zeek-fips

packaged by Chainguard

Chainguard Container for zeek-fips

Minimal FIPS compliant image with Zeek, a network security monitoring framework that turns live or captured traffic into structured logs, with zeekctl and the zkg package manager.

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/zeek-fips:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

Compatibility Notes

Chainguard's zeek-fips image is comparable to the upstream Zeek image. Like upstream, it runs as root and defaults to a bash shell, so commands such as zeek, zeekctl, zkg, and zeek-cut can be passed directly to docker run. It differs in the following ways:

• Zeek is installed into standard system paths instead of /usr/local/zeek. Binaries are in /usr/bin, configuration in /etc/zeek, scripts in /usr/share/zeek (site policy in /usr/share/zeek/site), plugins in /usr/lib/zeek/plugins, logs in /var/log/zeek, and spool files in /var/spool/zeek.
• PYTHONPATH is set to /usr/lib/zeek/python, so the broker Python bindings import as they do upstream.
• The Spicy and BinPAC toolchains (such as spicyc, spicyz, spicy-driver, spicy-dump, hiltic, hilti-config, binpac, bifcl), the Zeek headers, and a C++ compiler are not included; they come with the zeek-fips-dev package. The Spicy runtime is included, so analyzers precompiled with spicyz load when passed to zeek or placed in /usr/lib/zeek/spicy. Upstream ships the toolchains without a C++ compiler, so it cannot compile analyzers or plugins either.
• net-tools is not included, so ifconfig, route, and arp are not available. Use ip from iproute2, which zeekctl also uses to find local addresses.
• The FIPS build disables MD5. See FIPS Support.

Live capture needs the NET_RAW capability. The zeek binary carries no file capabilities, so this image runs as root, which holds NET_RAW by default.

Getting Started

To analyze a packet capture, mount the directory that holds it and run zeek with the site policy. Zeek writes its logs to the working directory:

docker run --rm -v "$PWD:/data" -w /data cgr.dev/ORGANIZATION/zeek-fips:latest \
  zeek -C -r traffic.pcap local

List the DNS queries from the resulting dns.log with zeek-cut:

docker run --rm -v "$PWD:/data" -w /data cgr.dev/ORGANIZATION/zeek-fips:latest \
  bash -c 'zeek-cut id.orig_h query < dns.log'

To monitor live traffic, give the container access to the host network and capture on an interface. Zeek writes logs until it receives SIGTERM, for example from docker stop:

docker run -d --name zeek --net=host -v "$PWD/logs:/logs" -w /logs \
  cgr.dev/ORGANIZATION/zeek-fips:latest zeek -C -i eth0 local

Replace eth0 with the interface you want to monitor.

Configuration

Zeek reads its site policy from /usr/share/zeek/site/local.zeek. To add your own scripts, mount a directory and pass the scripts on the command line after local:

cat > hello.zeek <<'EOF'
event zeek_init()
    {
    print "hello from zeek";
    }
EOF

docker run --rm -v "$PWD:/data" -w /data cgr.dev/ORGANIZATION/zeek-fips:latest \
  zeek -C -r traffic.pcap local hello.zeek

zeekctl uses /etc/zeek/node.cfg, /etc/zeek/networks.cfg, and /etc/zeek/zeekctl.cfg. Mount your own copies over them to run a standalone node or a single-host cluster with zeekctl deploy; the image has no ssh or rsync for remote nodes. zkg installs packages into /usr/share/zeek/site and keeps its state in /var/lib/zeek/zkg. Packages with a build step, such as C++ plugins and Spicy analyzers, need the zeek-fips-dev package and its compiler; build them in a separate stage and copy the results into /usr/lib/zeek/plugins or /usr/lib/zeek/spicy.

FIPS Support

The zeek-fips image uses the Chainguard FIPS provider for OpenSSL, with openssl-config-fipshardened. It differs from the non-FIPS image in these ways:

• MD5 is not available. Scripts that call md5_hash(), md5_hash_init(), md5_hmac(), anonymize_addr() with RANDOM_MD5, or the MD5 file analyzer stop with the fatal error MD5 is not available in FIPS builds of Zeek, which for traffic-driven scripts happens on the first matching packet. This includes the bundled policy/protocols/krb/md5-ticket-logging.zeek; load policy/protocols/krb/ticket-logging.zeek for SHA-256 ticket hashes instead. The ssh_server_host_key (SSH2) and mime_content_hash events are not raised. Logs keep their md5 columns, which stay empty; file and certificate hashes use SHA-1 and SHA-256, and SSH host keys only the SHA-256 fingerprint.
• ZeroMQ is built without CURVE encryption, so multi-node ZeroMQ clusters need cluster_backend_zeromq.use_curve_encryption = 0 or the Broker cluster backend.
• Kerberos ticket decryption with KRB::keytab works only for the RFC 8009 aes-sha2 encryption types.

By default, OpenSSL also loads a legacy provider that serves non-approved algorithms such as MD5. To restrict OpenSSL to approved algorithms only, set CHAINGUARD_LEGACY_ALLOWED=0, and with zeekctl add env_vars=CHAINGUARD_LEGACY_ALLOWED=0 to zeekctl.cfg.

Documentation and Resources

• Zeek documentation
• Zeek quickstart
• Zeek package manager

What are Chainguard Containers?

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All other Chainguard Containers are built with Chainguard OS, Chainguard's minimal Linux operating system designed to produce container images that meet the requirements of a more secure software supply chain.

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• Minimal design, without unnecessary software bloat
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• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

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In all other cases, including Chainguard Containers tagged as :latest or with a specific version number, the container images include only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager.

Although the -dev container image variants have similar security features as their more minimal versions, they include additional software that is typically not necessary in production environments. We recommend using multi-stage builds to copy artifacts from the -dev variant into a more minimal production image.

Need additional packages?

To improve security, Chainguard Containers include only essential dependencies. Need more packages? Chainguard customers can use Custom Assembly to add packages, either through the Console, chainctl, or API.

To use Custom Assembly in the Chainguard Console: navigate to the image you'd like to customize in your Organization's list of images, and click on the Customize image button at the top of the page.

Learn More

Refer to our Chainguard Containers documentation on Chainguard Academy. Chainguard also offers VMs and Libraries — contact us for access.

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