Well if you look to the right you won't see it, but if you look to the left you will see it.
Meaning, that for a successful attack to work, the infected host needs to first download a payload from ldap. And ldap runs on port 389/636. You probably can't see the log4j vulnerability in the https, but you should be able to see your servers querying weird stuff on internet on port 389/636. Just don't allow your important hosts to fetch payload on internet on port 389/636. Et voila! Look to the left, not to the right. Jean -----Original Message----- From: NANOG <nanog-bounces+jean=ddostest...@nanog.org> On Behalf Of Nick Hilliard Sent: December 11, 2021 7:12 AM To: Andy Ringsmuth <a...@andyring.com> Cc: nanog@nanog.org Subject: Re: Log4j mitigation Andy Ringsmuth wrote on 11/12/2021 03:54: > The intricacies of Java are over my head, but I’ve been reading about this > Log4j issue that sounds pretty bad. > > What do we know about this? What, if anything, can a network operator do to > help mitigate this? Or even an end user? The payload can be contained in https, so there is no way of detecting / stopping this at the network level. Installations need to be upgraded / fixed. 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
