aws-samples/kubernetes-log4j-cve-2021-44228-node-agentKubernetes DaemonSet that hot-patches JVMs to mitigate Log4j2 vulnerabilities (CVE-2021-44228, CVE-2021-45046) by disabling JNDI lookups, providing temporary protection until dependencies are updated.
This project is being deprecated as outlined below.
The project will cease to accept issues and will not be updated as of 2023-01-01. After this date, this project will be unsupported and no new releases or artifacts associated with this project will be generated.
The project repository will permanenetly archived (made read-only) as of 2023-04-01.
As noted in the original project documentation, this was always meant to be a temporary measure to aid Kubernetes users, and it only ever provided a partial mitigation of the security exposure from Log4j2 CVE-2021-44228 and CVE-2021-45046. It is strongly recommended that all users of Log4j update to a patched version of the project to fully mitigate any risk associated with these CVEs.
The release artifacts associated with the latest release will remain permanently available for consumers of this project that continue to deploy it in to their Kubernetes environments. Specifically, the DaemonSet manifest and ECR Public conainer image will remain available after deprecation, but will no longer be supported or updated.
AWS has developed an RPM that performs a JVM-level hot-patch which disables JNDI lookups from the Log4j2 library, mitigating Log4j2 CVE-2021-44228 and CVE-2021-45046.
The Apache Log4j2 CVE-2021-44228 node agent is an open source project built by the Kubernetes team at AWS. It is designed to run as a DaemonSet and mitigate the impact of Log4j2 CVE-2021-44228, which affects applications running Apache Log4j2 versions < 2.15.0 when processing inputs from untrusted sources. Running this DeamonSet will patch JVMs running in containers as well as on the host.
What it does: A cron entry will be installed on every worker node that runs a process looking for running JVMs and injects an agent which mitigates the Log4J2 CVE. All JVMs, including those running in containers will be hot-patched in this way. Currently, the hot-patch process is configured to run every 30min with a 15min jitter. The effective window can range from 15 to 45min between runs.
Note: You can find additional information about the Log4j2 vulnerability and AWS response in the AWS Security Bulletin.
Note: On 4/20/22, the image (v0.0.16) was updated with the latest patch for Amazon Linux 1 and 2. If you installed a previous version of this DaemonSet and it is still running, you should re-apply the daemonset.yaml file to install the latest RPM. If you no longer need the log4j patch, you should delete the DaemonSet and uninstall the RPM as older versions of the RPM (< 1.1-16) had a vulnerability that could allow an attacker to escape from a container and gain access to the underlying host.
Note: version 1.3-5 addresses ALAS2-2022-1806 and ALAS-2022-1601. See Amazon Linux "log4j hotpatch" <1.3-5 local privilege escalation to root for additional information.
kubectl apply -f https://raw.githubusercontent.com/aws-samples/kubernetes-log4j-cve-2021-44228-node-agent/main/daemonset.yaml
Spot check a single pod:
kubectl get pods -l job=node-patch-installer -n node-configuration-daemonset
kubectl logs <pod-name> -c node-patch-installer -n node-configuration-daemonset
or get confirmation for every node:
kubectl logs -l job=node-patch-installer -c node-patch-installer -n node-configuration-daemonset | grep 'installed'
If the installation was successful, the last line in the log file will read installed and verified otherwise an error will be logged.
daemonset.yaml file to reflect the new URI:tag of the image, then apply the manifest to your cluster.Apache Log4j2 < 2.15.0 JNDI features used in configuration, log messages, and parameters do not protect against attacker controlled LDAP and other JNDI related endpoints. An attacker who can control log messages or log message parameters can execute arbitrary code loaded from LDAP servers when message lookup substitution is enabled. From Log4j2 versions < 2.15.0, this behavior has been disabled by default. Full details can be found in the CVE bulletin.
You can find additional information about the Log4j2 vulnerability in the AWS Security Bulletin.
AWS has developed an RPM that performs a JVM-level hotpatch disabling JNDI lookups from the Log4j2 library, mitigating the Log4j2 issue for that applies to JVMs on the host as well as JVMs running in containers. This project packages up the RPM as a Kubernetes DaemonSet.
When installed, a process will run on every worker node that looks for running JVMs and injects an agent into the JVM to mitigate the Log4j2 vulnerability. The agent attempts to patch the lookup() method of all loaded org.apache.logging.log4j.core.lookup.JndiLookup instances to unconditionally return the string Patched JndiLookup::lookup(). This is designed to address the CVE-2021-44228 remote code execution vulnerability in Log4j2 without restarting the Java process.
This process by default is configured to run every 30 mins, and will add a layer of protection in clusters where applications have yet to be patched with an updated Log4j2 dependency.
You can find more details on the hotpatch in the AWS open source blog.
The container image is hosted in the aws-containers ECR Public repository.