log4shell-tools VS JDK

I'm seeing this as well. While the amount of traffic has certainly decreased compared to the first couple of days after the CVE was announced, https://log4shell.tools is still being used by people every day.

e.g. from log4j. Taken from https://log4shell.tools/

I run tests with https://log4shell.tools, and it seems I'm vulnerable on client side, but my server is safe, which makes sense as I compiled the .jar 2 weeks ago with BuildTools as indicated here https://www.spigotmc.org/threads/spigot-security-releases-%E2%80%94-1-8-8%E2%80%931-18.537204/

You're right, but this has always been the trade off with tools like this. You put some trust in the tool's authors and gain some insight in return. Remember the services that tested for Heartbleed (e.g. https://filippo.io/Heartbleed/)? Fairly similar trade-off, but still these tools were widely used.

If you really don't trust me and have some technical know-how, you can self host the service. It's open source: https://github.com/alexbakker/log4shell-tools.

I can't say I'm feeling the same. Still lots of people testing over at https://log4shell.tools almost a week after this vulnerability became widely known. Plenty of people still discovering they're vulnerable as well. I think it's likely that these are just the people who know they're using log4j. If you're running a black box product from a vendor you'll have no clue you're vulnerable until it's too late.

I have a feeling this vulnerability is going to be with us for years. Shameless plug: I built a tool that assists in detecting whether you're vulnerable to this or the previous CVE: https://log4shell.tools. Just enter the JNDI URI it gives you anywhere you suspect it ends up causing a message lookup in log4j. If log4j does so much as a DNS lookup, this tool will tell you about it.

Done! https://github.com/alexbakker/log4shell-tools

I felt out of the loop, thinking that Zero VM was some kind of new distro for OpenJDK but chasing <https://packages.debian.org/sid/openjdk-22-jre-zero#:~:text=...> to <https://sources.debian.org/src/openjdk-11/11.0.23%2B9-1/debi...> lead me to https://github.com/openjdk/jdk/tree/jdk-22-ga/src/hotspot/cp...

It seems that it's a specific CPU target for the Hotspot JIT for non-mainstream architectures (or for research purposes, as I saw mentioned once)

Completely gutted from the OpenJDK, last I checked. See here for the culprit PR: https://github.com/openjdk/jdk/pull/18688

> Yes, they're changing one aspect of signal handler use to work around this problem. They're not stopping the use of signal handlers in general. Hotspot continues to use signals for efficiency in general. See https://github.com/openjdk/jdk/blob/9059727df135dc90311bd476...

This whole thread is about SIGSEGV, and specifically their SIGSEGV handling. However, catching normal signals is not about efficiency.

Some of their exception handling is still odd: There is no reason for a program that receives SIGILL to ever attempt continuing. But others is fine, like catching SIGFPE to just forward an exception to the calling code.

(Sure, you could construct an argument to say that this is for efficiency if you considered the alternative to be implementing floating point in software so that all exceptions exist in user-space, but hardware floating point is the norm and such alternative would be wholly unreasonable.)

> The wonderful thing about choosing not to care about facts is having whatever opinions you want.

I appreciate the irony of you making such statement, proudly thinking that your opinion equals fact, and therefore any other opinion is not.

This discussion is nothing but subjective opinion vs. subjective opinion. Facts are (hopefully, as I can only speak for myself) inputs to both our opinions, but no opinion about "good" or "bad", "nasty" or not can ever be objective. Objective code quality does not exist.

I remember talking to Brendan about the PreserveFramePointer patch during my first months at Netflix in 2015. As of JDK 21, unfortunately it is no longer a general purpose solution for the JVM, because it prevents a fast path being taken for stack thawing for virtual threads: https://github.com/openjdk/jdk/blob/d32ce65781c1d7815a69ceac...