Skip to content

How to harden an NSQ container (and is nsqio/nsq:v1.3.0 safe for untrusted workloads?)

NSQ is a realtime distributed message queue that every producer and consumer in your system connects to, which is exactly why its container should be one of the tightest. A stock docker run nsqio/nsq:v1.3.0 is not: graded on IronClaw's seven-dimension containment scale it scores 48 of 100, grade D (porous). Higher is safer. A short list of runtime flags takes the same image to 89 of 100, grade B, one point off an A, and the one dimension it cannot reach is the one a broker needs by definition (publishers and subscribers must connect to it). Here are the exact gaps and fixes from the scan data.

Every number here comes from a read-only docker inspect of nsqio/nsq:v1.3.0, the same data behind its isolation scorecard. No workload is executed. How scoring works →

Where the default configuration leaks

ironctl scan grades seven independent containment boundaries. On a default docker run nsqio/nsq:v1.3.0, four fail or warn:

Dimension Verdict Score What the scan found
Non-root user (uid != 0) ❌ FAIL 0/15 runs as root (uid 0); a container escape starts with host-uid 0
Dropped capabilities ❌ FAIL 4/20 default capability set retained (CAP_NET_RAW, CAP_MKNOD, and more)
Seccomp profile ✅ PASS 15/15 seccomp profile active
Network isolation / egress ⚠️ WARN 4/15 network=bridge: outbound egress is possible
Read-only root filesystem ❌ FAIL 0/10 root filesystem is writable
No docker.sock exposure ✅ PASS 15/15 no control socket mounted
No shared host namespaces ✅ PASS 10/10 no host PID/IPC/network sharing

The sharpest edges are root, the retained capabilities, and the writable rootfs: a protocol or client CVE that lands code execution lands it as uid 0, with CAP_NET_RAW and friends, on the process every message in your stack passes through, and with a filesystem it can rewrite to persist.

Harden it: the exact --fix remediation

ironctl scan my-nsq --fix prints one remediation per failed dimension, then one hardened run. For nsqio/nsq:v1.3.0:

  • --user 65532:65532 (Non-root, +15): run nsqd as an unprivileged uid. Point the data directory (--data-path) at a volume that uid owns.
  • --cap-drop=ALL (Dropped capabilities, +16): drop every Linux capability; add back only what the workload provably needs. NSQ needs none of the defaults for a standard listen on its TCP and HTTP ports.
  • --read-only --tmpfs /tmp (Read-only rootfs, +10): make the root filesystem read-only and mount the queue data path as an explicit writable volume. Removes the persistence surface.
  • Scoped network (Network isolation): --network=none scores the full 15 but is wrong for a broker, publishers and subscribers must reach it. Any named or bridge network scores 4 of 15 (a WARN, not a fail): a connection path exists. This is the one dimension a broker cannot max out. Contain it anyway: attach a user-defined network scoped to just its clients, with no default route out, so a compromised broker cannot call arbitrary internet addresses.

Before and after

# Before: 48/100, grade D
docker run -d --name nsq nsqio/nsq:v1.3.0 /nsqd

# After: 89/100, grade B (scoped private network for publishers and subscribers)
docker run -d --name nsq-hardened \
  --user 65532:65532 \
  --cap-drop=ALL \
  --security-opt=no-new-privileges \
  --read-only --tmpfs /tmp \
  -v nsq-data:/data \
  --network=nsq-internal \
  nsqio/nsq:v1.3.0 /nsqd --data-path=/data

Rescan: ironctl scan nsq-hardened reports 89/100 grade B. A 41-point swing with no custom image build, just the right flags. The only dimension still short of full marks is the network (4 of 15), because a broker exists to be connected through; network=none would score the last points but leave nothing able to publish or subscribe. That is the honest ceiling for a broker, and it is a clear step up from the default D.

Verify it on your own broker

# install (Homebrew)
brew install ironsecco/ironclaw/ironclaw

# grade your running container, then print the fixes
ironctl scan my-nsq
ironctl scan my-nsq --fix

ironctl scan also reads a docker-compose.yml service or a Kubernetes manifest, so you can grade the NSQ in your stack, not just a bare docker run.

Keep going