Re: Log4j mitigation

[Owen DeLong via NANOG <nanog () nanog org>]

Thanks… That did find some additional packages hiding this scourge (about a dozen or so packages,
around 100 packages removed after the dependency chains were resolved).


> On Dec 14, 2021, at 09:30 , Tyler Conrad <tyler () tgconrad com> wrote:
>
> 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

If you’re on fedora, it can be useful to pipe the output of that to
        cut -f 1 -d : | xargs rpm -q —whatprovides
which will give you the package names responsible for the files in question.

One of the ones I discovered required quite a number of eclipse-* packages to be removed.

Of the things that were found, there wasn’t anything I cared enough about keeping, so I’m
still inclined to believe that rpm-e is the best solution to this problem at this point.

Owen


> On Tue, Dec 14, 2021 at 6:57 AM Doug McIntyre <merlyn () geeks org <mailto:merlyn () 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 () foobar org <mailto:nick () foobar org>> wrote:
> ...
> > > https://logging.apache.org/log4j/2.x/security.html <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.