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https://issues.apache.org/jira/browse/LOG4J2-3221?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17461056#comment-17461056
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Corey Puffalt edited comment on LOG4J2-3221 at 12/16/21, 9:48 PM:
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Can anyone confirm whether using log4j-to-slf4j leaves us open to this
vulnerability? The
[documentation|https://logging.apache.org/log4j/2.x/log4j-to-slf4j/index.html]
states that "the Log4j 2 Messages must be formatted before they can be passed
to SLF4J." which makes me think it would be vulnerable but I performed some
manual testing on an app using this library and wasn't able to reproduce.
Thoughts?
was (Author: cpuffalt):
Can anyone confirm whether using log4j-to-slf4j? The
[documentation|https://logging.apache.org/log4j/2.x/log4j-to-slf4j/index.html]
states that "the Log4j 2 Messages must be formatted before they can be passed
to SLF4J." which makes me think it would be vulnerable but I performed some
manual testing on an app using this library and wasn't able to reproduce.
Thoughts?
> JNDI lookups in layout (not message patterns) enabled in Log4j2 < 2.16.0
> ------------------------------------------------------------------------
>
> Key: LOG4J2-3221
> URL: https://issues.apache.org/jira/browse/LOG4J2-3221
> Project: Log4j 2
> Issue Type: Bug
> Reporter: Lucy Menon
> Priority: Major
> Fix For: 2.16.0
>
>
> The mitigation advice for CVE-2021-4428 suggests that for Log4j > 2.10.0 and
> < 2.15.0, the vulnerability can be avoided by setting
> -{{{}Dlog4j2.formatMsgNoLookups=true{}}} or upgrading to 2.15.0. However,
> many users may not be aware that even in this case, lookups used in layouts
> to provide specific pieces of context information will still recursively
> resolve, possibly triggering JNDI lookups. In order to avoid
> attacker-controlled JNDI lookups, users must also either:
> * Ensure that no such lookups resolve to attacker-provided data
> * Ensure that the the JndiLookup class is not loaded
> * Upgrade to log4j2 2.16.0 (untested)
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