nanog mailing list archives
Re: Log4j mitigation
From: Owen DeLong via NANOG <nanog () nanog org>
Date: Tue, 14 Dec 2021 12:05:52 -0800
On Dec 14, 2021, at 06:54 , Doug McIntyre <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> 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. NickAlternatively, this incantation solved the problem on my linux server: rpm -e log4j12 ant-apache-log4j log4jThere 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.
YMMV… Find didn’t find anything named log4j\*jar after I did my rpm -e. Owen
Current thread:
- Re: Log4j mitigation, (continued)
- Re: Log4j mitigation Karl Auer (Dec 13)
- RE: Log4j mitigation Jean St-Laurent via NANOG (Dec 13)
- Re: Log4j mitigation A Crisan (Dec 13)
- Re: Log4j mitigation Mike Hammett (Dec 13)
- Re: Log4j mitigation Karl Auer (Dec 13)
- Re: Log4j mitigation Andy Ringsmuth (Dec 13)
- Re: Log4j mitigation Doug McIntyre (Dec 14)
- Re: Log4j mitigation Tyler Conrad (Dec 14)
- Re: Log4j mitigation Owen DeLong via NANOG (Dec 14)
- Re: Log4j mitigation Owen DeLong via NANOG (Dec 15)