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RagingCactus 6 hours ago

As a security person it is tiring to see so many people here either directly claim or at least allude to the claim that this is somehow much less scary because the _published_ exploit does not bypass ASLR. The writeup claims there is a way to reliably bypass ASLR with this attack. And that is a good default assumption I would be willing to believe without evidence.

ASLR is a defense-in-depth technique intended to make exploitation more difficult. In almost all cases it is only a matter of time and skill to also include an ASLR bypass. Both requirements continue being lowered by LLM agents every few weeks. It is only a matter of time (and probably not a lot of time) until a fully weaponized exploit is developed. It may be published, it may also be kept private.

It is straight up wrong to say "if you have ASLR enabled, you're not at any risk from this" and saying this is extremely harmful for anyone that trusts claims like that.

This wrong belief that you shouldn't care about security vulnerabilities because mitigations may make exploitation more difficult has already caused so much harm in the past. Be glad that modern mitigations exist, but patch your stuff asap. If you are a vendor, do not treat vulnerability reports as invalid because the researcher has not provided an ASLR bypass. Fix the root cause and hope mitigations buy you enough time to patch before you get owned.

kro 4 hours ago | parent | next [-]

No remotely reachable vuln should be taken lightly.

At the moment though, the preconditions look odd. I've been using nginx in various constellations for 10 years and never once combined rewrite and set.

buzer 3 hours ago | parent [-]

There can be situations where you set some variables on top level and then override those in the location block with rewrite. These variables could be then used e.g. in log lines or in other "global" contexts.

Not extremely common, but it does happen.

jijji 30 minutes ago | parent | prev | next [-]

yeah when I read these RCE reports about public-facing software that I know about I usually upgrade them within minutes of reading the report that's why I read these reports and you really have to take them seriously because otherwise your machine gets compromised, sooner rather than later... it seems like lately there's been no advance notice on a lot of these RCE exploits that are publicly released, I mean come on guys at least give us a few minutes to upgrade our software before releasing the exploit, it feels like the late 1980s early 1990s when there was no guardrails on disclosure, i.e. all the remotely exploitable sendmail bugs. people who fail to read these reports or read them too late wind up having millions of machines being compromised because of it. currently nginx has about a 39% - 43% share of the public facing web server market today, so its pretty serious.

embedding-shape 5 hours ago | parent | prev | next [-]

> and saying this is extremely harmful for anyone that trusts claims like that.

Kind of feels like the burden is on the one who is reading it though, good luck stopping people from spreading misinformation on the internet, most of them don't even know they're wrong.

What's extremely harmful is trusting random internet comments stating stuff confidently. Get good at seeing through that, and it'll serve you well in security and beyond.

nicce 3 hours ago | parent | prev [-]

> ASLR is a defense-in-depth technique intended to make exploitation more difficult. In almost all cases it is only a matter of time and skill to also include an ASLR bypass. Both requirements continue being lowered by LLM agents every few weeks. It is only a matter of time (and probably not a lot of time) until a fully weaponized exploit is developed. It may be published, it may also be kept private.

I disagree with this take, or I would at least phrase it differently. ASLR is like an extra password you need to guess. It has certain amount of entropy and it is usually stable. Unless vulnerability has a portion that leaks information, ASLR completely mitigates it - or you need a second vulnerability. And that is a different conversation. ASLR can completely mitigate individual vulnerability, but not possibly exploit chain.

I would use the argument of possible second vulnerability that leaks information for making people patch quickly anyway. But exploit chains are risk for all kinds of vulns.