this post was submitted on 31 May 2024

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Federal agency warns critical Linux vulnerability being actively exploited (arstechnica.com)

submitted 5 months ago by [email protected] to c/[email protected]

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[–] [email protected] 114 points 5 months ago (9 children)

It's a privilege escalation.

The vulnerability, tracked as CVE-2024-1086 and carrying a severity rating of 7.8 out of a possible 10, allows people who have already gained a foothold inside an affected system to escalate their system privileges. It’s the result of a use-after-free error, a class of vulnerability that occurs in software written in the C and C++ languages when a process continues to access a memory location after it has been freed or deallocated. Use-after-free vulnerabilities can result in remote code or privilege escalation.

[–] JonnyRobbie 50 points 5 months ago (1 children)

rust mentioned, lets goo

[–] [email protected] 23 points 5 months ago (1 children)

Blazingly fast 🚀

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[–] [email protected] 4 points 5 months ago

This is why least privilege is so important. If one account is compromised it will be harder to compromise others if the original account is isolated.

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[–] [email protected] 32 points 5 months ago (7 children)

Yet another security issue that Rust would solve.

[–] [email protected] 58 points 5 months ago (3 children)

Oh, we heard, Rust is the greatest invention since sliced bread. We heard it already. Like 65534 times.

[–] [email protected] 51 points 5 months ago (2 children)

Like 65534 times.

So close to full 16-bit max. So close...

[–] [email protected] 15 points 5 months ago

Yeah I figured he was going purposely for a memory overflow

[–] [email protected] 7 points 5 months ago (1 children)

Yeah we only need 2 brainRusts more to start seeing some fun.

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[–] [email protected] 24 points 5 months ago (5 children)

Aviation, Health, Space and Car industry have only 3 certified languages that they use. Ada, C and C++. Ada is dying because there are way less young engineers who want to invest their future learning it. Then there is C and C++ but they dont offer memory safety and its really hard to master and its really hard and long (thats what she said) to certify the code when being audited for safety by a tier company.

Rust solves by default (no need to review) like 2/3 of the standard requirements those industries have and are that found in C and C++. Rust will soon be approved in this group by the car industry.

Im not a rust fan, but I have 3 things to say about rust.

Its fun to program like C++ having the peace of mind knowing the compiler is there helping.
You dont feel like youre defusing a bomb like when writing C.
Even though its a fun language to write, its also really hard to master, itd say 2 years to be really proficient with it. There is just so much knowledge.

[–] [email protected] 12 points 5 months ago

Aviation, Health, Space and Car industry have only 3 certified languages that they use. Ada, C and C++.

Rust is automotive certified since over half a year. https://ferrous-systems.com/blog/officially-qualified-ferrocene

[–] [email protected] 4 points 5 months ago (1 children)

Could you explain the "no need to review" part? I do keep hearing good things about Rust.

[–] [email protected] 5 points 5 months ago* (last edited 5 months ago) (2 children)

These industries hire third parties to review c and c++ line per line to make sure it's memory safe. Rust by default forces you to write memory safe code, otherwise it won't even compile. The rust compiler tells where is the problem and what it expects. No only for basic Type errors but also for concurrent code.

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[–] [email protected] 13 points 5 months ago (1 children)

I hate it when people talk about new technologies 🤬

[–] [email protected] 9 points 5 months ago (1 children)

Same. We should head back to ICQ!

[–] [email protected] 8 points 5 months ago (1 children)

eh, still beats Discord as far as I'm concerned

[–] VerseAndVermin 4 points 5 months ago (2 children)

Yeah, but no one will hop on irc or mumble to hang out these days.

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[–] [email protected] 28 points 5 months ago (5 children)

Yet another problem that actually updating your shit - which is trivially easy on enterprise Linux - would fix.

It's part of the 95% of problems solved by actually updating your enterprise Linux host.

[–] [email protected] 5 points 5 months ago (4 children)

unattended-upgrades and forget about it

[–] KISSmyOSFeddit 4 points 5 months ago (1 children)

oops, our third party application broke again

[–] [email protected] 5 points 5 months ago

Never happened to me when set to security.

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[–] [email protected] 10 points 5 months ago (2 children)

Any software can have security issues, including ones written in rust. Just because C/C++ allows one to shoot oneself in the foot doesn't mean it's something that's commonly allowed by anyone with any skill, it's just a bug like anything else. I swear, people advocating rust believe that it's something intrinsic in C/C++ that allows such a thing regardless of what a developer does, and it's getting tiresome.

[–] [email protected] 10 points 5 months ago (1 children)

Of course a good developer can avoid these problems for the most part. The point is that we want the bad developers to be forced to do things a safe way by default.

[–] pathief 7 points 5 months ago

Even good developers make mistakes. It's really nice to catch these mistakes at compile time.

[–] [email protected] 4 points 5 months ago (3 children)

But it is, do you not understand what rust brings compared to these two languages ?

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[–] [email protected] 7 points 5 months ago (1 children)

There are still slight advantages to C that probably will make some devs stick to it in specific cases

[–] [email protected] 15 points 5 months ago

But this isn’t one of them

[–] DacoTaco 5 points 5 months ago (1 children)

Serious question, how would using rust avoid this? Rust still has reference types in the background, right? Still has a way to put stuff on the heap too? Those are the only 2 requirements for reusing memory bugs

[–] sleep_deprived 30 points 5 months ago (13 children)

This is a use-after-free, which should be impossible in safe Rust due to the borrow checker. The only way for this to happen would be incorrect unsafe code (still possible, but dramatically reduced code surface to worry about) or a compiler bug. To allocate heap space in safe Rust, you have to use types provided by the language like Box, Rc, Vec, etc. To free that space (in Rust terminology, dropping it by using drop() or letting it go out of scope) you must be the owner of it and there may be current borrows (i.e. no references may exist). Once the variable is droped, the variable is dead so accessing it is a compiler error, and the compiler/std handles freeing the memory.

There's some extra semantics to some of that but that's pretty much it. These kind of memory bugs are basically Rust's raison d'etre - it's been carefully designed to make most memory bugs impossible without using unsafe. If you'd like more information I'd be happy to provide!

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[–] [email protected] 4 points 5 months ago

The problem is bad programmers. You can write good C code but it takes more effort and security checking. You also can write vulnerable and sloppy Rust code.

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[–] [email protected] 26 points 5 months ago (1 children)

Is there a way to jailbreak an Android phone using this exploit?

[–] [email protected] 9 points 5 months ago (1 children)

You could just unlock the bootloader

[–] [email protected] 40 points 5 months ago (8 children)

Assuming the bootloader is unlockable

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[–] [email protected] 19 points 5 months ago (1 children)

Is this even new?

I thought this already circulated a few months back.

[–] [email protected] 18 points 5 months ago (2 children)

Even Debian stable has already patched it.

[–] [email protected] 13 points 5 months ago* (last edited 5 months ago)

Debian is actually one of the fastest patchers

RHEL on the other hand

[–] [email protected] 5 points 5 months ago

Security patches do the opposite of break stuff

[–] [email protected] 13 points 5 months ago

This is the best summary I could come up with:

It’s the result of a use-after-free error, a class of vulnerability that occurs in software written in the C and C++ languages when a process continues to access a memory location after it has been freed or deallocated.

At the time this Ars post went live, there were no known details about the active exploitation.

A deep-dive write-up of the vulnerability reveals that these exploits provide “a very powerful double-free primitive when the correct code paths are hit.” Double-free vulnerabilities are a subclass of use-after-free errors that occur when the free() function for freeing memory is called more than once for the same location.

The write-up lists multiple ways to exploit the vulnerability, along with code for doing so.

The double-free error is the result of a failure to achieve input sanitization in netfilter verdicts when nf_tables and unprivileged user namespaces are enabled.

Some of the most effective exploitation techniques allow for arbitrary code execution in the kernel and can be fashioned to drop a universal root shell.

The original article contains 351 words, the summary contains 168 words. Saved 52%. I'm a bot and I'm open source!

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