) are more than a joke, I suppose, but I didn't dig far into theoretical computer science and can't say, what's important about them.

I read a comment the other day, that stipulated neurons would be akin to massively parallel single instruction computers.

hulahoof2• 10 years ago

There is a good talk that accompanies the code

caretStick• 10 years ago

source?

aub3bhat• 10 years ago

Could this be used for creating a ROP Gadget that overcomes ASLR on 64 bit machines?

l_zzie• 10 years ago

How does it get past aslr? You still need to find addresses of the movs, don't you?

isuckatcoding• 10 years ago

ELI5 please. What does this mean for a developer?

bluedino• 10 years ago

Nothing - it's simply an intellectual exercise. It uses the MOV instruction exclusively to create a working program.

Further reading - http://www.cl.cam.ac.uk/%7Esd601/papers/mov.pdf

0x0• 10 years ago

It might find some use in DRM, malware, and other exploits as it would make reverse engineering/decompiling/analysis somewhat more challenging.

haberman• 10 years ago

Someone made something very clever, but it has no practical usefulness whatsoever. It is an interesting intellectual exercise. It's also very impressive that they could pull this off.

SilasX• 10 years ago

I would think it has some practical use as research in OISC (one-instruction set computing) processors, which are like the RISC model (do a smaller set of instructions so you can do them faster) on steroids.

lucb1e2• 10 years ago

No practical usefulness? It seems rather great for obfuscation, be it for evil (viruses) or good (license key verification -- which is deemed 'good' merely because they're legal, not because they're not a pain in the arse).

jakub_h• 10 years ago

You can stop worrying about branchless code and have it generated automatically! ;)

danjoc• 10 years ago

And for the minimalist, the zero-instruction C compiler

https://github.com/jbangert/trapcc

toolslive• 10 years ago

just what I need for my next virus

tbodt• 10 years ago

How do we do arithmetic if we can only do movs?

I know! Lookup tables!

LightMachine• 10 years ago

Not sure I understand how that is possible. How would you implement a boolean "and" with only "mov"? If you can only move stuff around, how do you read and compare things?

__s• 10 years ago

If you look at turing machines they're pretty minimal, just a state machine reading/writing state on a tape

Repo includes a good set of slides: https://github.com/xoreaxeaxeax/movfuscator/blob/master/slid...

Indirect memory accesses serve for conditional execution

Here's the macro for boolean and: https://github.com/xoreaxeaxeax/movfuscator/blob/master/poc/...

projectdp• 10 years ago

Saw this recently after reviewing some Defcon 23 videos. The author goes into detail about how it's working and some other fun stuff regarding anti-reverse-engineering.

2015 DEFCON 23 - Chris Domas - Repsych: Psychological Warfare in Reverse Engineering https://www.youtube.com/watch?v=HlUe0TUHOIc

And a paper by him: https://www.cl.cam.ac.uk/~sd601/papers/mov.pdf

_c_• 10 years ago

Since we are joking, assuming that the MOV instruction exists on many CPU's, could the input for this compiler be considered a needed "portable assembly language"?

http://cr.yp.to/qhasm/20050129-portable.txt

2opdude• 10 years ago

The MOV mnemonic is more like a family of instructions, isn't it?

Not knowing anything about GPU programming, isn't it similar to Movfuscator in some respects? Both branches are taken and run simultaneously?

amelius2• 10 years ago

But MOV is not really a single instruction. I would be more impressed by a single opcode compiler.

Movfuscator – A single-instruction C compiler

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