🔄 Topic

Upgrading Hermes taught me that a clean test run and a new source checkout are not enough evidence for a security-sensitive service. The important question is more concrete: what code is the live process actually running, and can I recover safely if the upgrade is wrong?

🎯 Goal

Move Hermes to a newer release while preserving its local messaging protections, keeping the active runtime identifiable, and retaining a tested recovery path.

🛠 What I Did

I treated the upgrade as a deployment-verification exercise rather than a package update.

  • prepared the release independently of the production runtime, so installed extras and the existing service environment were not casually overwritten;
  • preserved the local protections that mattered at the messaging boundary, including suppression of provider-error details on WhatsApp;
  • checked focused regression suites and a synthetic database-upgrade fixture instead of using private conversations as test data;
  • confirmed the service PID, reported version, commit identity, imported source location, dependency health, database integrity, and connected messaging writers after activation;
  • kept a rollback reference plus owner-only snapshots of the prior runtime and configuration;
  • recorded an important limit: testing an old binary against the newer schema did not make a destructive schema downgrade safe. Restoring an older snapshot would also need reconciliation of anything received after the upgrade.

🔗 Key Cybersecurity Connections

This is deployment integrity in a small, practical form. A repository can contain the right commit while launchd or a service manager still starts an older checkout, a stale virtual environment, or a path modified by unrelated work. That gap is dangerous because the source review and the runtime reality can disagree without producing an obvious error.

Rollback deserves the same precision. “We have a backup” is not a recovery plan if it overwrites newer state or if nobody can identify which runtime the service was actually using. A safe rollback needs an exact target, a known previous artifact, and an explicit decision about what happens to data written after the cutover.

🔍 Investigation Questions

  • Which commit and source path does the running PID report?
  • Does the service import from the intended environment, not merely from the shell where I ran the check?
  • What local protections were preserved across the upgrade?
  • Can the old application read the upgraded data without pretending that this is a schema downgrade?
  • What newer state would a rollback risk replacing?

🚨 Detection Opportunities

Useful deployment signals include:

  • service version or source path differs from the reviewed release;
  • a process starts from a mutable shared checkout instead of an identified artifact;
  • dependency checks fail only under the service runtime;
  • a migration reports success but integrity or compatibility checks are missing;

  • a rollback plan says “restore backup” without addressing post-cutover data.

    event=deployment_identity_mismatch expected=reviewed_release_commit action=stop_and_verify_runtime_source_before_claiming_success

🧭 MITRE ATT&CK Techniques

No direct ATT&CK mapping claimed. This is defensive deployment assurance and recovery planning, not an adversary-technique analysis.

🗺 Visual Investigation Diagram

Reviewed release and preserved local protections
    ↓
Focused tests + synthetic upgrade fixture
    ↓
Activate the intended runtime
    ↓
Verify PID → version → commit → import path → dependencies
    ↓
Check messaging connections and database integrity
    ↓
Keep a named rollback target and protect newer state

⚠ Challenges

The tempting shortcut was to treat a clean source tree as evidence that production had changed. It was not. The service had to identify its own code and runtime before the upgrade could be described as verified.

📚 What I Learned

I learned to separate three claims: the code was reviewed, the files were installed, and the live service is running those files. Only the third claim describes the outcome users depend on.

➡ Next Steps

  • Keep runtime identity checks in future upgrade handoffs.
  • Exercise migration compatibility with synthetic data before a live cutover.
  • Treat rollback as a state-reconciliation problem, not only a Git operation.

🧠 Reflection

The useful habit here is slightly less glamorous than “upgrade completed”: ask the process to prove what it is. That makes a hidden path mistake visible before it becomes a long debugging session.

🧩 Lessons Learned

What worked

Verifying the active PID, source identity, dependencies, connections, and data state as separate checks.

What could have failed silently

The service could have continued running an older checkout or a mismatched environment while the repository looked perfect.

Fix / takeaway

Treat a deployment as complete only when the running service proves its release identity and the rollback boundary is explicit.

📈 Skill Progression Context

This strengthens my cybersecurity foundation in change management, deployment verification, and recovery-aware operations—skills that matter whenever a security control moves from a test environment into a real service.

😄 TL;DR

An upgrade is not “done” because code was tested or copied. It is done when the running service can prove the commit and environment it is actually using, with a recovery plan that respects newer state.