[slf4j-dev] Remote code execution vulnerability in log4j 2.x

[Gary Gregory]

It also can be avoided by not using an old version of Java as Java 8u121
(see https://www.oracle.com/java/technologies/javase/8u121-relnotes.html)
protects against remote code execution by defaulting
"com.sun.jndi.rmi.object.trustURLCodebase" and
"com.sun.jndi.cosnaming.object.trustURLCodebase" to "false".

Gary

On Fri, Dec 10, 2021, 04:36 Ceki Gülcü <ceki at qos.ch> wrote:

>
> Hello all,
>
> You might have heard of a Remote code execution (RCE) vulnerability in
> log4j 2.x, that allows an attacker to execute arbitrary code by
> controlling the contents of a single logged message. While
> vulnerabilities are reported now and then, this vulnerability is totally
> unheard of in its severity.
>
> As for logback, while logback claims to be the successor to log4j 1.x,
> logback is unrelated to log4j 2.x. It does not share code nor
> vulnerabilities with log4j 2.x. More specifically, logback does not
> suffer from aforementioned said RCE vulnerability in any shape or form.
>
> Unfortunately, the vulnerability exists under SLF4J API when log4j 2.x
> is used as the back-end implementation. Given the severity of this
> issue, we  encourage you to consider logback as the preferred back-end
> for SLF4J API.
>
> Also note that logback performs significantly better than log4 2.x.
>
> Please see the benchmark results at:
>
>   http://logback.qos.ch/performance.html
>
> Better yet, run the benchmark yourself.
>
>    https://github.com/ceki/logback-perf
>
> In our opinion, logging libraries need to be reliable first and foremost
> with new features added only with extreme care.
>
> Best regards,
>
> Further references to the RCE vulnerability:
>
>    https://www.lunasec.io/docs/blog/log4j-zero-day/
>    https://twitter.com/P0rZ9/status/1468949890571337731
>    https://github.com/apache/logging-log4j2/pull/608
>
> --
> Ceki Gülcü
>
> Please contact sales at qos.ch for support related to SLF4J or logback
> projects.
> _______________________________________________
> slf4j-dev mailing list
> slf4j-dev at qos.ch
> http://mailman.qos.ch/mailman/listinfo/slf4j-dev
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