securitylinuxops

Hardening Scrapers on Minimal Distros: SELinux, AppArmor and Container Best Practices

UUnknown

2026-02-14

11 min read

A practical 2026 guide to hardening scrapers on minimal distros: SELinux/AppArmor, container flags, egress policies, secrets and supply-chain checks.

Harden scrapers on minimal distros — practical, production-ready patterns for 2026

Hook: You run scrapers on lightweight Linux builds to save cost and boot fast — but minimal distros make it easy to miss critical hardening: app confinement, egress controls, secret leakage, and invisible supply-chain risks. This guide gives compact, reproducible patterns (SELinux/AppArmor, container flags, nftables, secrets, SBOMs and CI checks) you can apply to Raspberry Pi fleets, cloud VMs and scratch-based containers in 2026.

Executive summary — the one-minute checklist

Use a MAC where available: Prefer SELinux (Fedora/RHEL) or AppArmor (Ubuntu) if you can; otherwise use user namespaces + seccomp + bubblewrap.
Containerize with hardening flags: readonly rootfs, no-new-privs, drop CAP_*, seccomp and resource limits.
Lock outbound traffic: egress-only rules to proxy endpoints using nftables or eBPF-based controls.
Manage secrets securely: Vault/KMS, kernel keyring for ephemeral secrets, avoid env vars in logs.
Mitigate supply-chain risk: generate SBOMs, require signed images (cosign/Sigstore), pin base images and vendor dependencies.
Scale anti-bot safely: centralized rate-limiters, rotating proxy pools, and circuit breakers to avoid mass bans.

The 2026 context — what’s changed and why it matters

By early 2026, a few trends affect scraper security:

Broader adoption of Sigstore/Cosign for container signing and attestation — verifying provenance is now standard in many CI pipelines.
eBPF tooling maturity: lightweight eBPF-based network policy and observability tools are available for edge and minimal systems (useful where full CNI stacks are heavy).
Supply-chain attacks and malicious packages continued through 2024–2025, driving SBOM enforcement, reproducible builds and artifact signing.
Edge compute hardware (Raspberry Pi 5 and similar) runs scraping workloads; constrained devices need security without heavyweight daemon stacks.

Choose the right minimal distro and MAC strategy

Not all minimal distros are equal when it comes to Mandatory Access Control (MAC):

SELinux: Available and battle-tested on Fedora, RHEL, Rocky — best for fine-grained, label-based confinement. Slightly heavy for tiny images but usable via SELinux-enabled containers.
AppArmor: Default on Ubuntu; easier to author quick profiles for scrapers. Good tradeoff for many minimal deployments.
No MAC: Alpine, Tiny Core and some minimal builds omit MAC by default. If you use them, substitute with user namespaces + seccomp + bubblewrap (bwrap) or run rootless Podman.

Decision matrix (short)

If you manage VMs/OS images across fleet and want strong policies: use a SELinux-enabled minimal base (Fedora Minimal or Rocky trimmed) and ship targeted policies.
If you prefer Ubuntu family: use AppArmor profiles and systemd sandboxing to constrain scraping processes.
If you must use Alpine or tiny images: rely on container-level hardening (seccomp, userns, drop caps) and host egress controls.

App confinement patterns (SELinux and AppArmor examples)

Start with containment at the OS level where supported, then add container-level controls. Below are practical snippets.

AppArmor: quick profile for a scraper

Place this in /etc/apparmor.d/usr.bin.scraper and load with apparmor_parser. It allows network via proxy and a log directory only.

# /etc/apparmor.d/usr.bin.scraper
  /usr/bin/scraper {
    # basic
    import 

    # read-only code
    /usr/bin/scraper r,
    /usr/lib/** r,

    # allow access to logs
    /var/log/scraper/ rw,

    # allow network through datagram/stream
    network inet stream,
    network inet dgram,

    # deny everything else
    deny /** w,
  }

SELinux: a small module to allow scraper logs and network

Use a custom SELinux module if you run on Fedora/RHEL. This is a minimal example; adapt types to your packaging.

# scraper.te
  module scraper 1.0;

  require {
    type unconfined_t;
    class file { read write append open };
    class tcp_socket name_connect;
  }

  # allow unconfined_t to write logs (for demo only — prefer a proper type)
  allow unconfined_t self:file { read write append open };
  # allow network connect
  allow unconfined_t self:tcp_socket name_connect;

Build with checkmodule/semodule_package and install with semodule -i scraper.pp. Note: SELinux policy work benefits from targeted policy types rather than unconfined_t allowances — turn this into a proper type for production.

Container hardening for minimal hosts

Whether you run Docker, Podman or containerd, apply these baseline flags. Prefer rootless runtimes on minimal distros when kernel/userns supports them.

Recommended runtime flags

# Example docker/podman run
  docker run --rm \
    --read-only \
    --tmpfs /tmp:exec,mode=1777 \
    --cap-drop ALL \
    --cap-add NET_BIND_SERVICE \
    --security-opt no-new-privileges:true \
    --security-opt seccomp=/etc/seccomp/scraper.json \
    --network none \
    --label app=scraper \
    --memory=512m --pids-limit=64 \
    myorg/scraper:2026.01.01

Key points: readonly rootfs, minimal capabilities, seccomp profile and resource caps. Do not expose container network directly — route through a host proxy or a dedicated proxy container.

Use distroless or scratch images with a small runtime

Minimize binaries in your image. Example Dockerfile for a Go scraper (multi-stage, static):

FROM golang:1.21 AS builder
  WORKDIR /src
  COPY . .
  RUN CGO_ENABLED=0 GOOS=linux go build -ldflags='-s -w' -o scraper ./cmd/scraper

  FROM scratch
  COPY --from=builder /src/scraper /scraper
  USER 1000:1000
  ENTRYPOINT ["/scraper"]

Egress restrictions and network policies — keep scrapers talking only to proxies

A common mistake: scrapers can reach the public internet directly if a machine or container misconfiguration happens. Lock egress to only your proxy pool and essential services (time, DNS, package mirrors).

nftables example — allow only proxy IPs outbound

# /etc/nftables.conf snippet
  table ip filter {
    chain output {
      type filter hook output priority 0;
      policy drop;

      # allow loopback and local subnet (adjust as needed)
      iif lo accept
      ip daddr 10.0.0.0/8 accept

      # allow DNS to your local resolver
      udp dport 53 ip daddr 127.0.0.1 accept

      # allow outbound to proxy pool (replace IPs)
      ip daddr { 203.0.113.10, 203.0.113.11 } tcp dport 3128 accept

      # allow NTP/time sync
      udp dport 123 accept

      # log and drop everything else
      counter drop
    }
  }

This keeps accidental direct access from containers or processes from exposing your IP pool to target sites.

Lightweight eBPF options

If you run many scrapers on edge hardware, consider tiny eBPF programs for per-process egress filtering or observability. Tools matured by 2026 let you attach filters without a heavyweight CNI — great for Raspberry Pi fleets.

Secrets management for scrapers — ephemeral, audited, and minimal-footprint

Proxy credentials, API keys and SSH keys need different treatment on minimal systems. The goal: never persist secrets in plain text or container layers, and remove them from process environments after bootstrap.

Options ranked by footprint

OS KMS + Vault Agent — best for fleet with central management (Vault with transit and agent injection).
Kernel keyring — low footprint; good for ephemeral secrets on hosts. Example with keyctl shown below. See storage and on-device guidance: storage on-device.
SOPS or sealed secrets — encrypt secrets at rest in repo or config; decrypt at deploy time with KMS.
Docker/Podman secrets — OK for single-host setups but be careful with backups and logs.

Example: kernel keyring for ephemeral proxy creds

# add secret (on host at deploy)
  keyctl padd user proxy-creds "user:pass" @u

  # in scraping process (read, then remove)
  SECRET=$(keyctl print $(keyctl search @u user proxy-creds))
  # use SECRET, then remove
  keyctl unlink $(keyctl search @u user proxy-creds) @u

Pros: no file on disk, small footprint. Cons: keyring lifecycle management can be tricky; kernel versions vary on minimal distros.

Vault Agent with minimal footprint

Vault has a lightweight agent binary (single static Go). Configure agent to write secrets to an in-memory tmpfs or stdin of the scraper process. Use short TTLs and renewals to limit blast radius.

Supply-chain resilience — signing, SBOMs and pinning

Producers of scraping code often pull many small libraries or system packages. By 2026, you should require provenance for any image or artifact deployed.

Mandatory steps

Generate an SBOM (syft) for every build and store it alongside artifacts.
Sign images and artifacts with cosign/Sigstore and validate signatures in deployment pipelines — integrate checks into CI (see CI/CD hardening patterns).
Scan images with Trivy or similar during CI and block known CVEs.
Pin base images to digests, not tags (example: myorg/scraper@sha256:...).

# CI snippet (bash)
  syft myorg/scraper:latest -o json > sbom.json
  trivy image --severity HIGH,CRITICAL myorg/scraper:latest
  cosign sign --key k8s://example-key myorg/scraper:latest
  cosign verify myorg/scraper:latest

By 2026 many orgs require signed image provenance. If you don't verify, you accept risk from compromised registries or CI supply chains.

Anti-bot, rate-limiting and proxy architecture (security-first)

Hardening isn't just about containment — it's about behaving in ways that limit operational risk:

Centralized rate-limiter: a token-bucket service (Redis or local) that workers consult before issuing requests to a target domain. Enforce per-target and per-proxy limits.
Proxy pool isolation: run proxies in a separate security boundary and enforce host nftables to only allow scraper hosts to talk to that pool.
Circuit breaker: if many 429/403 responses occur, bail out and rotate strategy to prevent wholesale IP bans.

Example token-bucket (pseudo-Redis)

# pseudo-code
  # Lua script used by Redis for atomic token acquire
  local key = KEYS[1]
  local now = tonumber(ARGV[1])
  local rate = tonumber(ARGV[2]) -- tokens per second
  local capacity = tonumber(ARGV[3])
  local token = tonumber(redis.call('get', key) or capacity)
  local last = tonumber(redis.call('get', key..":t") or now)
  token = math.min(capacity, token + (now-last)*rate)
  if token < 1 then return 0 end
  token = token - 1
  redis.call('set', key, token)
  redis.call('set', key..":t", now)
  return 1

Workers must check the bucket before issuing a request. Integrate backoff and jitter to reduce bursts.

Observability and runtime checks

Visibility reduces mean time to detect misconfiguration and supply-chain compromise. For minimal systems use lightweight metrics and eBPF-based traces if possible.

Export metrics: request counts, proxy auth failures, DNS anomalies, process restarts.
Use eBPF observers for syscall patterns and unexpected outbound sockets (low overhead).
Alert on sudden traffic spikes, high 403/429 ratios, or image signature mismatches.

Operational checklist — deploy this in your next sprint

Pick minimal distro with a MAC if possible (Ubuntu minimal for AppArmor, Fedora minimal for SELinux).
Containerize with readonly rootfs, seccomp, no-new-privs, drop caps; prefer rootless where supported.
Deploy nftables rules that only allow outbound to your proxy pool and essential services.
Use Vault or kernel keyring to inject ephemeral secrets at runtime; avoid environment variables with plaintext secrets.
Generate SBOMs, scan images, sign artifacts and block unsigned images in CI/CD.
Implement token-bucket rate-limiter and circuit breaker shared by all scrapers.
Monitor with lightweight metrics and eBPF-based connection traces; alert on anomalies.

Concrete examples and troubleshooting tips

Why does my minimal container still reach the internet?

Common causes:

Host nftables/iptables allow broad egress for the container's network namespace — check output chain and container network mode.
Proxy misconfiguration — proxy auth may fallback to direct connect; enforce proxy-only access with environment and kernel rules.
Missing seccomp or CAP_NET_RAW allowed, enabling bypass — drop unnecessary caps.

Debugging app confinement failures

AppArmor: tail /var/log/syslog and /var/log/kern.log for "apparmor=\"DENIED\"" entries; use aa-logprof to generate profile tweaks.
SELinux: use ausearch -m avc -ts recent and sealert or setenforce 0 temporarily (only for debugging!)

Future-proofing and predicted trends for scrapers in 2026+

Expect the following through 2026 and beyond:

Policy attestation will be required in regulated teams: CI pipelines will block unsigned artifacts by default.
eBPF will displace some heavyweight CNIs for egress filtering at the host level on edge fleets.
Provenance metadata (in-toto + Sigstore) will be standard for third-party libraries used in scrapers.

Quick reference: minimal commands and templates

Systemd unit sandbox example

[Unit]
  Description=Scraper worker

  [Service]
  ExecStart=/usr/bin/podman run --rm --name scraper-worker myorg/scraper:2026.01.01
  PrivateTmp=yes
  NoNewPrivileges=yes
  ProtectSystem=full
  ProtectHome=yes
  RestrictAddressFamilies=AF_INET AF_INET6
  MemoryMax=512M

  [Install]
  WantedBy=multi-user.target

Podman rootless tip

On minimal hosts, run podman in rootless mode to avoid host-level privilege escalation. Configure user namespaces and subuids/subgids in /etc/subuid and /etc/subgid.

Actionable takeaways

Start small: apply nftables egress rules and container readonly + no-new-privs today.
Then add provenance: require cosign verification in CI and produce SBOMs (syft) on every build.
Operationalize secrets: use Vault or kernel keyring for ephemeral secrets; rotate frequently.
Architect for rate-limiting: central token-buckets + proxy pools + circuit breakers to avoid mass bans.

Final notes on trade-offs

Minimal distros force you to choose: add OS-level MAC for the strongest guarantees, or keep a tiny base and push hardening into the container and host network layers. Either path works if you apply layered security: confinement, least privilege, network allowlists, secrets lifecycle, and supply-chain verification.

Call to action

Ready to harden your scraper fleet? Start with the one-minute checklist above, generate an SBOM from your latest image, and run a signed-deploy test in staging. If you want a ready-made repo with hardened Dockerfiles, systemd units, nftables templates and CI snippets (cosign + syft + trivy), clone our sample starter kit and run the pre-flight checks on one node this week — then roll to the fleet. Secure scraping is incremental: ship confinement and provenance in your next sprint.

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