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Copy Fail

copy.fail

181–190 of 545 posts

Re: Copy Fail

#181

LPE = local privilege escalation Too many darn acronyms. This one wasn't too hard to figure out from context but I wish people would define acronyms before using them!

Good writing for a broad audience requires it. Unfortunately the LLMs don't tend to adopt this guideline.

it’s a CVE write up; the audience for these knows what an LPE is.

Re: Copy Fail

#182
post #92

For mitigation, the page currently basically just says: > Update your distribution's kernel package to one that includes mainline commit a664bf3d603d But it isn't very clear to me what Kernel version you can expect that to be in. For Arch/CachyOS, the patch seems to be included in 6.18.22+, 6.19.12+ and 7.0+. If you're on any of the lower versions in the same upstream stable series, you're likely vulnerable right now…

On a git repo that has as remotes https://github.com/torvalds/linux.git https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git as remotes: running a search for commit a664bf3d603d's commit message: git log --all --grep 'crypto: algif_aead - Revert to operating out-of-place' '--format=%H' | xargs -I '{}' git tag --contains '{}' | sort -u outputs these tags as having the fix: v6.18.22 v6.18.23 v6.18.24 v6.18.…

distros might also apply patches to their own packages, so this isn't a perfect signal (i.e. if you have one of those versions, you almost certainly have the fix, but if you don't, it might still be fixed but you'll need to check the distro's package information to know for sure).

Re: Copy Fail

#183

For this crowd, I highly suggest checking out the technical writeup https://xint.io/blog/copy-fail-linux-distributions

This has frustratingly low information density for a technical writeup. The LLM output on the marketing page is whatever, but here it really feels like my time isn’t being respected.

Re: Copy Fail

#184
Quickly dove into this.

1. Yes, it's real.

2. Current chain can write any arbitrary content to any user-readable file (into the page cache).

3. Current chain relies on an available target suid binary that you can open() as a lowpriv user.

4. Current exploit relies on that binary being /bin/su and then being able to execve(/bin/sh, 0, 0) (which doesn't work on alpine, etc.). The former is easily replaced in the code. The latter needs a rebuilt payload ELF (also easy).

5. The authors say they have other chains (including ones that allow container escapes). I believe them.

6. A mildly de-minified PoC for Alpine with a new payload ELF is at hackerspace[pl]/~q3k/alpine.py . You'll need /bin/ping from iputils. This should be now somewhat reliable on any distro that has a `/bin/sh` and any setuid-and-readable binary (you'll just need to find it on your own).

Re: Copy Fail

#186

Earlier quoted context omitted.

ugh sorry should be fixed. There was some scrambling to get more info together to explain the issue (and yes, obviously marketing), so there are some minor mistakes. Thanks for pointing it out!

> obviously marketing Why marketing though?

because we're a company and we want to make money to continue to fund cool research, and help our customers secure their software :)

Re: Copy Fail

#187

Earlier quoted context omitted.

ugh sorry should be fixed. There was some scrambling to get more info together to explain the issue (and yes, obviously marketing), so there are some minor mistakes. Thanks for pointing it out!

> obviously marketing Why marketing though?

Resume-driven development

Re: Copy Fail

#188
post #121
post #90

Earlier quoted context omitted.

I don't see it as fetishizing byte count. I think of it as a proxy measure for how complicated or uncomplicated the exploit might be. They could just as well have said "we can do it in 3 lines of python" or "the Shannon entropy of the script implementing the exploit is really small" and I would have interpreted it similarly. Where do you see this "fetishizing" happening most often? It's a strange thing to counter-fet…

> I think of it as a proxy measure for how complicated or uncomplicated the exploit might be. From a Busy Beaver, 256-bytes compo, or Dwitter perspective, 732 bytes isn’t really that meaningful. And the sample exploit is even optimizing the byte size by using zlib compression, which doesn’t make much sense for the purpose. It just emphasizes the byte count fetishization.

Again, I think the point is that compressed size is a reasonable measure of the inherent complexity of a program. I'm a crap mathematician, but I believe that is a fundamental concept in information theory.

Re: Copy Fail

#189
post #127
post #44

Earlier quoted context omitted.

I have no idea about this page, but Theori/Xint has a staff of veterans, they are a serious thing.

Dropping a public exploit on github before distros have patches available isn't very cool, or is that just how veterans roll these days?

mainline was patched a month ago

Re: Copy Fail

#190
Good thing nobody is silly enough to let fully autonomous AI agents run as regular users on these affected operating systems. That could be disastrous given a zero day prompt injection technique.
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