Analyzing the Canonical DDoS Impact on Docker Build Pipelines and Railway Uptime

Canonical under DDoS: what my Railway logs and uptime say about my real exposure

Canonical’s distribution infrastructure faced a volumetric DDoS attack in 2025 targeting APT repositories and mirrors. Analysis of personal Railway logs revealed 11 silent ‘Unable to fetch’ failures across 4 deployments despite no application code changes. This event highlights the danger of invisible dependencies on public mirrors during critical production builds.

Why This Matters

Developers often treat shared public infrastructure like Canonical mirrors as a utility that ‘just works,’ but a DDoS reveals these as critical single points of failure in the supply chain. While application code may be perfect, a 23.4-second average for ‘apt-get update’ can spike to a 10-minute timeout during an attack, effectively bricking urgent production deployments. This asymmetry exists because indie developers lack the private Nexus or Artifactory mirrors used by large teams, leaving them directly exposed to public mirror outages.

Key Insights

• Railway logs showed 11 silent ‘Unable to fetch’ errors in 30 days during the Canonical DDoS incident (2025).
• Standard ‘apt-get update’ build steps averaged 23.4 seconds on normal days according to build-steps-june.txt data.
• Simulated mirror downtime showed an 18-second failure loop for ‘apt-get update’ in Ubuntu 22.04 containers before timing out.
• Indie stacks often share the same ‘archive.ubuntu.com’ infrastructure as millions of others, creating a massive centralized failure surface.
• Using ‘slim’ images based on Debian (e.g., node:20-slim) shifts the dependency to Debian mirrors but retains the same architectural risk.
• Docker layer caching on platforms like Railway is invalidated by any change prior to the apt step, forcing a fresh hit on public mirrors during active development.

Working Examples

Searching exported Railway logs for anomalous latency or APT timeouts.

grep -E "(apt-get|apt |dpkg)" railway-build-logs-june.txt | grep -E "(timeout|could not|failed|Unable to fetch)" | sort | uniq -c | sort -rn

Calculating average time for apt-get update steps from build logs.

awk '/apt-get update/{start=$1} /done/{if(start) print $1-start; start=""}' railway-build-steps-june.txt | awk '{sum+=$1; n++} END {print "Average:", sum/n, "seconds"}'

Simulating downed mirrors by redirecting DNS to localhost within a container.

docker run --add-host=archive.ubuntu.com:127.0.0.1 --add-host=security.ubuntu.com:127.0.0.1 ubuntu:22.04 bash -c "time apt-get update 2>&1 | tail -5"

Resilient Dockerfile pattern to prevent build failure during mirror degradation.

RUN apt-get update --fix-missing || true && apt-get install -y --no-install-recommends curl 2>/dev/null || echo "WARNING: apt degraded, continuing without optional packages"

Practical Applications

• Use Case: Implementing ‘—fix-missing’ and ’|| true’ in Dockerfiles ensures builds continue during mirror degradation for non-critical packages.
• Pitfall: Relying on Docker layer caching without realizing that any upstream file change invalidates the cache and forces a fresh hit on public mirrors.
• Use Case: Auditing base images with ‘docker image inspect’ to map hidden dependencies on Ubuntu or Debian infrastructure across the stack.
• Pitfall: Using ‘apt-get update’ without ‘—no-install-recommends’ increases the number of external requests and the overall attack surface.

References:

• https://dev.to/jtorchia/canonical-under-ddos-what-my-railway-logs-and-uptime-say-about-my-real-exposure-jm3