Log4j mitigation

Tue Dec 14 17:30:55 UTC 2021

Another handy one to find where it's hiding, since it can be bundled inside
other JARs:
find / -name *.jar | xargs strings -f | grep -i log4j

On Tue, Dec 14, 2021 at 6:57 AM Doug McIntyre <merlyn at geeks.org> wrote:

> On Mon, Dec 13, 2021 at 11:38:04AM -0800, Owen DeLong via NANOG wrote:
> > > On Dec 11, 2021, at 04:11 , Nick Hilliard <nick at foobar.org> wrote:
> ...
> > > https://logging.apache.org/log4j/2.x/security.html
> > >
> > > 1. upgrade log4j to 2.15.0 and restart all java apps
> > > 2. start java with "-D log4j2.formatMsgNoLookups=true" (v2.10+ only)
> > > 3. start java with "LOG4J_FORMAT_MSG_NO_LOOKUPS=true" environment
> variable (v2.10+ only)
> > > 4. zip -q -d log4j-core-*.jar
> org/apache/logging/log4j/core/lookup/JndiLookup.class
> > >
> > > There's a lot of scanning going on at the moment, so if you have an
> exposed java instance running something which includes log4j2, you may
> already be compromised.
> > >
> > > Nick
> >
> > Alternatively, this incantation solved the problem on my linux server:
> >
> > rpm -e log4j12 ant-apache-log4j log4j
>
>
> There are many software setups that bundle their own log4j.jar without
> bothering to go through the OS package manager....
>
> $ rpm -qa | fgrep log4j
> $
>
> $ find / -name log4j*jar
> ....system/log4j/log4j/log4j/1.2.17/log4j-1.2.17.jar
>
> (obviously an old system due to the commands used and version found,
> and nor will it get patches available because of vendor...).
>
> Sorta like playing whack-a-mole with jquery.js (another package with
> lots of security history that seems to be copied _everywhere_ without
> registring it with the OS package manager).
>
> So, the exercise becomes _finding_ the software that uses it, and then
> doing the configs that defang JNDI everywhere you find it.
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.nanog.org/pipermail/nanog/attachments/20211214/8a183777/attachment.html>