Just rolled out this mitigation to our servers, seems to be effective for CAS 6.3.x builds.
Our environment for reference: - Standalone Tomcat - OpenJDK - CAS and CAS-Management as deployed jars - CAS and CAS-Mangement built from cas-overlay and cas-management-overlay repos. Mitigated by adding “-Dlog4j2.FormatMsgNoLookups=true” into the Tomcat startup in systemd tomcat.service file. From: 'Richard Frovarp' via CAS Community <cas-user@apereo.org> Sent: Friday, December 10, 2021 3:29 PM To: cas-user@apereo.org Subject: [EXTERNAL SENDER] Re: [cas-user] log4j vulnerability Maybe? The one that I've seen https://logging.apache.org/log4j/2.x/security.html says set it as a system property, so -Dlog4j2.formatMsgNoLookups=true to your JVM and not in the config file. On 12/10/21 12:55 PM, Mike Osterman wrote: Yeah, it seems like setting the log4j2.formatMsgNoLookups to "true" in the log4j2.xml config file might do to trick. I'm guessing we'd do that somewhere here at the top? <?xml version="1.0" encoding="UTF-8" ?> <!-- Specify the refresh internal in seconds. --> <Configuration monitorInterval="5" packages="org.apereo.cas.logging"> <Properties> <Property name="baseDir">/etc/cas/logs</Property> </Properties> <Appenders> On Fri, Dec 10, 2021 at 10:41 AM 'Richard Frovarp' via CAS Community <cas-user@apereo.org<mailto:cas-user@apereo.org>> wrote: Using a new enough version of the JDK might also alleviate it? The other option is to throw the config option at the JDK to stop it from happening. That would seem to be easiest. On 12/10/21 12:36 PM, King, Robert wrote: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-44228 Has anyone attempted to mitigate this CVE yet? There seems to be two possible approaches to mitigation: 1 The sledgehammer approach of removing the JndiLookup.class from the jar files: zip –q –d log4j-core-*.jar org/apache/logging/log4j/core/lookup/JndiLookup.class 2. 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